Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

histology > unit 4 > Flashcards

unit 4 Flashcards

1
Q

what are the four properties of muscle?

A

excitability, contractility, extensibility, elasticity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does a skeletal muscle consist of?

A

contractile tissue composed of muscle cells
a series of collagen-based connective tissue coverigs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what do the connective tissue coverings do?

A

bind muscle fibers, link skeletal muscle to bone, transduce force to attached structures, convey neurovasculature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how are skeletal muscle cells developed?

A

myoblasts fuse to form a single skeletal muscle cell
once fusion occurs, muscle fibers cannot divide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how do muscles enlarge?

A

by hypertrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are satellite cells?

A

myoblasts that remain in muscle
stem cell like cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how does muscle fiber regeneration occur?

A

satellite cells divide and fuse to form new muscle fibers
they are activated when needed for healing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

features of skeletal muscle

A

long cylindrical cells, multinucleate, appears striated due to overlapping thick and thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
A

longitudinal skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
A

cross section skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

endomysium

A

layer of reticular fibers that surrounds individual muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

perimysium

A

CT layer that surrounds a group of fibers to form a fascicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

epimysium

A

dense CT that surrounds a collection of fascicles
deep fascia that surrounds muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is a fascicle

A

multiple muscle fibers grouped
functional unit of muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
A

denervation atrophy of skeletal muscle due to motor neuron damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the myotendinous junction?

A

site of attachment of a muscle fiber and the contiguous CT of the tendon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the purpose of a myotendinous junction?

A

increase SA of contact and enhance adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what surrounds each muscle fiber?

A

capillary beds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where are the parts of a nerve that go to skeletal muscle?

A

cell body - SC or brain
axon - in neurovascular bundle to muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

fine movement

A

a few branches innervate a small number of muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

gross movement

A

many branches innervate thousands of muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

red fibers

A

type I, slow
slow contraction speed, fatigue resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

intermediate fibers

A

type IIa, fast oxidative-glycolytic
fast contraction speed, relatively fatigue resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

white fibers

A

type IIb, fast glycolytic, fast twitch
fastest contraction speed, fatigue quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

structure of myofibrils

A

long bundles of myofilaments that extend the entire length of the fiber and occupy most of the sarcoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

A band

A

contain thick filaments and overlapping thin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

I band

A

remaining thin filament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Z line

A

protein dense regions separating sarcomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

H zone

A

portion of A band containing only thick filaments and no myosin heads

30
Q

M line

A

protein dense region in the middle of the H zone

31
Q
A
32
Q

how are adjacent sarcomeres structured?

A

they are aligned

33
Q

what is myosin?

A

a molecular motor protein that is a major component of thick filaments

34
Q

what are myosin composed of?

A

2 heavy chains and 4 light chains

35
Q

structure of myosin

A

tails associate in antiparallel fashion with a central bare zone and myosin heads that radiate around ends

36
Q

what does a myosin head contain?

A

actin binding site and ATP binding site

37
Q

what is actin?

A

a major component of thin filaments that contains a binding site for myosin head

38
Q

what does tropomyosin do?

A

covers myosin binding sites on actin

39
Q

what does troponin T, I, and C do?

A

T - binds to tropomyosin
I - binds to actin
C - binds to calcium

40
Q

what does the binding of TnC and Ca do?

A

causes conformational change where tropomysoin moves to make the binding site on actin accessible

41
Q

which filament slides during muscle contraction?

A

thin filaments slide over thick filaments toward M line

42
Q

what zones/bands change during muscle contraction?

A

Z discs, I bands, H zone

43
Q

what is the sarcoplasmic reticulum?

A

a special type of sER that is composed of membranous sacs and anastomosing channels encircling each myofibril

44
Q

terminal cisternae

A

dilated sacs at ends of each sarcoplasmic reticulum networks

45
Q

what is the function of the sarcoplasmic reticulum?

A

stores high concentrations of stored Ca2+ in terminal cisternae

46
Q

where are mitochondria and glycogen deposits located?

A

adjacent to sarcoplasmic reticulum

47
Q

what are transverse tubules (T-tubules)

A

invaginations of sarcolemma into the cell

48
Q

what do T-tubules form?

A

a network of channels lined by specialized plasma membrane that wrap around each myofibril

49
Q

triad

A

t-tubules associate with terminal cisternae of two sarcomeres

50
Q

neuromuscular junction structure

A

axon forms a dilation called axon terminus that houses synaptic vesicles
axon termini lie in a depression of the sarcolemma

51
Q

function of neuromuscular junction

A

initiate events that lead to skeletal muscle contraction:
Ach released and binds to AchR on sarcolemma, leads to influx of Na+, depolarizes membrane, action potential is reached

52
Q

once an action potential is reached at the NMJ, what happens?

A

Ca2+ released from SR into sarcoplasm cause troponin to move tropomyosin, the contraction cycle begins

53
Q

contraction cycle

A
54
Q
A

longitudinal cardiac muscle

55
Q
A

cross section cardiac muscle

56
Q

three types of cell junctions in intercalated discs

A

fascia adherens, desmosomes, gap junctions

57
Q

fascia adherens

A

hold cells together, link to actin in nearest sarcomere
similar to adherens junctions

58
Q

desmosomes

A

hold cells together, link to IF network
similar to maculae adherens

59
Q

gap junctions

A

spread action potential , allow for coordinated contraction

60
Q

how is contraction of cardiac muscle initiated?

A

by cardiac conducting cells (modified cardiomyocytes)

61
Q

cardiac muscle contraction

A

membrane is depolarized which extends to T-tubules
signals SR, releases Ca2+
Ca2+ binds to TnC…

62
Q

how does the depolarization signal travel in cardiac cells?

A

from one cell to the next via gap junctions, slower than skeletal muscle

63
Q
A

cross section smooth muscle

64
Q
A

longitudinal smooth muscle

65
Q

unique features of smooth muscle

A

no T-tubules
non-striated
stretchier and greater contractile time
can contract in wave pattern or along the entire length
robust cell proliferation

66
Q

visceral smooth muscle

A

in walls of vasculature and hollow organs
connected via gap junctions for rapid spread of action potential

67
Q

multiunit smooth muscle

A

few gap junctions, each cell acts independently

68
Q

myofilaments in smooth muscle

A

organized into bundles that are oriented in all directions

69
Q

initiation of smooth muscle contraction

A

electrical, mechanical, chemical

70
Q

smooth muscle contraction

A

thin filaments slide past thick which generates tension transmitted to IFs, IFs pull on sarcolemma
shortening occurs in all directions

histology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions