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395 Cards in this Set
- Front
- Back
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What are the chief cells of the muscle tissue called?
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Muscle fibers
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Muscle fibers are long cells capable of contracting along their longitudinal axis (True/False)
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True
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What other type of tissue besides muscle tissue is found in muscles?
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Connective tissue
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What is the function of connective tissue in muscles?
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Harness contractions of muscle tissue to perform useful work.
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What are the three types of muscle tissue? What is their primary function?
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1. Skeletal muscle: move the body by pulling on bones of the skeleton
2. Cardiac muscle: pushes blood through the arteries and veins of the circulatory system 3. Smooth muscle: pushes fluid and solids along digestive tract and perform varied functions in other systems |
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What are the four basic properties of all muscle tissues?
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1. Excitability: the ability to respond to stimulus from nervous system or hormones
2. Contractility: ability to shorten actively and exert pull or tension that can be harnessed by connective tissue 3. Extensibility: ability to continue to contract over a range of resting lengths e.g. a smooth muscle cell can be stretched to several times its original length and still contract when stimulated. 4. Elasticity: ability to rebound towards its original length after a contraction |
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1. What kind of stimulus do skeletal muscles usually respond to?
2. What kind of stimulus do some smooth muscles respond to? |
1. Stimulation from nervous system
2. Circulating hormones |
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Which of the four basic tissue types can be found in the muscle?
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All, but consists primarily of muscles tissue.
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How many skeletal muscles can be found in the muscular system of the human body?
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more than 700
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All skeletal muscles that can be controlled voluntarily are part of the muscular system (True/False)
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True
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What are skeletal muscles?
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Contractile organs directly or indirectly attached to bones of the skeleton.
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What are the functions of the skeleton muscles?
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1. Produce skeletal movement
2. Maintain posture and body position 3. Support soft tissues 4. Regulate entering and exiting of material (orifices) 5. Maintain body temperature |
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Holding the head in a position when reading a book or balancing the weight of the body above the feet when walking involves the _________ of muscles that stabilize the joints.
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Contraction
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The abdominal wall and the floor of the pelvic cavity consist of layers of ________ muscle that support the weight of the visceral organs and protect internal tissues from injury
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Skeletal
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What is the function of skeletal muscles that encircle the openings (orifices) of the digestive and urinary tracts?
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Provide voluntary control over swallowing, defecation and urination.
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Muscle contractions require energy, and whenever energy is used in the body, some of it is converted to ______
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Heat
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Why is heat lost by contracting muscles important?
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Keep sour body temperature in the range required for normal functioning.
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What are the two Greek words anatomist often use to name structural features of muscles and their components and what do they mean?
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1. Sarkos ("flesh")
2. Mys ("muscle) |
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What are the three concentric layers, or wrappings, of connective tissue on the skeletal muscles?
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1. Epimysium (outer)
2. Perimysium (central) 3. Endomysium (inner) |
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What type of connective tissue makes up the epimysium?
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Dense irregular connective tissue
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What is the function of the epimysium?
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Separates muscle from surrounding tissue and organs and is connected to deep fascia
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What is the function of perimysium?
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Divides muscles into a series of internal compartments each containing a bundle of muscle fibers.
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The bundle of muscle fibers in the compartments made by the perimysium are called ______
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Fascicle
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What kind of connective tissue fibers make up the perimysium?
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1. Collagen fibers
2. Elastic fibers |
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What does the perimysium contain besides connective tissue and what are their functions?
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Blood vessels and nerves: branch to supply each individual fascicle.
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What is the function of the endomysium?
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1. Surrounds each skeletal muscle fiber
2. Bind each muscle fiber to its neighbor 2. Support capillaries that supply individual fibers. |
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What kind of connective tissue fibers make up the endomysium?
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Reticular fibers
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What kind of muscles in between the endomysium and muscle fiber function in the regeneration and repair of damaged muscle tissue?
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Myosatellite cells
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The connective tissue fibers of the endomysium and perimysium are interwoven, and those of the perimysium blend into the epimysium (True/False)
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True
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The collagen fibers of the epimysium, perimysium, and endomysium often converge to form a _______
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Tendon
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What is the function of a tendon?
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Attaches skeletal muscle to bone, skin, or another muscle
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What is an aponeuroses?
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Tendons that form thick, flattened sheets
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How is the tendon strongly bonded to the bone so muscle contraction can exert a pull on the attached bone?
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The tendon fibers are interwoven into the periosteum and matrix of the associated bone.
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Why are skeletal muscles often called voluntary muscles?
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Because their contractions can be voluntarily controlled.
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The connective tissues of the epimysium, perimysium, and endomysium contain the nerves and blood vessels that supply the muscle fibers (True/False)
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True
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What system controls skeletal muscles?
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The nervous system
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Chemical communication between a synaptic terminal of the neuron and a skeletal muscle fiber occurs at a site called the __________
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Neuromuscular synapse
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What are other names for the neuromuscular synapse?
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1. Myoneural junction
2. Neuromusclar junction |
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Each muscle fiber has several neuromuscular synapses located throughout the length of the muscle fiber (True/False)
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False. Each muscle fiver has one neuromuscular synapse, usually located midway along its length.
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What is the specialized area of the skeletal muscle fiber where the synaptic terminal of a neuron binds?
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Motor end plate
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Muscular contractions require tremendous quantities of energy (True/False)
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True
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The blood vessel supplying a skeletal muscle enter the __________ alongside the associated nerves, and the vessels and nerves follow the same branching pattern through the ____________. Once within the _________ the arteries supply an extensive capillary network around each muscle fiber.
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Epimysium, perimysium, endomysium
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What feature of the muscle fiber capillaries allow them to tolerate changes in the length of the muscle fiber?
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They are coiled rather than straight.
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Describe the difference between a tendon and aponeurosis.
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Tendons are collagenous bands that connect skeletal muscle to the skeleton. Aponeuroses are thick flattened tendinous sheets.
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What is the difference between a myoneural junction and a motor end plate?
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A myoneural junction (also called a neuromuscular synapse) is the site where the axon meets the muscle sarcolemma, or cell membrane. A motor end plate is the region of the sarcolemma at the neuromuscular synapse.
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Fibromyalgia is a ______ disorder characterized by abnormalities in central nervous system ______ processing
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Neurosensory, pain
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What are the symptoms associated with fibromyalgia?
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1. Chronic widespread pain with associated fatigue
2. Poor sleep 3. Stiffness 4. Cognitive difficulties 5. Multiple somatic symptoms 6. Anxiety 7. Depression |
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Patients diagnosed with fibromyalgia experience ____ that radiates from the ______ skeleton over widespread areas of the body, most frequently involving muscles and musculoskeletal junction, but often involving ________
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Pain, axial, joints
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Pain in fibromyalgia is often described as burning, exhausting or unbearable, and often originates from multiple _______ sites
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Tender
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What are the common tender sites in fibromyalgia?
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1. Knee (medial surface)
2. Humerus (area distal to the lateral epicondyle) 3. Skull (near external occipital crest of the skull) 4. The junction between the second rib and its costal cartilage |
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An additional clinical criterion for fibromyalgia is that the _____ and ______ can not be explained by other mechanisms
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pain, stiffness
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What is the most common musculoskeletal disorder affecting women under age 40?
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Fibromyalgia
Note: 3 to 6 million individuals in the United States may have this condition |
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What is the diagnostic to fibromyalgia since many of its symptoms can be attributed to other problems?
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Pattern of tender points
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What is another disorder that ha symptoms similar to Fibromyalgia except for pattern of tender points?
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Chronic Fatigue Syndrome (CFS)
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What are symptoms of Chronic Fatigue syndrome?
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1. A sudden onset, generally following a viral infection
2. Fever 3. Enlargement of cervical lymph nodes 4. Disabling fatigue 5. Muscle weakness and pain 6. Sleep disturbance |
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Roughly ______ as many women as men are diagnosed with CFS
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Twice
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Both Fibromyalgia and Chronic Fatigue Syndrome treatments are currently limited to _______
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Relieving symptoms (when possible)
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What are the cell membrane and cytoplasm of the muscle fiber called?
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Cell membrane: sarcolemma
Cytoplasm: sarcoplasm |
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How do skeletal muscle fibers differ from a "typical" cell?
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1. They are very large
2. They are multinucleate 3. They have deep indentation in the sarcolemma that form a network of narrow tubules in the sarcoplasm called transverse tubules |
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A fiver from a leg muscles could have a diameter of ______
and a length equal to that of the entire _____ |
100 micrometer, muscle
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What leads to the multinucleate characteristic of a muscle fiber?
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During development, groups of embryonic cells called myoblasts fuse together to create individual skeletal muscle fibers. Each nucleus in a skeletal muscle fiber reflects the contribution of a single myoblast.
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Where are the nuclei of a muscle fiber located?
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Just inside the sarcolemma
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What cells during development fuse to form a muscle fiber?
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Myoblasts
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What characteristic distinguishes skeletal muscle fibers from cardiac and smooth muscle fibers?
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Multiple nuclei
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Some myoblasts do not fuse with developing muscle fibers, but remain in adult skeletal muscle tissue as _________
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Mysosatellite cells
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Which cells differentiate and assist in the repair and regeneration of a skeletal muscle when it is injured?
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Myosatellite cells
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Electrical impulse conducted by the sarcolemma and __________ help stimulate and coordinate _________
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Transverse tubules, muscle contractions
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The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of __________
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Myofibrils
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What is the shape, diameter and length of a myofibril?
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Shape: cylindrical
Diameter: 1-2 micrometer Length: as long as the entire cell |
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Surrounding each myofibril is a sleeve made up of membranes of the ________________, a membrane complex similar to the ______________ of other cells.
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Sarcoplasmic reticulum (SR), smooth endoplasmic reticulum
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What is the role of the sarcoplasmic reticulum?
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Essential role in controlling the contraction of individual myofibrils.
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On each side of a transverse tubule, the tubules of the SR enlarge,fuse, and form expanded chambers called ________
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Terminal cisternae (see Fig 9.3 d)
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What is another name for transverse tubules?
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T tubules
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Two terminal cisternae plus a transverse tubule is known as a _______
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Triad (see Figure 9.3d)
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There is direct connection between the terminal cisternae and transverse tubules of of triad (True/False)
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False. Although the membrane of a triad are in close contact and tightly bound together there is no direct connection between them
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__________ and _________ are scattered among the myofibril and provide the ATP needed to power muscular contractions.
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Mitochondria, glycogen granules
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How is the quantity of mitochondria in a typical muscle fiber different from most other cells in the body?
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It has hundred of mitochondria, more than most other cells in the body.
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Myofibrils consist of bundle of _________
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Myofilaments
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Myofilaments are protein filaments consisting primarily of the proteins ______ and _________
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Actin and myosin
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The actin filaments are found in __________ and the myosin filaments are found in ____________
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Thin filaments, thick filaments
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How are actin and myosin organized in a myofibril?
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In repeating units called sarcomeres
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What are repeating units of actin and myosin in a myofibril called?
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Sarcomeres (see Fig 9.4)
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What gives the sarcomere a banded appearance?
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Arrangement of thick and thin filaments
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All of the myofibril are arranged ______ to the long axis of the cell, with their sarcomere lying side by side. As a result, the entire muscle fiber has a _______ appearance corresponding to the bands of the individual _________
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parallel, banded, sarcomeres
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Each myofibrils has how approximately many sarcomeres and how are they arranged?
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10,000 sarcomeres in a linear series
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What is responsible for skeletal muscle fiber contractions?
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Interaction between the thick and thin filaments of the sarcomere
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What is the smallest functional unit of a muscle fiber?
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Sarcomere
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What filaments lie in the center of a sarcomere?
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Thick filaments
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A sarcomere extends between _________
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Two Z lines (mark ends of sarcomere)
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The thick filaments are linked by proteins of the ________
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M line (see Fig 9.4)
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What filaments are at either end of the sarcomere?
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Thin filaments
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Thin filaments are attached to interconnecting proteins that make up the ________
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Z line
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Another name for a Z line is ________
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Z disc
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In the _________ thin filaments pass between thick filaments
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Zone of overlap
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Each thin filament sits in a triangle formed by ______ thick filaments, and each thick filament is surrounded by ______ thin filaments
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three, six
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The difference in the size and density of thick filaments and think filaments account for the ______ of the sarcomere
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Banded appearance
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The A band of the area of the sarcomere containing _________
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Thick filaments
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The A band includes the _____, the ______, and the ________
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M line, H band, zone of overlap
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The __________ extends between the A band and the Z line
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I band
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The following bands and zones contain what kind of filaments?
1. A band 2. H band 3. Zone of overlap 4. I band |
1. A band: thick filaments and thin filaments
2. H band: thick filaments only 3. Zone of overlap: thick and thin filaments 4. I band: thin filaments only |
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The terms A band and I band are derived from the terms ________ and _______, which refer to the appearance of these bands when viewed under polarized light
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Anisotropic, isotropic
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A bands are ______ and I bands are _______
(dark or light?) |
dark, light
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List important structures starting from the muscle and going down to microfilaments
(see Figure 9.5) |
1. Epimysium
2. Perimysium 3. Fascicles (contain bundles of muscle fibers) 4. Endomysium 5. Muscle fiber 6. Microfibrils 7. Myofilaments |
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Each thin filament is a _______ strand ______ in diameter and ____ in lenghth
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twisted, 5-6 nm, 1 micrometer
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The twisted strand of a thin filament is called ______ and is composed of 300-400 globular _________ molecules
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F actin, G actin (see Fig 9.6)
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A slender strand of the protein _____ holds the F actin strand together
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Nebulin
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The thick filament binds to the thin filament at the _________ of the ________ molecule much the same way that a substrate molecule binds to the active site of an enzyme
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Active site, G actin
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Besides G actin, a think filament also contains the associated proteins _______ and _______
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Tropomyosin, troponin
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What is the function of tropomyosin?
