Skeletal Muscle and Nerve Tissue Histology Flashcards Preview

MSK-1 > Skeletal Muscle and Nerve Tissue Histology > Flashcards

Flashcards in Skeletal Muscle and Nerve Tissue Histology Deck (54)
Loading flashcards...
1
Q

How many nerves innervate a muscle fiber?

A

1

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

2
Q

What type of muscle never fatigues?

A

cardiac

3
Q

What do smooth muscle cells look like?

A

NOT striated

uninucleated

4
Q

What do cardiac muscle cells look like?

A

striated
uninucleated
branched cells
separated by intercalated disks

5
Q

What is in a triad?

A

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

6
Q

What are a-motor nerve fibers?

A

efferent

receive signal from Ia fibers and cause extrafusal fibers to contract

7
Q

What is in the soma/body of a neuron

A

all the organelles

8
Q

What is the synapse?

A

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

9
Q

What is a muscle made of?

What is it surrounded by?

A

group of fascicles

surrounded by epimysium

10
Q

What is the I band

A

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

11
Q

what are type I muscle fibers?

A

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

12
Q

What is the A band

A

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

13
Q

What is a myofiber/muscle fiber made up of?

what surrounds a myofiber?

A

myofibrils = chains of sarcomeres

covered by endomysium

14
Q

What is the z-disk

A

separates sarcomeres; attachment site for actin and titin

15
Q

What is myosin made up of?

A

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

16
Q

What is a dendrite?

A

part of neuron that receives signals

17
Q

What is a sarcomere?

A

contractile unit of muscle made of actin and myosin

18
Q

What is the axon?

A

part of neuron that sends out signal to synapse

19
Q

what does tropomyosin do?

A

wraps between actin strands

troponin sits on top of tropomyosin

20
Q

What is the axon hillock?

A

connection btw soma and axon

summates electrical signals received by all dendrites

21
Q

What makes an entire muscle shorten during contraction?

A

All myofibrils contract at the same time

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

22
Q

What are bipolar neurons?

A
single dendrite (w/ multiple extensions)
one axon
23
Q

what are intrafusal muscle fibers?

A

fibers that sense length and rate of change of muscle

24
Q

What is a nerve?

What surrounds it?

A

group of fascicles

surrounded by epineurium

25
Q

What are type Ia sensory nerve fibers?

A

afferent

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

26
Q

What is an actin filament made of?

A

f-actin monomers

27
Q

What is the sarcoplasmic reticulum?

A

tubular system acting like smooth ER

28
Q

What type of muscle is not striated?

A

smooth muscle

29
Q

What is nebulin?

A

ruler for determining length of actin filament

30
Q

What are type IIB muscle fibers?

A
fast twitch, powerful contraction
few mitochondria
few myoglobin
rapidly fatigue
anaerobic respiration
31
Q

What are extrafusal muscle fibers?

A

regular skeletal M, contract muscle

32
Q

What is the M-line?

A

attachment site for myosin on sarcomere

33
Q

What are transverse T tubules

A

branches are sarcolemma penetrating muscle cells to convey electrical signal

34
Q

What is a schwann cell

A

myelinate axons in PNS

wrap around one part of ONE axon

35
Q

What is the H band?

A

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

36
Q

What are terminal cisternae?

A

flattened sac of SR on either side of transverse T tubule

37
Q

What are g-motor nerve fibers

A

efferent

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

38
Q

What covers an axon?

A

endoneurium

on top of myelin if axon is myelinated

39
Q

What are on the heavy chains of myosin?

A

globular heads w/ actin binding site and ATPase domains

40
Q

What is the sarclemma?

A

membrane around each muscle cell

41
Q

What are multipolar neurons?

A

multiple dendrites

one axon

42
Q

What is the nissle substance?

A

abundant rER w/in cytoplasm of the soma

43
Q

What are pseudounipolar neurons?

A

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

44
Q

What is a fascicle?

What is it covered by?

A

group of axons

covered by perineurium

45
Q

What causes troponin to move so myosin can bind actin?

A

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

46
Q

what type of motor neurons innervate skeletal muscle?

A

a-motor neurons from anterior horn of spinal cord

47
Q

What does troponin do?

A

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

48
Q

What type of muscle is multinucleated?

A

skeletal muscle

49
Q

What is a fasicle?

What is it surrounded by?

A

group of myofibers

covered by perimysium

50
Q

What do skeletal muscle cells look like?

A

striated
multinucleated
large cells

51
Q

What are end feet?

A

connect T tubules w/ SR to allow Ca release

52
Q

What are type IIA muscle fibers?

A
fast/intermediate, powerful
many mitochondria
many myoglobin
intermediate fatigability
aerobic, but less O2 than type I
53
Q

What is the sarcoplasm?

A

cytoplasm of muscle cell

54
Q

What is an oligodendrocyte?

A

myelinate axons in CNS

Wrap around a part of MANY axons