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264 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Are muscle tissues highly cellular or cellular?
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highly cellular
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slide 2
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Are muscle tissues poorly vascularized or well vascularized?
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well vascularized
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slide 2
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What do muscle tissues transform?
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chemical energy (ATP) into directed mechanical energy
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slide 2
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What are three prefixes referring to muscle?
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myo, mys, sarco
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slide 2
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What are the principal functions of muscle tissue?
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- producing movement
- maintaining posture and body position - stabilizing joints - generating heat |
slide 3
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What is excitability?
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the ability to receive and respond to stimuli
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slide 4
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What is contractility?
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the ability to shorten when stimulated
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slide 4
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What is extensibility?
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the ability to be stretched
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slide 4
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What is elasticity?
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the ability to recoil to resting length
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slide 4
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What are the three types of muscle tissue?
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- skeletal muscle
- cardiac muscle - smooth muscle |
slide 5
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What specific tissue type is best described :
" cells are long and cylindrical " |
skeletal muscle tissue
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What specific tissue type is best described:
" cells are multinucleate " |
skeletal muscle tissue
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Do skeletal muscle cells have striations?
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yes
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_______ and ________ muscle cells have striations.
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skeletal ; cardiac
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What specific tissue type is best described:
" attached to bones and skin " |
skeletal muscle tissue
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What specific tissue type is best described:
" involved in voluntary movement/conscious control " |
skeletal muscle tissue
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Skeletal muscle cells are also called _______.
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fibers
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Skeletal muscle tissue cells are ____nucleate.
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multinucleate
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______ muscle tissue cells are located only in the heart.
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cardiac
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Cardiac muscle tissue cells are involved in ____________ movement.
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involuntary
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Cardiac muscle tissue cells are _____nucleate.
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uninucleate
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What specific tissue type is described:
" cells are branched " |
cardiac muscle tissue
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What specific tissue type is described:
" not striated " |
smooth muscle tissue
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What specific tissue type is described:
" cells are spindle-shaped " |
smooth muscle tissue
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What specific tissue type is described:
" in the walls of hollow organs, like the stomach, urinary ladder, and respiratory passages " |
smooth muscle tissue
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Smooth muscle tissue is involved in _________ movement.
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involuntary
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Skeletal muscle is characterized as an _______.
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organ
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Why is skeletal muscle characterized as an organ?
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It is made up of several kinds of tissues, like:
- nerve and blood supply - connective tissue - attachments - skeletal muscle fibers |
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Why are skeletal muscle cells associated with connective tissue?
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Since contracting muscle fibers are not as effective if they work in isolation
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Explain how a contracting unit is formed.
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Each fiber is bound to adjacent fibers to form bundles, and bundles are bound to adjacent bundles to form a contracting unit.
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Skeletal muscles have sheaths of connective tissue. What are the sheaths of connective issue called?
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- endomysium
- perimysium - epimysium |
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Skeletal muscles have sheaths of _________.
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connective tissue
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What term is described:
" the most internal connective sheath of skeletal muscle " |
endomysium
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What sheath of connective tissue is described:
" surrounds individual fibers " |
endomysium
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What sheath of connective tissue is best described:
" consists of fine areolar connective tissue " |
endomysium
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What sheath of connective tissue is best described:
" binds fibers into fascicles " |
perimysium
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What are fascicles?
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groups of fibers
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What sheath of connective tissue is best described:
" consists of fibrous connective tissue " |
perimysium
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What connective tissue sheath is best described:
" surrounds the entire muscle " |
epimysium
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What connective tissue sheath is best described:
" consists of dense irregular connective tissue " |
epimysium
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What connective tissue sheath is best described:
" the most external sheath " |
epimysium
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What term is described:
" fibrous connective tissue that covers muscles and attaches to skin " |
fascia
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What is fascia?
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fibrous connective tissue that covers muscles and attaches to skin
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What does superficial fascia do?
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secures skin to underlying structures
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_____ fascia is described:
" secures skin to underlying structures " |
superficial fascia
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_____ fascia is described:
" blends with epimysium " |
deep fascia
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Deep fascia blends with _______.