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Tropomyosin molecules form a long chain that covers the active sites, preventing actin-myosin interactions
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What molecules prevents actin-myosin interactions?
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Tropomyosin
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_________ holds the tropomyosin strand in place
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Troponin
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What has to happen to the troponin-tropomyosin complex before a contraction can begin?
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The troponin molecules must change position, moving the tropomyosin molecules and exposing the active sites
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At either end of the sarcomere the think filaments are attached to the ________
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Z line
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Although called a line because it looks like a dark line on the surface of the myofibril, in sectional view the ______ is more like an open meshwork created by proteins called ________. For this reason this line is often called the ______
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Z line, actinins, Z disc
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What line lies in the middle of the I band?
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The Z line
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What is the diameter and length of:
1. Thin filaments 2. Thick filaments |
1. Diameter: 5-6 nm, Length: 1 micrometer
2. Diameter: 10-12 nm, Length: 1.6 micrometer |
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Thick filaments are composed of a bundle of _________
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Myosin molecules
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Approximately how many myosin molecules are in a thick filament?
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500 myosin molecules
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Each myosin molecule within a thick filament consists of a _________ myosin strand with and attached, elongate _________ and a free globular ________
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double, tail, head
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What is the structure of myosin in a thick filament
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A double strand with a globular head and an elongate tail (see Fig 9.6)
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Adjacent thick filaments are interconnected midway along their lengths by proteins of the _______
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M line
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Thick filaments ________ the M line whereas ends of thin filaments ________ the Z line
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run through, attach to
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The myosin heads project ______ from the M line and ______ the surrounding thin filaments
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away, towards
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Myosin head are also known as _________ because they connect thick filaments and thin filaments during a contraction.
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Cross-bridges
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Each thick filament has a core of ________
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Titin
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On either side of the M line, a stand of titin extends the length of thick filament and continues past the myosin portion of the thick filament to an attachment at the _______
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Z line
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The portion of the titin strand exposed within the I band is __________ and will _________ after stretching
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highly elastic, recoil
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In the normal resting sarcomere, the titin stand are completely ________
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relaxed
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Titin becomes tense only when ____________
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some external force stretches the sarcomere
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When the tension is removed, _____________ helps return the sarcomere to its normal resting length.
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the recoil of the titin fibers
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Why does skeletal muscle appear striated when viewed with a microscope?
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Because it is composed of myofilaments actin and myosin, which are arranged in such a way as to produce a banded appearance in the muscle.
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What are myofibrils? Where are they found?
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A cylindrical collection of myofilaments within a cardiac or skeletal muscle tissue
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Myofilaments consist primarily of what proteins?
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Actin and myosin, along with accessory proteins of the thin filament (tropomyosin and troponin)
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What is the functional unit of skeletal muscle?
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Sarcomere
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What two proteins help regulate actin and myosin interaction?
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Tropomyosin and troponin
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A contracting muscle fiber exerts a pull, or ________ and _______ in length
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tension, shortens
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Muscle fiber contraction results from interactions between the ______________ and the _____________ of the sarcomere
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thick filaments, thin filaments
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What theory is used to explain the mechanism for muscle contraction?
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Sliding filament theory
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The trigger for a contraction is the presence of __________, and the contraction itself requires the presence of ___________
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calcium ions, ATP
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Direct observation of contracting muscle fibers indicated what happens to the following during a contraction?
1. H band 2. I band 3. zone of overlap 4. A band |
1. H band: gets smaller
2. I band: gets smaller 3. Zone of overlap: gets larger 4. A band: width remains constant throughout contraction |
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The sliding filament theory explains the physical changes that occur between thick and thin filaments during contraction (True/False)
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True
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Sliding occurs when
1. the ______ of the thick filaments bind to the _______ on the think filament 2. When cross-bridge binding occurs, the myosin head ______ the M line, pulling the ________ towards the center of the sarcomere 3. The cross bridge then ________ and returns to its original position ready to repeat the cycle of ________, ________, ____, and ______" |
1. myosin heads, active sites
2. pivots towards, think filaments 3. detaches, attach, pivot, detach, return |
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When the thick filaments pull on the thin filaments, the ________ lines move toward the _____ line, and the _______ shortens
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Z, M, sarcomere
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In a muscle fiber, the amount of tension generated during a contraction depends on the number of ______________ that occur in the sarcomeres of the myofibrils
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cross-bridge interactions
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The number of cross-bridge interactions is determined by the degree of _________ between the thick and thin filaments
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overlap
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Only myosin heads within the ____________ can bind to the active sites and produce tension. The tension produced by the muscle fiber can therefore be related directly to the structure of the individual __________
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Zone of overlap, sarcomere
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At ______ the muscle fiver develops maximum tension
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optimal length
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The normal range of the sarcomere lengths is from _____ to ______ percent of the optimal length
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75, 130
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During normal movements, our muscle fibers perform over a broad range of intermediate lengths, and the _______ produced therefore varies from moment to moment. During an activity such as walking, in which muscles contract and relax in a cyclic fashion, muscle fiver are stretched to a length very close to ______ before they are stimulated to contract
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tension, optimal
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The immediate trigger for contraction is the appearance of ___________ in the __________
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free calcium ions, sarcoplasm
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In a muscle fiber intracellular calcium ion concentration is usually ________
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very low
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In most cells, the intracellular calcium ion concentration is low because any calcium ions entering the ______ are immediately ______ their cell membranes and into the _________
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cytoplasm, pumped across, extracellular fluid
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How is calcium transport different in muscle fibers compared to most other cells?
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Skeletal muscle fibers do pump calcium ions out of the cell like most other cells, but they also transport them into the terminal cisternae of the sarcoplasmic reticulum.
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Calcium ion concentration in the sarcoplasm is very _____
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low
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The calcium ion concentration inside the terminal cisternae may be as much as ____________ times higher compared to the sarcoplasm.
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40,000
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__________ at the ___________ cause a contraction by trigerring the release of calcium ions from the _________
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Electrical events, sarcolemmal surface, terminal cisternae
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The electrical "message" or impulse is distributed by the _______ that extend deep into the __________ of the muscle fiber
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transverse tubules, sarcoplasm
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A transverse tubule begins at the ______ and travels inwards at _________ to the membrane surface
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sarcolemma, right angles
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Branches from the transverse tubule _______ each of the individual _______ at the boundary between the _____ band and ____ band
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encircle, sarcomeres, A, I
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When an electrical impulse travels along a nearby T tubule, the _______ become freely permeable to _________
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terminal cisternae, calcium ions
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The calcium ions released by the terminal cisternae diffuse into the ________ , where they bind to ________
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zone of overlap, troponin
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What happens to troponin when calcium ions bind to it? What is the significance of this?
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It changes shape. This alters the position of the tropomyosin strand and exposes the active sites on the actin molecules allow cross bridging to occur and contraction to begin.
