Skeletal Muscle and Nerve Tissue Histology

Question 1

How many nerves innervate a muscle fiber?

Answer 1

1

a single nerve can innervate more than one muscle, but only 1 nerve per muscle

Question 2

What type of muscle never fatigues?

Answer 2

cardiac

Question 3

What do smooth muscle cells look like?

Answer 3

NOT striated

uninucleated

Question 4

What do cardiac muscle cells look like?

Answer 4

striated
uninucleated
branched cells
separated by intercalated disks

Question 5

What is in a triad?

Answer 5

T tubule + 2 terminal cisternae (one on either side)

Question 6

What are a-motor nerve fibers?

Answer 6

efferent

receive signal from Ia fibers and cause extrafusal fibers to contract

Question 7

What is in the soma/body of a neuron

Answer 7

all the organelles

Question 8

What is the synapse?

Answer 8

space btw axon and tissue; transfers electrical impulse from neuron to target tissue

Question 9

What is a muscle made of?

What is it surrounded by?

Answer 9

group of fascicles

surrounded by epimysium

Question 10

What is the I band

Answer 10

space on either side of the Z disk where there is no myosin

Question 11

what are type I muscle fibers?

Answer 11

slow twitch, less powerful
many mitochondria = slow fatigability
aerobic respiration
abundant myoglobin

Question 12

What is the A band

Answer 12

distance from end of one myosin head to the head of opposite myosin = overlap of actin and myosin
H band is within a band

Question 13

What is a myofiber/muscle fiber made up of?

what surrounds a myofiber?

Answer 13

myofibrils = chains of sarcomeres

covered by endomysium

Question 14

What is the z-disk

Answer 14

separates sarcomeres; attachment site for actin and titin

Question 15

What is myosin made up of?

Answer 15

2 heavy chains
2 light chains
Held in place on z-disk by Titin

Question 16

What is a dendrite?

Answer 16

part of neuron that receives signals

Question 17

What is a sarcomere?

Answer 17

contractile unit of muscle made of actin and myosin

Question 18

What is the axon?

Answer 18

part of neuron that sends out signal to synapse

Question 19

what does tropomyosin do?

Answer 19

wraps between actin strands

troponin sits on top of tropomyosin

Question 20

What is the axon hillock?

Answer 20

connection btw soma and axon

summates electrical signals received by all dendrites

Question 21

What makes an entire muscle shorten during contraction?

Answer 21

All myofibrils contract at the same time

actin and myosin DO NOT change in length - overlap each other

Question 22

What are bipolar neurons?

Answer 22

single dendrite (w/ multiple extensions)
one axon

Question 23

what are intrafusal muscle fibers?

Answer 23

fibers that sense length and rate of change of muscle

Question 24

What is a nerve?

What surrounds it?

Answer 24

group of fascicles

surrounded by epineurium

Question 25

What are type Ia sensory nerve fibers?

Answer 25

afferent | innervate intrafusal fibers to sense change in length and send signal back to spinal cord of overstretching

Question 26

What is an actin filament made of?

Answer 26

f-actin monomers

Question 27

What is the sarcoplasmic reticulum?

Answer 27

tubular system acting like smooth ER

Question 28

What type of muscle is not striated?

Answer 28

smooth muscle

Question 29

What is nebulin?

Answer 29

ruler for determining length of actin filament

Question 30

What are type IIB muscle fibers?

Answer 30

``` fast twitch, powerful contraction few mitochondria few myoglobin rapidly fatigue anaerobic respiration ```

Question 31

What are extrafusal muscle fibers?

Answer 31

regular skeletal M, contract muscle

Question 32

What is the M-line?

Answer 32

attachment site for myosin on sarcomere

Question 33

What are transverse T tubules

Answer 33

branches are sarcolemma penetrating muscle cells to convey electrical signal

Question 34

What is a schwann cell

Answer 34

myelinate axons in PNS | wrap around one part of ONE axon

Question 35

What is the H band?

Answer 35

space on either side of M line where there is no actin, but there is myosin shortens during contraction

Question 36

What are terminal cisternae?

Answer 36

flattened sac of SR on either side of transverse T tubule

Question 37

What are g-motor nerve fibers

Answer 37

efferent | receive signal from type Ia fibers and cause intrafusal muscle fibers to contract

Question 38

What covers an axon?

Answer 38

endoneurium | on top of myelin if axon is myelinated

Question 39

What are on the heavy chains of myosin?

Answer 39

globular heads w/ actin binding site and ATPase domains

Question 40

What is the sarclemma?

Answer 40

membrane around each muscle cell

Question 41

What are multipolar neurons?

Answer 41

multiple dendrites | one axon

Question 42

What is the nissle substance?

Answer 42

abundant rER w/in cytoplasm of the soma

Question 43

What are pseudounipolar neurons?

Answer 43

one cell process w/ single axon branch and single dendrite branch arise from neural crest = sensory

Question 44

What is a fascicle? | What is it covered by?

Answer 44

group of axons | covered by perineurium

Question 45

What causes troponin to move so myosin can bind actin?

Answer 45

calcium released from SR --> binds troponin --> conformational change --> actin binding sites accessible to myosin

Question 46

what type of motor neurons innervate skeletal muscle?

Answer 46

a-motor neurons from anterior horn of spinal cord

Question 47

What does troponin do?

Answer 47

sits on tropomyosin strands and covers myosin binding sites on actin filament

Question 48

What type of muscle is multinucleated?

Answer 48

skeletal muscle

Question 49

What is a fasicle? | What is it surrounded by?

Answer 49

group of myofibers | covered by perimysium

Question 50

What do skeletal muscle cells look like?

Answer 50

striated multinucleated large cells

Question 51

What are end feet?

Answer 51

connect T tubules w/ SR to allow Ca release

Question 52

What are type IIA muscle fibers?

Answer 52

``` fast/intermediate, powerful many mitochondria many myoglobin intermediate fatigability aerobic, but less O2 than type I ```

Question 53

What is the sarcoplasm?

Answer 53

cytoplasm of muscle cell

Question 54

What is an oligodendrocyte?

Answer 54

myelinate axons in CNS | Wrap around a part of MANY axons