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epimysium
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_____ fascia is described:
" surrounds adjacent muscles " |
deep fascia
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____ fascia binds adjacent muscles in functional groups.
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deep fascia
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Deep fascia binds adjacent muscles in _________.
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functional groups
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What are the two types of fascia?
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superficial and deep
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Skeletal muscle has a _______ rate of metabolic activity.
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high
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Since skeletal muscle has a high rate of metabolic activity, it requires what to receive oxygen and nutrients, and to eliminate waste products.
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blood vessels
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What is the function of the blood vessels of skeletal muscle?
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to give oxygen and nutrients to skeletal muscle and to eliminate waste products
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Each muscle is served by one or more what?
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arteries, veins, and blood vessels
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Capillaries of skeletal muscle are located in __________.
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endomysium
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What connective tissue sheath is described:
" contains capillaries of skeletal muscle " |
endomysium
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Muscles attach to a bone on each end via _________.
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tendons
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Tendons are made up of what type of tissue?
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dense regular connective tissue
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Muscle attachments may be either _______ or _________.
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direct ; indirect
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The following statement describes __________ muscle attachments:
" epimysium of muscle is fused to the periosteum of bone or perichondrium of cartilage " |
direct
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In direct attachments, the ______ of muscle is fused to the periosteum of bone or perichondrium of cartilage.
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epimysium
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In direct attachments, the epimysium of muscle is fused to what?
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periosteum of bone or perichondrium of cartilage
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The following statement describes ________ attachment:
" connective tissue wrappings extend beyond the muscle as a ropelike tendon or sheetlike aponeurosis " |
indirect
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_______ attachment makes use of a tendon.
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indirect
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______ attachment makes use of sheetlike aponeurosis.
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indirect
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What is retinaculum?
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a group of tendons bound by connective tissue
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Muscle is covered externally by __________.
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epimysium
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What term is described by the following statement:
" consists of hundreds to thousands of muscle cells, plus connective tissue wrappings, blood vessels, and nerve fibers " |
muscle (organ)
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What term is described by the following:
" a discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath " |
fascicle
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Fascicle is surrounded by __________.
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perimysium
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What term is best described by the following:
" an elongated multinucleate cell; it has a banded(striated) appearance " |
a muscle fiber (cell)
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A muscle fiber is surrounded by __________.
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endomysium
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What term is best described by the following statement:
" plasma membrane of muscle cell " |
sarcolemma
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What term is best described by the following statement:
" cytoplasm of muscle cell " |
sarcoplasm
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What term is best described by the following statement:
" granules of stored glycogen " |
glycosomes
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What term is best described by the following statement:
" red pigment that stores oxygen " |
myoglobin
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What term is best described by the following statement:
" ER network of muscle cell " |
sarcoplasmic reticulum
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What do transverse (T) tubules do?
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conduct nerve impulses
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What are transverse (T) tubules?
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sarcolemma extending into the cell
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Explain the relationship between myofibrils and myofilaments.
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Myfilaments make up myofibrils
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What term is best described by the following statement:
" densely packed, rodlike bundles of filaments " |
myofibrils
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There are two types of myofilaments. What are they?
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thick and thin
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thick myofilaments contain _______.
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myosin
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thin myofilaments contain ________.
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actin
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Myofibrils and myofilaments run _______ to cell's length.
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parallel
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80% of muscle fiber cell volume is made up of what?
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myofibrils and myofilaments
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Describe the myofilament arrangement in a muscle fiber cell.
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perfectly aligned repeating series of dark and light bands along the myofibril's length.
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Dark ______ bands
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A
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Light ______ bands
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I
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Due to the myofilament arrangement, muscle cells exhibit what?
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striations
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The arrangement of thick and thin myofilaments between a pair of Z lines forms a repeating pattern that serves as the ____________.
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sarcomere
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What is the sarcomere?
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the basic unit of skeletal muscle contraction
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The arrangement of thick and thin myofilaments between a pair of ___________ forms a repeating pattern that serves as the sarcomere (basic unit of skeletal muscle contraction).
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Z lines
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The smallest contractile element of a skeletal muscle fiber is a ___________.