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The duration of the contraction usually depends on the duration of the _________
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electrical stimulation
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The changes in calcium permeability at the terminal cisternae is ________
a. permanent b. temporary c. long lasting |
b. temporary
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For the contraction to continue, additional ________ must be conducted along the T tubule
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electrical impulses
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If the electrical stimulation ceases, the ________ will recapture the calcium ions, the _________ complex will cover the _______, and the contraction will ______
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sarcoplasmic reticulum, troponin-tropomyosin, active sites, end
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What "cocks" the myosin head and prepares it for binding to an active site on actin?
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Binding and breakdown of ATP
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Once a cross-bridge has formed the myosin head ______ and pulls the ______ towards the center of the sarcomere
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pivots, thin filament
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What needs to happen for the myosin head to detach and re-cock for another cycle?
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An ATP must bind to the myosin head
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Even with continued stimulation, muscle fibers will eventually stop contracting as they _________
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run out of ATP
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Each myosin head may cycle ______ time each second
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five
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A muscle fiber contraction consumes enormous amount of _______
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ATP
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Are the following active (consumes energy) or passive processes?
1. Muscle contraction 2. Muscle return to resting length |
1. Muscle contraction: active
2. Return to resting length: passive |
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What factors help return a shortened muscle to its normal resting length?
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1. Elastic forces (such as the recoil of elastic fibers in the epimysium, perimysium, and endomysium)
2. Pull of other muscles 3. Gravity |
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___________ released by the motor neuron at the ________ synapse alter the __________ of the sarcolemma.
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Chemical, neruomuscular, transmembrane potential
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The change in transmembrane potential sweeps across the surface of the ______ and in the ________
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sarcolemma, transverse tubules
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The change in the transmembrane potential of the T tubules triggers the release of _____ by the _______
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calcium ions, sarcoplasmic reticulum
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The release of calcium ions by the sarcoplasmic reticulum initiate _______
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contraction
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Each skeletal muscle fiber is controlled by a _______ whose cell body is located inside the ________
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motor neuron, central nervous system (CNS)
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The ______ of the muscle fiber associated motor neuron extends into the periphery to reach the __________ of that muscle fiber.
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axon, neruromuscular synapse
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The expanded tip of the axon at the neuromuscular synapse is called the ________
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synaptic terminal
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The cytoplasm of the synaptic terminal contains numerous __________ and small secretory vesicles, called ________, filled with the molecules of __________
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mitochondria, synaptic vesicles, acetylcholine (ACh)
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Acetylcholine is an example of a _____________
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Neurotransmitter
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What is a neurotransmitter?
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A chemical released by a neuron to communicate with another cell
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Neural communication with another cell takes the form of a change in the _____________ of the cell
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Transmembrane potential
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What is the narrow space that separates the synaptic terminal from the motor end plate of the skeletal muscle fiber called?
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Synaptic cleft
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What enzyme breaks down the molecules of ACh? Where are they enzymes located?
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Acetylcholinesteras (AChE) in the synaptic cleft
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What is another name for acetylcholinesterase?
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Cholinesterase
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When an electrical impulse arrives at the synaptic terminal, _______ is released into the synaptic cleft
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Aceteylcholine (ACh)
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Where does ACh bind on the muscle fiber?
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Receptor sites on the motor end plate
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When ACh binds to receptor sites on the motor end plate it initiates a change in the local ____________
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Transmembrane potential
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A change in the transmembrane potential results in the generation of an ______________
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Electrical impulse, or action potential
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The action potential sweeps over the surface of the ________ and into each _______
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Sarcolemma, T tubule
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What happens if ACh bound to the motor end plate is not removed by acetylcholinesterase?
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Action potentials continue to be generated, one after another.
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When skeletal muscles run out of ATP after death what happens to calcium in the muscle fibers?
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The sarcoplasmic reticulum becomes unable to remove calcium ions from the sarcoplasm.
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When a person becomes “stiff as a board” after death, what is this condition called?
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Rigor mortis
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What causes rigor mortis? List steps.
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1. When death occurs, muscles are deprived of nutrients and oxygen
2. Skeletal muscle fibers run out of ATP and sarcoplasmic reticulum can not remove calcium ions from sarcoplasm 3. This calcium ions trigger a sustained contraction of muscle fibers 4. Since no ATP is present to help cross-bridges detach from the active sites, the muscle locks in the contracted position |
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In rigor mortis, not all of the body’s skeletal muscles are involved (True/False)
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False. All skeletal muscles are involved.
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How long does rigor mortis last?
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15-25 hours
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Rigor mortis lasts until the _________ enzymes released by ________ break down the _______
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Lysosomal, autolysis, myofilaments
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What are the key steps in the initiation of a contraction?
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1. ACh is released by synaptic terminal at neuromuscular synapse and binds to receptors on sarcolemma
2. Tansmembrane potential of muscle fiber changes and generates action potential 3. Sarcoplasmic reticulum released calcium ions into sarcoplasm 4. Calcium ions bind to troponin to move tropomyosin and expose active sites on thin filaments 5. Myosin cross-bridges form as myosin heads attach to active sites of actin 6. Repeated cycles of cross-bridge binding, pivoting and detachment occur to produce filament sliding and the muscle fiber shortens |
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Repeated cycles of cross-bridge binding, pivoting and detachment in a muscle fiber are powered by the hydrolysis of ______
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ATP
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What are the steps in muscle relaxation after contraction?
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1. ACh is broken down by acetylcholinesterase (AChE) ceasing action potential generation
2. Sarcoplasmic reticulum reabsorbs calcium ion from sarcoplasm 3. The troponin-tropomyosin complex returns to its normal position covering active sites 4. Cross-bridge interaction ends 5. No further sliding of microfilametns takes place and contraction ends 6. Muscle fiber returns passively to resting length. |
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What are abbrviations for
1. Acetylcholine 2. Acetylcholinesterase |
1. Acetylcholine: ACh
2. Acetylcholinesterase: AChE |
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How do terminal cisternae and transverse tubules interact to cause skeletal muscle contraction?
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Terminal cisternae store calcium ions, which are required to initiate contractile activities within skeletal muscle cells. A transverse tubule conducts the stimulation into the interior of the cell causing the release of calcium ions from the terminal cisternae, and this results in a muscle contraction.
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What is a neurotransmitter? What does it do?
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It is a chemical compound released by one neuron to affect the transmembrane potential of another.
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What is a motor unit?
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All muscle fibers controlled by a single motor neuron
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Although some motor neurons control a ______ muscle fiber, most control ______
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Single, hundreds
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What determines how fine the control of a movement can be?
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The size of a motor unit
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Which muscles require more precise control?
a. muscles of the eye b. leg muscles c. both require equal precision |
a. muscles of the eye
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In the muscles of the eye, where precise control is extremely important, a motor neuron may control ___________ muscle fibers. We have much less precise control over power-generating muscles, such as our leg muscles, where to ______ muscle fibers may be controlled by a single motor neuron.
