7.3- whole skeletal muscle anatomy

Question 1

muscle fascicles (bundles of muscle fibers) are covered by this connective tissue layer called

Answer 1

the perimysium

Question 2

the entire muscle is surrounded by a connective tissue layer called the

Answer 2

epimysium

Question 3

Motor Neurons extend together with ____ and _____ thru the connective tissue and skeletal muscles

Answer 3

arteries and veins

Question 4

skeletal muscle is ____- % of body weight

Answer 4

40

Question 5

skeletal muscle is also called

Answer 5

striated muscle

Question 6

a skeletal muscle consists of what 4 tissues?

Answer 6

skeletal muscle tissue, nervous tissue, connective tissue, and adipose tissue

Question 7

each muscle cell is called a

Answer 7

muscle fiber

Question 8

the skeletal muscle has three layers of connective tissue

Answer 8

1. the epimysium
2. the perimysium
3. the endomysium

Question 9

What forms a connective tissue sheath AROUND each skeletal muscle, and is the OUTER LAYER of the muscle?

Answer 9

the epimysium

Question 10

bundles of muscle fibers (cells)

Answer 10

fascicles

Question 11

what subdivides each whole muscle into fascicles, and serves as passageways for blood vessels and nerves to supply each fascicle ?

Answer 11

the perimysium

Question 12

A delicate layer of connective tissue, separates individual muscle fibers WITHIN each fascicle, and serves as a passageway for nerve fivers an blood vessels that supply each separate muscle fiber.

Answer 12

The endomysium

Question 13

Fibrous connective tissue layer surrounding a skeletal muscle

Answer 13

.epimysium

Question 14

Fibrous sheath enveloping each of the skeletal muscle fascicles

Answer 14

perimysium

Question 15

Fine connective tissue sheath surrounding a muscle fiber.

Answer 15

endomysium

Question 16

the protein fibers of the three layers of connective tissue blend into one another and merges at the ends of most muscles forming

Answer 16

tendons

Question 17

tendons

Answer 17

connect muscles to bones

Question 18

the three muscle fiber components that respond to and transmit electrical signals

Answer 18

1. the sarcolemma
2. the transverse tubules
3. the sarcoplasmic reticulum

Question 19

the cell membrane of muscle fibers, surrounds fiber
outer to inner
endomysium, sarcolemma, sarcoplasm

Answer 19

sarcolemma

Question 20

tubelike inward folds of the sarcolemma, carries electrical impulses into the center of the muscle fiber so the fiber contracts as a whole

Answer 20

transfers tubules ( T tubules) tubes

Question 21

endoplasmic reticulum in skeletal muscle fivers that stores high levels of Ca 2+

Answer 21

sarcoplasmic reticulum- small yellow

Question 22

release of _____ from the sarcoplasmic reticule is a switch for muscle contraction

Answer 22

Ca 2+

Question 23

cytoplasm in muscle fibers

Answer 23

sarcoplasm - pink and liquid

Question 24

enlarged portions of the sarcoplasmic reticulum

Answer 24

terminal cisternae - big yellow

Question 25

two terminal cisternae and their associate T Tubule form a

Answer 25

triad (t tubule sandwich)

Question 26

two main structures of contractibility in muscle fibers

Answer 26

myofibrils and myofilaments

Question 27

BUNDLES of protein filaments ( actin and myosin)

Answer 27

myofibrils

Question 28

Ultramicroscopic protein thread helping form myofibrils in skeletal muscle

Answer 28

myofilaments

Question 29

two types of myofilaments

Answer 29

actin and myosin

Question 30

thin myofilaments

Answer 30

actin

Question 31

thick myofilaments, golf club

Answer 31

myosin

Question 32

actin and myosin filaments are arranged into these highly ordered units.

Answer 32

sarcomeres

Question 33

Sarcomeres join end to end, forming the _______

Answer 33

myofibrils

Question 34

form a stationary anchor for actin myofilaments

Answer 34

Z disks

Question 35

One _______ extends from one Z disk to the next Z disk

Answer 35

sarcomere

Question 36

the regions of each sarcomere

Answer 36

i band (2 regions) and an A band

Question 37

two lighter- stained regions

Answer 37

I bands

Question 38

central darker-stained regions, center of each sarcomere. contains both actin and myosin filament overlapping (except in the center)

Answer 38

A band

Question 39

the center of each A band has a smaller band called the __ _____. contains only myosin myofilaments.

Answer 39

H zone

Question 40

the middle of each H zone has this dark line. it consists of delicate protein filaments that hold the myosin myofilaments in place

Answer 40

M line

Question 41

three separate proteins of each actin myofilament

Answer 41

1. actin 2. tropomyosin 3. troponin

Question 42

______ act as receptor sites for a portion of the myosin myofilament, the myosin head.

Answer 42

Actin

Question 43

long, fibrous protein that lies in the groove along the fibrous actin strand

Answer 43

tropomyosin

Question 44

in a relaxed muscle, _________ is covering the attachment sites on the actin. A muscle cannot contract until it moves to uncover the active sites.

Answer 44

tropomyosin

Question 45

has a 1. subunit that anchors the troponin to the actin, 2. a subunit that prevents the tropomyosin from uncovering the actin attachment sites, 3. and a subunit that binds Ca 2+

Answer 45

troponin

Question 46

Myosin myosin filaments are composed of many elongated _______ molecules shaped like golf clubs

Answer 46

myosin

Question 47

each myosin molecule consist of a _____ portion and ______ myosin heads.

Answer 47

rod, heads

Question 48

What do myosin heads do?

Answer 48

bind to active sites on the actin to form cross-bridges to contract muscle, are attached to the rod portion that bends and straightens during contraction, and break down ATP, releasing energy

Question 49

motor neurons carry electrical signals called

Answer 49

action potentials

Question 50

The point of contact of motor neuron axon branches with the muscle fiber

Answer 50

synapse (neuromuscular junction)

Question 51

A Synapse (neuromuscular junction) consist of what two things?

Answer 51

1. axon terminals and 2. the area of the muscle fiber sarcolemma they innervate

Question 52

each axon terminal is called the

Answer 52

presynaptic terminal

Question 53

the space between the presynaptic terminal and the muscle fiber is the

Answer 53

synaptic cleft

Question 54

the muscle cell membrane in the area of the junction is called the

Answer 54

motor end plate (postsynaptic membrane)

Question 55

each presynaptic terminal contains numerous mitochondria and SMALL SPHERICAL SACS called

Answer 55

synaptic vesicles

Question 56

the synaptic vesicles contain the neurotransmitter

Answer 56

acetylcholine

Question 57

What is a molecule that allows a neuron to communicate with its target, and A chemical released at the distal end of an axon that either stimulates or inhibits an adjacent cell? they cans simulate or inhibit the production of an action potential in the motor end plate (the sarcolemma) by binding to ligand gated ion channels they are released from the presynaptic membrane and diffuse across the synaptic cleft to alter the activity of the muscle fiber.

Answer 57

neurotransmitter

Question 58

specialized membrane transport proteins that are opened and closed by specific molecules, such as neurotransmitters. when opened, they allow ions to cross the cell membrane

Answer 58

Ligand ( or ligand gated ion channels)

Question 59

Mechanism by which actin and myosin myofilaments slide over one another during muscle contraction.

Answer 59

sliding filament model

Question 60

what forms when the myosin binds to the actin?

Answer 60

a cross-bridge

Question 61

myofibrils appear ____ because of A bands and I bands

Answer 61

striated

Question 62

what happens during the muscle fiber contraction ?

Answer 62

actin and myosin filaments slide past one another, shortening the sarcomeres