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sarcomere
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The region of myofibril between two successive Z discs is ___________.
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a sarcomere
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A sarcomere is a region of myofibril between two what?
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successive Z discs?
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The sarcomere is composed of what?
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thick and thin myofilaments, made of contractile proteins
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______ filaments run the entire length of an A band
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thick
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_______ filaments run the entire length of an I band and part way into the A band.
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thin
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thin filaments run the entire length of an _____ band and part way into the _____ band.
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I ; A
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The A band has an ____ zone.
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H zone
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The A band has an H zone that is what?
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a lighter region in midsection where filaments do not overlap
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What part of a sarcomere is described:
" a lighter region in midsection where filaments do not overlap " |
H zone of the A band
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The A band has an M line that is what?
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a dark band that vertically bisects the H zone; holds adjacent thick filaments together
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The H zone and M line are part of the what?
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A band
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The Z disc is part of the what?
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I band
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What term is best described:
" holds adjacent thick filaments together " |
M line
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What term is best described:
" dark band that vertically bisects the H zone" |
M line
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What term is best described:
" darker midline that anchors thin filaments " |
Z disc
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What term is best described:
" connects myofibrils to one another " |
Z disc
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Thick filaments run where?
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the entire length of an A band
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Thin filaments run where?
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the entire length of an I band and pat way into an A band
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What is sarcoplasmic reticulum (SR)?
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specialized ER of muscle cells
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What term is best described:
" interconnecting network of smooth ER tubules surrounding each myofibril " |
Sarcoplasmic reticulum
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Sarcoplasmic reticulum is an interconnecting network of _________ surrounding each myofibril.
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smooth ER tubules
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Sarcoplasmic reticulum is an interconnecting network of smooth ER tubules surrounding what?
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each myofibril
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Another term for terminal cisternae is what?
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sarcoplasmic reticulum tubules (SR tubules)
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What do terminal cisternae (SR tubules) form?
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perpendicular cross channels at the A band-I band junctions
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What forms perpendicular cross channels at the A band-I band junctions?
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terminal cisternae (SR tubules)
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What term is best described:
" functions in the regulation of intracellular calcium levels " |
Sarcoplasmic reticulum
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Sarcoplasmic reticulum functions in the regulation of what?
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intracellular calcium levels
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What term is best described:
" elongated tubules of sarcolemma protruding into cell interior at A band- I band junctions " |
T tubules
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What do T tubules do?
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conduct nerve impulses from sarcolemma to every sarcomere
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What term is best described by the following:
" conduct nerve impulses from sarcolemma to every sarcomere " |
T tubules
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T tubules conduct nerve impulses from sarcolemma to every sarcomere. This ensures what?
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that every myofibril in a muscle fiber contracts at the same time
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Every myofibril in a muscle fiber contracts at the same time because ....
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T tubules conduct nerve impulses from sarcolemma to every sarcomere
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What are triads?
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successive groupings of T tubles flanked by paired terminal cisternae
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_________ conduct impulses deep into the muscle fiber.
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T tubules
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What term is best described :
" integral proteins protrude into the intermembrane space from T tubule and SR cisternae membranes " |
triad
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Integral proteins protrude into the intermembrane space from ________ and _________.
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T tubules ; SR cisternae membranes
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_________ proteins act as voltage sensors.
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T tubule
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T tubule proteins act as what?
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voltage sensors
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What are SR foot proteins?
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gated channels that regulate calcium release from the SR cisternae
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What is contraction?
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the generation of force
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True or false: contraction always causes shortening of the fiber
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false because contraction does not necessarily cause shortening of the fiber
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True or false: contraction does not necessarily cause shortening of the fiber
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true
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When does shortening of the fiber occur?
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when tension generated by cross bridges on the thin filaments exceeds forces opposing shortening
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When tension generated by cross bridges on the thin filaments exceeds forces opposing shortening what happens?
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shortening occurs
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In the relaxed state, what happens to thin and thick filaments?
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thin and thick filaments overlap only slightly
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thin and thick filaments overlap only slightly in what state?
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relaxed state
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During contraction, what happens to thick and thin filaments?