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Two to three, 2000
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When motor units are stimulate the skeletal muscle ______
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Contracts
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What two factors does the amount of tension produced by a muscle depend on?
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1. The frequency of stimulation
2. The number of motor units involved |
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A single, momentary contraction is called a ______ and is the response to a _______
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Muscle twitch, single stimulus
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As the rate of _________ increases, tension production in muscle will rise to a peak and plateau at maximal levels. Most muscle contractions involve this type of stimulation.
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Stimulation
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A muscle fiber can have intermediate levels of contraction (True/False)
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False. Each muscle fiber either contracts completely or does not contract at all.
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Each muscle fiber either contracts completely or does not contract at all. What is this characteristic called?
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All or none principle
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Only some of the fibers in a motor unit contract at one time (True/False)
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False, all of the fibers in a motor unit contract at the same time.
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The amount of force exerted by the muscle as a whole depends on how many _______ are activate.
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Motor units
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How does the nervous system provide precise control over the pull exerted by a muscle?
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By varying the number of motor units activate at any one time.
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When a decision is made to perform a movement, specific groups of ________ are stimulated
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Motor neurons
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All motor neurons stimulated to perform a movement respond simultaneously (True/False)
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False. They do not respond simultaneously and over time the number of activated motor units gradually increases.
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The muscle fibers of each motor unit are intermingled with those of other units (True/False)
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True (see Fig 9.12)
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What is the significance of intermingling of motor units?
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Because of this intermingling, the direction of pull exerted on the tendon does not change as more motor units are activated, but the total amount of force steadily increases as the motor units are activated over time.
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The smooth but steady increase in muscular tension produced by increasing the number of active motor units is called _________
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Recruitment, or multiple motor unit summation
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Peak tension occurs when all the ________ in the muscle are contracting at the maximal rate of ________
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Motor units, stimulation
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Why can powerful contractions due to all motor units of a muscle being activated not last long?
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Because the individual muscle fibers used up their available energy reserve.
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What happens to less the onset of fatigue during periods of sustained contraction?
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Motor units are activated on a rotating basis, so that some of them are resting and recovering while others are actively contracting.
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Even when a muscle is at rest, some motor units are always _____
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Active
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The resting tension in a muscle is called ______
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Muscle tone
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In a resting muscle, motor units are _______, so that there is constant tension in the attached tendon but individual muscle fibers can have some time to relax.
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active
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What is the function of resting muscle tone?
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Stabilizes the position of bones and joints e.g. to maintain balance and posture
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What are muscle spindles?
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Specialized muscle cells monitored by sensory nerves that control the muscle tone in the surrounding muscle tissue.
Note: Reflexed triggers by activity in these sensory nerves play an important role in the reflex control of position and posture. |
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Exercise increases the activity of ________ and may enhance ________
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Muscle spindles, muscle tone
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What happens to muscle fibers as result of repeated, exhaustive stimulation?
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Develop a
1. larger number of mitochondria 2. higher concentration of glycolytic enzymes 3. larger glycogen reserves 4. larger number of myofibrils 5. larger number of thick and thin filaments in myofibrils |
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What is the enlargement of a muscle due to repeated, exhaustive stimulation called?
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Hypertrophy
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The intracellular changes due hypertrophy increase the amount of ______ produced when these muscles contract.
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tension
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What are good examples of hypertrophied muscle development?
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A champion weight lifter or a body builder
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When a skeletal muscle is not stimulated on a regular basis, it loses ______ and ______. The muscles become flaccid and the muscle fibers become _____ and ______
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Muscle tone, mass, weaker, smaller
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What is atrophy?
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Reduction in muscle size, tone and power
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Individuals paralyzed by spinal injuries or other damage to the nervous system will gradually lose ______ and _____ in the areas affected.
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Muscle tone, size
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A temporary reduction in muscle use can lead to atrophy (True/False)
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True. E.g. after wearing a cast
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Muscle atrophy is initially _______, but dying muscle fibers are not ______, and in extreme atrophy the functional losses are ______
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Reversible, replaced, permanent
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Why is physical therapy crucial in people temporarily unable to move temporarily?
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To prevent muscle atrophy an permanent functional losses.
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What are the three types of muscle fibers?
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1. Fast
2. Slow 3. Intermediate |
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The types of fibers that compose a muscle will, in part, determine its ________
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Action
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The differences in muscle fibers (fast, slow, intermediate) reflect a difference in the way they ___________
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Obtain the ATP to support their contractions
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What is another name for fast muscle fibers?
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White fibers
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Compare the following properties of fast, slow and intermediate muscle fibers?
1. Cross sectional diameter 2. Tension 3. Contraction speed |
1. X-sectional diameter Slow: small; Intermediate: intermediate; Fast: large
2. Tension Slow: low; Intermediate: intermediate; Fast: high 3. Contraction speed Slow: slow; Intermediate: fast; Fast: fast |
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Compare the following properties of fast, slow and intermediate muscle fibers?
1. Fatigue resistance 2. Color 3. Myoglobin content |
1. Fatigue resistance Slow: high; Intermediate: intermediate; Fast: low
2. Color Slow: red; Intermediate: pink; Fast: white 3. Myoglobin content Slow: high; Intermediate: low; Fast: low |
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Compare the following properties of fast, slow and intermediate muscle fibers?
1. Capillary supply 2. Mitochondria |
1. Capillary supply Slow: dense; Intermediate: intermediate; Fast: scarce
2. Mitochondria Slow: many; Intermediate: intermediate; Fast: few |
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Compare the following properties of fast, slow and intermediate muscle fibers?
1. Glycolytic enzyme concentration in sarcoplasm 2. Substrates used for ATP generation during contraction |
1. Glycolytic enzyme concentration in sarcoplasm Slow: low; Intermediate: high; Fast: high
2. Substrates used for ATP generation during contraction Slow: lipids, carbohydrates, amino acids (aerobic); Intermediate: primarily carbohydrates (anaerobic); Fast: Carbohydrates (anaerobic) |
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Fast fibers contain densely packed ______, large ______ reserves and relatively few _____
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Myofibrils, glycogen, mitochondria
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Most of the skeletal muscles fibers in the body are ______ fibers because they can contract in ______ seconds or less following stimulation
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Fast, 0.01
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The tension produced by a muscle is directly proportional to sarcomeres, so fast fiber muscles densely packed with myofibrils produce ______ contractions
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Powerful
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Fast muscle fiber contraction use enormous amounts of _____, and their ____ are unable to meet the demand. As a result their contractions are supported by _______ glycolysis.
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ATP, mitochondria, anaerobic
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Anaerobic glycolysis does not require ________ and convert glucose to _______
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Oxygen, lactic acid
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Why do fast fibers fatigue rapidly?
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1. Their glycogen reserves are limited
2. Lactic acid builds up |
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The acidic pH due to lactic acid build-up leads interferes with _________
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The contraction mechanism
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Which fibers support contraction by aerobic or anaerobic means?
