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57 Cards in this Set
- Front
- Back
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Type of Muscles |
Cardiac, Skeletal, and Smooth (lines organs |
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What are Characteristics of muscles? |
-Muscle cells are elongated -Muscles contraction is dependent on the Microfilaments (actin and myosin) - |
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What are structures of Muscles cells |
Sarcolemma- cell membrane of a muscle cell Sarcoplasm- cytoplasm of a muscle cell |
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What are Characteristics of the muscle cells |
Escitability: the ability and receive and respond to stimuli Contractility: ability to shorten Extensibility: ability to stretch Elasticity: ability to recoil to resting length |
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Cardiac cells contain: |
-Sarcopasmic Reticulum, T-Tubules and Mitochondria |
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Cardiac cell traits |
1-2 nuclei -Network of fibers, disks -Contracts at a rhytmic , steady pace -Self Excites
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Skeletal Muscle Characteristics |
-Attached to bones -Multinuclate fibers, long and thin with sarcomeres -Contracts rapidly but tires easily |
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Functions of Skeletal Muscle |
-Produce Movement -Maintain Body Posture and Body Position -Support Soft Tissues -Gaurds Entrances adn Exits -Body Temperature -Store Nutrient Reserves |
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Components of Connective Tissue |
Fascia: sheet of fibrous tissue (split up into superficial and Deep) Tendon-Dense regular connective tissure that attaches muscle to bone |
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Parts of muscle |
-Organ -Fascicle (bundle of fibers) -Fiber |
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Traits of Epimysium? |
Surrounds entire muscle -Seperates Muscles from Tissures -Connected to deep fascia Collagen fibers |
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Traits of Perimysium |
Surrounds Fascicles -Connects blood vessels -Collagen and elastic fibers |
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Endomysium |
Delicate, elastic tissure -Surrounds individual cells -Contain Capillary networks, Satellite cells, and nerve fibers |
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Traits of Sarcoplasmic Reticulum |
-Network of Smooth Endoplasmic Reticulum surrounding each Myofibril -Pais of terminal cisternae form permendicular -Regulates calcium levels -high levels of calcium |
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Traits of T Tibules |
-Continuous witht he sarcolemma -Penetrate the cell's interior at each A band-I band junction W |
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What is a triad |
Terminal cisternae- dialted ends of SR Sit on both sides of a T tubule Triad= TC-T-TC |
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Muscles Contraction Occurs when |
-SR releases CA into Sarcoplasm -Signal rapidly distributed by T tubules |
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Myofibrils |
-physically and functionally discrete parts of a muscle -Shorten to produce muscle contractions -Composed of myofiliments (actina nd myosin) |
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What is the Sarcomere |
-The region of a myofibril between two successive -Smallest contractile unit of muscle fiber -Composed of thick and thin myofilaments |
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Parts of the Sarcomere |
-Thick and thin filaments (myosin and actin) -Z disc -H zone -M line |
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The Anatomy of Muscles |
Muscles, Muscle fibers, Fascicles (long cell), Myofibrils, myofilaments make up myofibrils. |
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Structural Muscle Proteins |
Nebulin, Titin, Dystrophin, Myomesin |
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Regulatory Protein |
Troponin, tropomyosin |
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Contractile Protein |
Actin and Myosin |
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Traits of Nebulin? |
Holds the helix of the actin in place (structural) |
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What is Titin |
Holds the Myosin in place and organizes the A band -Helps the muscles to resist excessive stretching and helps in muscular recoil (structural) |
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Dystophin |
A cytoplasmic protein that links the cytoskeleton to extracellular matris stablizes the sarcolemma (structural) |
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Myomesin |
A line of the sarcomere; anchors myosin in the A band (structural) |
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What are the regular Proteins? |
(parts of the thin filament along with actin) -Troponin and Tropomyosin |
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What is Troponin |
-Comples of 3 globular proteins -One binds actin, one binds tropomyosin, one binds calcium. |
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Tropomysoin |
-Rod-shaped protein -Covers myosin-binding site on actin |
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What are the contractile Proteins |
Actin and Myosin |
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What are Actin |