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myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments toward the M line
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During contraction, ______ heads on thick filaments bind to ______ on thin filaments, propelling the thin filaments towards the M line
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myosin ; actin
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During contraction, myosin heads on thick filaments bind to actin on thin filaments, propelling the _______ filaments toward the M line
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thin
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During contraction, myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments towards what?
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the M line
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During _______ myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments towards the M line
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contraction
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_______ fibers slide past the ______ filaments, so that actin and myosin overlap during contraction
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thin ; thick
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Thin fibers slide past the thick filaments, so that ______ and ______ overlap during contraction.
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actin ; myosin
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Describe how thin fibers slide past the thick filaments during contraction
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- I band shortens
- distance between Z bands decreases - H zone disappears - Contiguous A bands move closer together but do not change in length |
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What has to happen for the muscle cells to shorten, and for the whole muscle to shorten?
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H zones shorten and disappear, causing the sarcomeres to shorten
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What happens to I bands during contraction?
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I bands shorten
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What happens to A bands during contraction?
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they move closer together but do NOT change length
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What happens to Z bands during contraction?
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the distance between Z bands decreases
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What happens to H zones during contraction?
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they shorten and disappear
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What is the "main step" of contraction that causes sarcomeres to shorten?
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H zones shorten and disappear
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What are the two requirements for skeletal muscle contraction?
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1. activation
2. excitation-contraction coupling |
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What is activation?
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neural stimulation at a neuromuscular junction
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What is excitation-contraction coupling?
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- generation and propagation of an action potential along the sarcolemma
- final trigger: a brief rise in intracellular calcium levels |
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What is the final trigger of skeletal muscle contraction?
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a brief rise in intracellular calcium levels
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In order for skeletal muscle to contract, an __________ must be generated and propogated along the sarcolemma.
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action potential
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In order for skeletal muscle to contract an action potential must be generated and propogated along the ________.
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sarcolemma
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In order for skeletal muscle to contract, what has to happen first?
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activation = neural stimulation at a neuromuscular junction
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Skeletal muscles are stimulated by what?
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somatic motor neurons
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Somatic motor neurons stimulate what?
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skeletal muscle
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Axons of motor neurons travel from ___________ via nerves to _________.
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nervous system ; skeletal muscles
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Axons of motor neurons travel from the central nervous system via _______ to skeletal muscles.
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nerves
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Each axon forms what as it enters a muscle?
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several branches
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________ of motor neurons travel from the central nervous system to skeletal muscles.
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Axons
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Motor end plates are where axons contact ________.
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sarcolemma
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Motor end plates are where ______ contact sarcolemma.
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axons
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__________ are where axons contact sarcolemma.
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Motor end plates
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Motor end plates form a ___________ with a single muscle fiber
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neuromuscular junction
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Motor end plates form a neuromuscular junction with a ____________.
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single muscle fiber
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__________ form a neuromuscular junction with a single muscle fiber.
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Motor end plates
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What term is best described by the following:
" situated midway along the length of a muscle fiber " |
neuromuscular junction
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A neuromuscular junction is situated where?
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midway along the length of a muscle fiber
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The axon terminal and muscle fiber are separated by a space called the _________.
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synaptic cleft
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What is the synaptic cleft?
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a space that separates the axon terminal and muscle fiber.
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The __________ and _________ are separated by a space called the synaptic cleft.
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axon terminal ; muscle fiber
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Synaptic vesicles of axon terminal contain what neurotransmitter?
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acetylcholine (ACh)
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________ of axon terminals contain the neurotransmitter acetylcholine (ACh)
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Synaptic vesicles
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Synaptic vesicles of ___________ contain the neurotransmitter acetylcholine.
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axon terminals
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Acetylcholine is a type of ________.
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neurotransmitter
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Junctional folds of the sarcolemma contain what?
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acetylcholine receptors
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_________ of the sarcolemma contain acetylcholine receptors.
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junctional fods
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Junctional folds of the _______ contain the ACh receptors.
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sarcolemma
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What is the sliding filament theory of contraction?
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during contraction, the thin filaments slide past the thick ones so that the actin and myosin filaments overlap to a greater degree.