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1. Slow: aerobic
2. Intermediate: anaerobic 3. Fast: anaerobic |
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What is another name for slow fibers?
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Red fibers
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Slow fibers take ______ times as long as fast fibers to contract after stimulation
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Three
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What are slow fibers specialized for?
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To continue contracting for extended periods of time, long after a fast muscle would have become fatigued.
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Why can slow fiber continue contracting for long periods of time?
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Because their mitochondria are able to continue producing ATP throughout the contraction
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In aerobic metabolism mitochondria absorb ____ and generate _____
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Oxygen, ATP
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Where does the oxygen required for aerobic metabolism in slow muscle fibers comes from?
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1. Extensive network of capillaries
2. Oxygen reserve due to myoglobin in slow fibers |
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Skeletal muscles containing slow muscle fibers have a more extensive network of _____ than do muscle dominated by fast muscle fibers
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Capillaries
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Slow fibers are red because they contain the red pigment _____ which is a structural protein related to _____.
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Myoglobin, hemoglobin
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Myoglobin binds ______
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Oxygen
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Which fibers have more mitochondria?
a. Fast b. Intermediate c. Slow |
c. Slow
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Whereas fast muscle fibers rely on their ______ reserves during peak leavels of activity, the mitochondria in slow muscle fibers can break down ______, ____, or even _____
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Glycogen, carbohydrates, lipids, proteins
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The leg muscles of marathon runners are dominated by ________
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Slow muscle fibers
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Intermediate have properties _____ between those of fast fibers and slow fibers
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Intermediate
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Histologically, intermediate fibers are very similar to ______
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Fast fibers
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The percentage of fast, slow, and intermediate fibers varies from one skeletal muscle to another (True/False)
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True
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Muscles have a _____ of muscle fiber types, but all the fibers within _____ are of the same type.
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Mixture, one motor unit
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What muscles do not have mixture of muscle fiber types? Why?
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Muscles of eye and hand (no slow fibers) where swift but brief contractions are required.
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Many back and calf muscles are dominated by _____ fibers; the muscles _______ almost continuously to maintain an upright posture.
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Slow, contract
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The percentage of fast versus slow fibers in each muscles of an individual is determined by ______. These differences have an effect on _______.
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Genetics, endurance
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A person with more slow muscle fibers than fast muscle fibers in their leg muscles will have an advantage in a:
a. marathon b. sprint |
a. Marathon
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The characteristics of muscle fibers change with ______. So a fast fiber can convert to an intermediate fiber.
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Physical conditioning
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Repeated, intense workouts promote the enlargement of ____ muscle fibers and muscular ______
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Fast, hypertrophy
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Training for endurance events, such as cross-country or marathon running increases the proportion of____ fibers in active muscles.
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Intermediate
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Endurance training promotes hypertrophy (True/False)
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False
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What is cross-training?
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Combination of aerobic (e.g. swimming) and anaerobic (e.g. weight lifting or sprinting) activities
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Cross-training enlarges ____ and improves _____ and ____
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Muscles, strength, endurance
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Why do some motor units control only a few muscle fibers, whereas other control many fibers?
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It depends on the number of branches in the motor neurons. A lesser number of branches (collaterals) results in the activation in only a few motor neurons.
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What is recruitment?
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It is the smooth but steady increase in muscular tension produced by increasing the number of active motor units.
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What is delayed-onset muscle soreness (DOMS)?
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Muscle soreness the day after a period of intense physical activity.
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It is believed that DOMS results from _______ of skeletal muscles. Any activity that calls for _______ muscle contractions than normal may result in DOMS.
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overuse, stronger
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What is more important for the onset of DOMS?
a. intensity of muscle contractions b. duration of the exercise |
a. intensity of muscle contractions
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What are some characteristics of DOMS?
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1. Its distinct for soreness experienced right after exercise
2. Begin several hours after exercise ends and may continue for three to four days 3. Highest when activity involves eccentric contractions vs. concentric and isometric contractions 4. Levels of CPK and myoglobin are elevated in the blood |
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What causes elevated levels of CPK and myoglobin in blood noticed during DOMS?
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Damage to muscle sarcolemmae
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Levels of CPK and myoglobin predict degree of soreness experiences (True/False)
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False
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What are five theories to explain DOMS?
|
1. Structural damage to sarcolemma and sarcoplasmic reticulum
2. Accumulation of lactic acid in skeletal muscles 3. Increased temperature within skeletal muscles 4. Decreased blood flow resulting in decreased available oxygen to skeletal muscles 5. Remodeling of myofibril resulting in sensation of muscular pain |
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Variations in macroscopic and microscopic organization of skeletal muscles can dramatically affect the ________, ______, and _______ of movement produced when muscle contracts.
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power, range, speed
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The muscle fibers of each fascicle lie _______ to one another, but the organization of the fascicles in the skeletal muscles can _____, as can the relationship between the fascicles and the associated ______
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parallel, vary, tendon
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What are the four different arrangement patters of fascicle arrangement or organization in skeletal muscles?
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1. Parallel
2. Convergent 3. Pennate 4. Circular (see Fig 9.14) |
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1. In a parallel muscle the fascicle are ______ to the longitudinal axis of the _____
2. In a convergent muscle, the muscle fibers are based over a ______ area, but all the fibers come together to a common ________ 3. In a pennate muscle, one or more ______ run through the body of the muscle, and the fascicles form an _________ angle to the tendon 4. In a circular muscle, the fibers are _________ arranged around and _______ or _______ |
1. parallel, muscle
2. broad, attachment site 3. tendons, oblique 4. concentrically, opening, recess |
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In a parallel muscle the individual muscle fibers may run the entire length of the muscle (True/False)
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True.
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1. In a parallel muscle muscle fibers may be interrupted by transverse, ________ pieces of ________ tissue at intervals along the length of the muscle?
2. Give an example of the above |
1. tendinous, connective
2. Rectus abdominis muscle on the anterior surface of the abdomen |
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Parallel muscles may exhibit a ______ or _____ arrangement, such as the supinator muscle of the forearm.
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Twisted or spiral
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What kind of muscle is the biceps brachii muscle of the arm based on muscle fiber arrangement?
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Parallel muscle
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Most of the skeletal muscles in the body are ________ muscles
a. parallel b. convergent c. pennate d. circular |
a. parallel
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The functional characteristics of a parallel muscle resemble that those of an individual ________
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muscle fiber
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The tendon of a parallel muscle extends from ______ to the central ______ of the muscle
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movable bone of the skeleton, body
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What is another name for the body of a skeletal muscle?
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Belly or gaster
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When the biceps brachii contracts, it gets ______ and the body ______ in diameter
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shorter, increases
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The bulge of the contracting biceps brachii can be see on the _____________ when the elbow is flexed
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anterior surface of the arm
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A skeletal muscle cell can contract effectively until has been shortened by ____ percent
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30
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Because the muscle fibers in a parallel muscle are parallel to the long axis of the muscle, when they contract together, the entire muscle shortens by ______
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the same amount
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1. In a parallel muscle the tension developed by a muscle can be estimated on the basis of the _______ of the resting muscle.