-Coiled helical structure -Myosin-binding site on each bead of actin (smaller) |
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Myosin |
Rod like tail that ends in the two globular heads -Cross bridges (thick) |
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Overview of mycles contraction |
-Pulls on attached tendon -Creates tension -tension applied to object pulls object towards source of tension -Must overcome resistance |
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How is muscle contraction controled? |
Activated by somatic motor neurons -neurons stimulate of sarcolemma |
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What is Excitation contraction coupling? |
The stimulation of Sarcolema triggers 1. Ca released from SR 2. CA trigger interactions between actin and myosin 3. Ca trigger interactions between actin and myosin 4. Muscle fibers contract 5. Filament interactions produce active tension
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Sliding Filaments Theory |
Muscle contraction invovles the sliding moement of the thin filaments past the thick filaments sliding continues but does not overlap |
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Where does the activation of contraction take place? |
at a neutomuscular junction, which consist of: 1. Generation of propagation of an action potential along the sarcolemma 2. Final trigger : a brief rise in tntracellular Ca levels |
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Details of Neurotransmitter |
-Chemical substance is released from a nueron -Causes stimulation of the sarcolemma -EX. Acetylcholine: primary neurotransmitter in motor neurons to skeletal muscles |
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What is the Synaptic terminal? |
Where the Nueron meets the muscle -Transmits ACh (look at picture) |
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Synaptic cleft |
gel filled space between the Synaptic terminal and muscle |
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Motor end plate |
Region on sarcolemma that contain membrane receptors for ACh |
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What are the events that take place at the Nuetomuscular Junction |
1.Nerve impulse arrives at axon terminal 2. ACh is released and binds with receptors on the sarcolemma 3. Electrical events lead to the generation of an action potential |
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Excitation- Contraction Coupling |
The neron excites the sarcolema, the muscles can than begin to contract. |
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The steps of Excitation- contraction Coupling |
1.Ca++ binds to the Ca receptor on troponin 2. Tis moves the tropomyosin strand out of the way 3. Allowind cross bridges between actin and myosin heads to form Contraction than begins Look at pictures |
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Contraction Cycle |
-Myosin head is "energized" -Myosin head functions as an ATPase -ATPase splits bounds to myosin head -Energized Myosin head is "cocked" |
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How does the myosin become exposed? |
-Ca eneters sarcoplasm -Ca binds to troponin -Troponin changes shape and moves tropomyosin -Myosin binding site exposed on actin |
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How is the Cross bridge formed? |
1. energized myosin head binds to myosin binding site on actin 2. Cross- bridge formed |
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The "Power Stroke" |
1. Resting sarcomere, myosin heads point away from M line (cocked) 2.. Formation of cross-bridge causes release of stored energy from myosin head 3. Myosin head pivots towards M line (power stroke) 4. ADP and P released from Myosin |
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The Detachment of Cross- bridge |
1. New Atp binds to empty mysin head 2. Cross bridge is broken 3. Exposed Myosin bidning site on actin ready to bind another myosin head. |
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Reactivatin of Myosin |
Myosin head ATPase splits (ATP > ADP+ P) Energy Recocks myosin head *This Cycle is repeared several time/second*: As long as Ca levels are high and ATP is sufficient
Each Power Stroke Shortens Sarcomere 1% |
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Relaxation of the Muscle |
Ca levels return to normal (active Transport into ECF and SR
Everything for back to the way it waso |
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Steps in E-C Coupling |
1. Action potential is propagated along the sarcolemma and down the T tubules 2. Calcium ions are realised 3. Calcium binds to troponin and removes and blocking action of tropomyosin 4. Contraction begins |
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Muscles Contraction |
The principles applies to contraction of a whol muscle 1. Contraction produces tension the force exerts the load or object to be moved 2. COntractin does not always shorten a muscles : Isometric vs. Isotonic contraction 3. Force and duration of contraction vary in responce stimuli of different frequencies and intensities |
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What is a muscle twitch |
Responce of a motor units to a single, brief threshold stimulus |
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What does Tension Production depend on? |
-Number of muscles recruited -Size of recruited muscles -Fiber's resting length at time of stimulatyion and degree of overlap -Frequency of stimulation |