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In a relaxed muscle fiber, what happens to the thick and thin filaments?
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they overlap only at the ends of the A bands.
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Thick and thin filaments overlap only at the ends of the A bands when?
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when they are relaxed
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Describe the events in detail that occur at the neuromuscular junction
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- The nerve impulse arrives at the axon terminal
- voltage gated calcium channels allow calcium to flood in side the axon terminal - the presence of calcium causes ACh to be released into the synaptic cleft - ACh diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma - ACh binding opens ion channels that allow sodium into the muscle and potassium out of the fiber. Since more sodium diffuses in than K diffuses out, the muscle becomes slightly less negative, known as depolarization. - Since the inside of the muscle now has less potassium, this "attracts" more potassium to diffuse back into the muscle....which is repolarization. - ACh effects are terminated. |
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The very first event at the neuromuscular junction is what?
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a nerve impulse (axon potential ) arrives at the axon terminal of a motor neuron
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After an axon potential arrives at the axon terminal, what happens at the neuromuscular junction?
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AcH is released into the synaptic cleft
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After AcH is released into the synaptic cleft, what happens at the neuromuscular junction?
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AcH binds to receptors on the sarcolemma
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After ACh binds to receptors on the sarcolemma, what happens at the neuromuscular junction? (briefly).
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Electrical events lead to the generation of muscle contraction....
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After a muscle contraction has been generated, what happens at the neuromuscular junction?
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ACh effects are terminated.
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What process is best described by the following:
" sequence of events by which transmission of an AP along the sarcolemma leads to the sliding of myofilaments" |
excitation-contraction coupling
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Transmission of the action potential along the sarcolemma leads to what?
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sliding of the filaments
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what leads to sliding of the filaments?
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transmission of the action potential along the sarcolemma
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transmission of the ________ along the sarcolemma leads to sliding of the filaments
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action potential
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transmission of the action potential along the _________ leads to sliding of the filaments
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sarcolemma
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After the sliding of the filaments, the action potential goes from the sarcolemma to what?
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T tubules
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After the sliding of the filaments, the action potential goes from what to the T tubules?
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sarcolemma
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voltage sensitive proteins simulate what release from the sarcoplasmic reticulum?
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calcium
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_______stimulate calcium release from the sarcoplasmic reticulum
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voltage sensitive proteins
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voltage sensitive proteins stimulate calcium release from what?
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sarcoplasmic reticulum
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What ULTIMATELY causes filament sliding?
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calcium release
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what ULTIMATELY causes muscle contraction?
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filament sliding/calcium release
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What is a motor unit?
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a motor neuron and the group of muscle cells it stimulates
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What term describes the following:
" a motor neuron and the group of muscle cells it stimulates " |
motor unit
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Axons of motor neurons extend from ___________ to muscle.
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spinal cord
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Axons of motor neurons extend from the spinal cord to ________.
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muscle
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Axons of motor neurons extend from the ________ to ________.
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spinal cord; muscle
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The nerve-muscle functional unit is known as the what?
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motor unit
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Axons of ________ extend from the spinal cord to muscle.
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motor neurons
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_______ of motor neurons extend from the spinal cord to muscle.
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Axons
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In the muscle, each axon divides into a number of ___________.
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axon terminals
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In the muscle, each ________ divides into a number of axon terminals.
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axon
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In the muscle, each axon divides into a number of axon terminals that form ____________ with muscle fibers.
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neuromuscular junctions.
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In the muscle, each axon divides into a number of axon terminals that form neuromuscular junctions with ___________.
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muscle fibers
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Axon terminals form neuromuscular junctions with __________.
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muscle fibers
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Axon terminals form ______________ with muscle fibers.
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neuromuscular junctions
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________ form neuromuscular junctions with muscle fibers.
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Axon terminals
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When a motor neuron fires,what happens to all the muscle fibers it innervates?
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contract
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When do all the muscle fibers that innervate a motor neuron contract?
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When a motor neuron fires/releases AP
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Muscle fibers from a motor unit are spread throughout the muscle so that a single motor unit causes what?