2. Why is this? |
1. cross-sectional area
2. This is because tension developed is directly proportional to the total number of myofibril which in a parallel muscle are distributed evenly through the sarcoplasm of each cell. |
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What is a slender band of collagen fibers called?
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Raphe
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The muscle fibers often spread out,like a fan or a broad triangle, with a ______ at the tip.
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tendon
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Give an example of a convergent muscle
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Pectoralis muscle of the chest
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What is a characteristic of a convergent muscle?
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This type of muscle has versatility; the direction of pull can be changed by stimulating only one group of muscle cells at any one time.
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1. When all groups of muscle fibers of a convergent muscle contract together, the pull as hard on the tendon as a parallel muscle of the same size (True/False)
2. Why? |
1. False. They do not pull as hard.
2. This is because the muscle fibers on opposite sides of the tendon pull in different directions rather than all pulling in the same direction. |
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Because they pull at an angle, contracting pennate muscle do not move their tendons as _____ as parallel muscles do.
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far
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A pennate muscle will contain more _____ than a parallel muscle of the same size. Therefore the contraction of a pennate muscle generates more _____ than that of a parallel muscle of the same size?
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muscle fibers, tension
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What are the three types of pennate muscles?
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1. Unipennate
2. Bipennate 3. Multipennate |
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In a pennate muscle
1. If all the muscle cells are found on the same side of the tendon, the muscle is ________ 2. If the muscle fibers are on both sides of of the tendon, the muscle is _______ 3. If the tendon branches within the muscle, the muscle is ______ |
1. Unipennate
2. Bipennate 3. Multipennate |
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What is an example of a
1. Unipennate muscle 2. Bipennate muscle 3. Multipennate muscle |
1. Extensor digitorum muscle of fingers
2. Rectus femoris muscle of thigh 3. Deltoid muscle of shoulder |
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What is another name for circular muscles?
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Sphincter
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When a circular muscle contracts, the diameter of the opening _____
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decreases
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What is the function of circular muscles?
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Guard entrances and exits if internal passageways such as the digestive and urinary tracts
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What is an example of a circular muscle?
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Orbicularis oris of mouth
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Each muscle begins at an ______, and ends at an _____, and contracts to produce a specific ______
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origin, insertion, action
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Typically the origin remains _____ and the insertion ____, or the origin is ______ to the insertion
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stationary, moves, proximal
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IF a muscle extends between a broad aponeurosis and a narrow tendon, the _____ is considered to be the origin, and the _____ is attached to the insertion.
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aponeurosis, tendon
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Almost all skeletal muscles either originate of insert on the _____
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skeleton
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What are two methods of describing actions? Give examples
|
1. References the bone region affected: the biceps brachii muscle is said to perform "flexion of the forearm"
2. Specifies the joint involved: the action of the biceps brachii muscle is described as "flexion of (or at) the elbow" |
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What are four types of muscles according to their primary action?
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1. Prime movers (agonists)
2. Antagonists 3. Synergists 4. Fixators |
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1. A prime mover, or agonist, is a muscle whose contraction is _________ for producing a particular movement
2. Antagonists are muscles who actions ______ that of agonists 3. When a synergist contracts, it _____ the prime mover in performing that action 4. When prime movers and antagonist contract simultaneously, they are acting as _______ |
1. chiefly responsible
2. oppose 3. assists 4. fixators |
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What is an example of the following?
1. Prime movers (agonists) 2. Synergists |
1. Biceps brachii is an example of a prime mover producing flexion at the elbow
2. Teres major assists the latissimus dorsi muscle in starting an inferior movement of the arm. |
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If the agonist produces flexion, the antagonist will produce ______
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extension
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Besides opposing motion of an agonist what is another role of an antagonist muscle.
|
When an agonist contracts to produce a particular movement, the corresponding antagonist will be stretched, but it will not relax completely. Instead its tension will be adjusted to control the speed of the movement and ensure its smoothness.
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What muscle acts as an antagonist to biceps brachii?
|
Triceps brachii muscle
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Synergists may provide additional _____ near the insertion or _____ the point of origin
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pull, stabilize
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In many cases the synergist muscles are most useful at the ____ of the movement, when the prime mover is ______ and its power is relatively _____
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start, stretched, low
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Flexors and extensors of the wrist act as fixators when they ______ simultaneously to ______ the wrist when muscles of the hand are contracted to firmly grasp an object in the fingers
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contract, stabilize
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Fixators ______ a joint and thereby create an ______ on which another muscle can act
|
stabilize, immovable base
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The names of most skeletal muscles provide clues to their identification (True/False)
|
True
|
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What are some criteria muscles are named according to?
|
1. Specific body regions
2. Orientation of muscle fibers 3. Specific or unusual features 4. Identification or origin and insertions 5. Primary functions |
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What is the meaning of the terms used to name muscles?
1. Rectus 2. Longus 3. Longissimus 4. Teres |
1. Rectus: straight
2. Longus: long 3. Longissimus: longest 4. Teres: long and round |
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What is the meaning of the terms used to name muscles?
1. Brevis 2. Magnus 3. Major 4. Maximus 5. Minor 6. Minimus |
1. Brevis: short
2. Magnus: big 3. Major: bigger 4. Maximus: biggest 5. Minor: smaller 6. Minimus: smallest |
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What are terms commonly used to name muscles that are
1. external or superficial 2. lying beneath or internal |
1. Externus or superficialis
2. Internus or profundus |
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Superficial muscles that position or stabilize an organ are called ____ muscles; those that operate within the organ are called ______ muscles
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extrinsic, intrinsic
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Rectus muscles are _______ muscles whose fibers generally run along the longitudinal axis of the body
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parallel
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_______ and _______ are directional indicators for muscles whose fibers run across or at an oblique angle to the longitudinal axis of the body.
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Transversus, oblique
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A _____ muscle has two tendons of origin, the _____ has three, and the _____ four.
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biceps, triceps, quadriceps
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The following names refer to muscles with look like what?
1. Trapezius 2. Deltoid 3. Rhomboideus 4. Orbicularis |
1. Trapezius: trapezoid
2. Deltoid: traingle 3. Rhomboideus: rhomboid 4. Orbicularis: circle |
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1. The names of many muscles identify their origins and insertion. In such cases, the first part of the name indicates the _____ and the second part the ____
2. Give an example of the above |
1. origin, insertion
2. Genioglossus muscle originates at chin (geneion) and inserts in the tongue (glossus) |
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1. What is an example of a muscle named after the specific movements associated with special occupations or habits?
2. Buccinator in buccinator muscle translates as ______ 3. Risor in ristorius muscle means |
1. Sartorius muscle; active when crossing legs and derived from sartor, the Latin word for "tailor" since before sewing machines tailors sat cross-legged on the floor.
2. trumpet player 3. laughter |
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What are two muscles that do not include the term muscle in their names?