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weak contraction of entire muscle
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muscle fibers from a motor unit are _________________ so that a single motor unit causes weak contraction of an entire muscle.
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spread out throughout the muscle
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muscle fibers from a motor unit are spread throughout the muscle so that what can cause weak contraction of an entire muscle?
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a single motor unit
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Motor units in a muscle usually contract asynchronously. Why?
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to help prevent fatigure
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Motor units in a muscle usually contract ____________ to help prevent fatigue.
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asynchronously
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the number of motor units activated is based on what?
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the magnitude of the task; greater task = more motor units.
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muscles that control fine movements have ______ motor units.
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small #
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muscles that control weight bearing movements have ______ motor units
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large #
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What's a muscle twitch?
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Response of a motor unit to a single firing of its motor neuron
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What term is described by the following:
"response of a motor unit to a single firing of its motor neuron " |
muscle twitch
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What term is best described by the following statement:
" simplest contraction observable " |
muscle twitch
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What term is best described by the following statement:
" graphic recording of contractile activity" |
myogram
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What is a myogram?
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a graphic recording of contractile activity
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A myogram is a graphic recording of _________ activity.
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contractile
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What are the three phases of a muscle twitch?
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latent period, period of contraction, period of relaxation
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What phase of a muscle twitch is best described by the following statement:
" first few milliseconds following stimulation " |
Latent period
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What phase of a muscle twitch is best described by the following statement:
" muscle tension increases but no response seen on myogram " |
latent period
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During the latent period of a muscle twitch, muscle tension _______ but there is no response seen on myogram.
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increases
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During the latent period of a muscle twitch, muscle tension increases. What is seen on a myogram?
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no response seen on a myogram, despite muscle tension increase!
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What phase of a muscle twitch is best described by the following statement:
" 10-100 ms " |
period of contraction
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What phase of a muscle twitch is described by the following:
" If tension is great enough to overcome resistance of load, the muscle shortens" |
period of contraction
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During the period of contraction phase of a muscle twitch, if tension is great enough to overcome resistance of the load, what happens?
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muscle shortens
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During the period of contraction phase of a muscle twitch, if tension is great enough to overcome __________, the muscle shortens.
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resistance of the load
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During the period of contraction phase of a muscle twitch, what has to happen for the muscle to shorten?
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Tension must be great enough to overcome resistance of the load.
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What phase of a muscle twitch is described by the following:
" Contractile force declines and muscle tension decreases to 0." |
period of relaxation
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During a period of relaxation of a muscle twitch, contractile force declines. What happens to muscle tension?
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It decreases to zero.
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During a period of relaxation of a muscle twitch, what happens to contractile force and muscle tension?
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Contractile force declines and muscle tension decreases to zero.
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What term is best described by the following statement:
" Constant, slightly contracted state of all muscles " |
muscle tone
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What is muscle tone?
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Constant, slightly contracted state of all muscles
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What causes muscle tone?
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Due to spinal reflexes that activate groups of motor units alternately in response to input from stretch receptors in muscles
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_________ is due to spinal reflexes that activate groups of motor units alternately in response to input from stretch receptors in muscles
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muscle tone
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Muscle tone is due to __________ that activate groups of motor units alternately in response to input from stretch receptors in muscles.
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spinal reflexes
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Muscle tone is due to spinal reflexes that do what ?
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activate groups of motor units alternately in response to input from stretch receptors in muscles
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Muscle tone is due to spinal reflexes that activate groups of motor units alternately in response to input from ____________.
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stretch receptors in muscles
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What does skeletal muscle tone do?
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maintains posture and stabilizes joints
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______ keeps muscles firm, healthy, and ready to respond.
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Muscle tone
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During what phase of a muscle twitch does calcium re-enter the sarcoplasmic reticulum?
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period of relaxation
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During the period of relaxation phase of a muscle twitch, what does calcium do?
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re-enters the sarcoplasmic reticulum
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During the period of relaxation phase of a muscle twitch, what re-enters the sarcoplasmic reticulum?
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calcium
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During the period of relaxation phase of a muscle twitch, calcium re-enters what?
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the sarcoplasmic reticulum
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