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1. Platysma
2. Diaphragm |
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When a muscle is attached to the skeleton, the nature and site of the connection will determine the ______, ______, and _______ of the movement produced.
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force, speed, range
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A ______ is a rigid structure---such as a board, a crowbar, or a bone---that moves on a fixed point called the _____
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lever, fulcrum
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Levers can changer the _____ of an applied force, the _____ and ____ of movement produced by a force, and the _____ of a force
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direction, distance, speed, strength
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What are the three classes of levers found in the human body?
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1. First-class lever
2. Second-class lever 3. Third-class lever |
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The seesaw is an example of a _______ lever
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first-class
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1. In a first-class lever the fulcrum lies ______ the applied force and the resistance
2. In a second-class lever, the _______ is located between the _____ and the ______ 3. In a third-class lever system, a ______ is applied between the _______ and the _______ |
1. between
2. resistance, applied force, fulcrum 3. force, resistance, fulcrum (see Fig 9.15) |
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1. There are many example of first-class levers in the body (True/False)
2. Give one example |
1. False
2. Muscles that extend the neck |
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What is a familiar example of second-class lever
1. outside the body 2. inside the body |
1. wheelbarrow
2. Calf muscles performing plantar flexion |
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In a second-class lever system the applied force is always ______ from the fulcrum than the resistance, therefore a _______ force can balance a ______ weight. In other words the force is ____.
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farther, small, larger, magnified
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In a second-class lever system the resistance moves more _____ and covers a _____ distance compared to the applied force
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slowly, shorter
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What is the most common lever system in the body?
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Third-class lever system
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In third class levers speed and distance travelled are increased at the expense of the ____. For example in the biceps brachii muscle that flexes the elbow the resistance is six times farther from the fulcrum than the applied force. The biceps brachii muscle can develop an effective force of 180 kg, which now will be reduced from 180 kg to ___ kg. However, the distance traveled and the speed of movement are _____ by the same ratio (6:1): The resistance travels 45 cm while the insertion point moves only ____ cm
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applied force, 30, increased, 7.5
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Every muscle operates as part of a lever system (True/False)
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False
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The presence of levers provides speed and versatility far in excess of what we would predict on the basis of muscle physiology alone. Skeletal muscle cells resemble one another closely, and their abilities to contract and generate tension are quite _____
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similar
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Consider a skeletal muscle that can contract in 500 ms and shorten 1 cm while exerting a 10-kg pull. Without using a lever, this muscle would be performing efficiently only when moving a ____ kg weight a distance of ___ cm. But by using a lever, the same muscle operating at the same efficiency could move 20 kg a distance of ____ cm, _____ kg a distance of 2 cm, or ____ kg a distance of 10 cm. Thus, the lever system design produces the maximum movements with the greatest efficiency.
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10, 1, 0.5, 5, 1
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Mechanical pulleys are often used to _____ of a force in order to accomplish a task more easily and efficiently.
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change the direction
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In the body, tendons act like lines that convey the _____ produced by muscle contraction. The path taken by the tendons may be changed by the presence of ______ or ______
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forces, bones, bony processes
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Bony structures that change the direction of applied forced are called _____
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anatomical pulleys
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What is an example of an anatomical pulley that is essential to the function of the fibularis longus which is producing plantar flexion at the ankle?
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Lateral malleolus
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What is another example of an anatomical pulley that is essential to the extension at the knee produced by the quadriceps femoris?
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The patella
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For muscles attach to the patella by the quadriceps tendon. The patella is, in turn, attached to the tibial tuberosity by the patellar ligament. The quadriceps tendon pulls on the patella in one direction throughout the movements, but the direction of force applied to the tibia by the patellar ligament __________ as the movement proceeds
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Changes constantly.
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As the body ages, there is a general reduction in the ____ and ____ of all muscle tissues.
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size, power
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What are the effects of aging on the muscular system?
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1. Skeletal muscle fibers become smaller in diameter
2. Skeletal muscles become smaller in diameter and less elastic 3. Tolerance for exercise decreases 4. Ability to recover from muscular injuries decreases |
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1. The reduction in size of muscle due to aging reflects primarily a decrease in the number of ________. In addition, the muscle fibers contain less ____, ____, and ____.
2. The overall effect is a reduction in muscle ____ and _____ and a tendency to _____ rapidly |
1. myofibrils, ATP, glycogen reserves, myoglobin
2. strength, endurance, fatigue |
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Because cardiovascular performance also decreases with age, _____ to active muscles does not increase with exercise as rapidly as it does in younger people.
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blood flow
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Aging skeletal muscle develop increasing amounts of fibrous connective tissue, a process called _____
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fibrosis
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Fibrosis makes the muscle less ______, and the collagen fibers restrict ______ and ______
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flexible, movement, circulation
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A lower tolerance for exercise in an aging individual results in part from the tendency for rapid _____ and in part from the reduction in the ability to eliminate the _____ generated during muscular contraction
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fatigue, heat
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The number of _____ cells steadily decreases with age, and the amount of _____ tissue increases. As result when injury occurs, repair capabilities are limited, and _____ tissue formation is the usual result
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myosatellite, fibrous, scar
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The _____ of decline in muscular performance is the same in all individuals, regardless of their exercise patterns or lifestyle. Therefore, to be in good shape later in life, one must be in very good shape _______
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rate, early in life
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Regular exercise helps _____ body weight, ____ bones, and generally improves the quality of life at all ages
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control, strengthens
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Extreme exercise in the elderly may lead to problems with _____, ____ and _____
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tendons, bones, joints
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Exercise prolongs life expectancy (True/False)
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False. There is no clear evidence of this.
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What does the name flexor digitorum longus tell you about this muscle?
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This is a long muscle that flexes the joints of the finger.
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Describe the difference between the origin and insertion of a muscle.
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Each muscle begins at an origin, which typically remains stationary, and ends at an insertion, which is the part of the muscle that moves during a contraction.
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What type of a muscle is a synergist?
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It contracts to assist the prime mover in performing a specific action.
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What is the difference between major and minor designations for a muscle?
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Major is used to describe muscles that are bigger, whereas minor is used to describe muscles that are smaller.
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What is trichinosis? What are the symptoms?
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Infection by the parasitic nematode Trichinella spiralis that invade skeletal muscle tissues and create small pockets within the perimysium and endomysium causing the following symptoms: diarrhea, weakness, muscle pain
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Trichinella larvae are common in flesh of what animals?
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1. Pigs
2. Horses 3. Dogs 4. Other mammals |
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What is the life cycle of Trichinella spiralis in humans?
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1. Human ingests cyst in under-cooked pork
2. Stomach acid dissolves cyst cover, releasing worms 3. Females release larvae into lymphatic and blood vessels 4. Larvae migrate to muscle and encyst |
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An estimated 1,5 million Americans carry Tichinella in their muscles, and up to 300,000 new infections occur each year. The mortality rate for people who have symptoms severe enough to require treatment is approximately ____ percent
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1
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