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Anatomy I Unit 1 > L7-L8 Muscle Tissue I and II > Flashcards

L7-L8 Muscle Tissue I and II Flashcards

1
Q

What are 3 types of muscle?

A
  1. Skeletal
  2. Cardiac
  3. Smooth
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2
Q

What is a muscle fiber? (=)

A

Muscle fiber = muscle cell = myocyte

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3
Q

All muscle fibers are _______? * and what happens?

A

Contractile, **Muscles contract by getting shorter

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4
Q

Function of muscle fibers?

A

Produce force, movement, and heat

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5
Q

Where are muscle fibers located?

A

Surrounded by connective tissue matrix and are bounded by external lamina

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6
Q

3 Unique terminology of muscle fibers? And what are they really in other parts (other names)?

A
  1. Sarcolemma: plasma membrane
  2. Sarcoplasm: cytoplasm
  3. Sarcoplasmic reticulum (SR)
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7
Q

What is a contraction?

A

Interaction of cytoplasmic protein chains = myofilaments

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8
Q

What are the thin and thick filaments?

A

Actin (thin) & Myosin (thick)

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9
Q

____ causes conformational change of muscle fibers?

A

Ca 2+

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10
Q

Striated vs Nonstriated muscle?

A

Striated: skeletal and cardiac muscle stripes
Nonstriated: smooth muscle

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11
Q

What is cell diameter proportional to?

A

Force production - rich blood supply in surrounding CT

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12
Q

Skeletal muscle has abundance of? (3)

A
  1. Mitochondria
  2. Glycogen (mainly store carbs for energy)
  3. Myoglobin (similar to hemoglobin but with more oxygen)
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13
Q

Organization of skeletal muscle?

A

Tendon -> muscle -> fascicle -> muscle fiber -> myofibrils

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14
Q

Definition of fascicle?

A

Bundles of muscle fibers

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15
Q

Muscle fibers definition?

A

Myocyte (muscle cell)

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16
Q

Myofibrils definition?

A

Long rows of myofilaments, more than 1 nucleus

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17
Q

What is skeletal muscle invested by?

A

Connective tissue

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18
Q

What is endomysium and where is it located?

A

Endomysium is AROUND cells; type IV, III collage (similar to basal lamina/ reticular lamina function).. stuck to muscle sarcolemma

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19
Q

What is perimysium and where is it located?

A

Around fascicles; type I collagen; surrounded by epimysium

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20
Q

What is epimysium and where is it located?

A

Around the whole muscle, type I collagen, smallest unit made up of muscle fiber; surrounded by endomysium

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21
Q

What are two types of skeletal muscle?

A

Red muscle, white muscle

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22
Q

Red muscle features?

A

Slow-twitch, type I

  • Aerobic
  • Abundant mitochondria & myoglobin molecules
  • Slower, weaker, more fatigue resistance *
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23
Q

White muscle features?

A

Fast-twitch type II

  • Better capability for anaerobic glycolysis
  • More glycogen
  • Faster, stronger, less fatigue resistance*
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24
Q

What type of fibers share categories of both?

A

Intermediate fibers

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25
Q

What are the skeletal muscle striations at LM? (3)

A
  1. A bands: dArk band
  2. I bands: LIght bands
  3. Z disk: dark line in I band (also Z line looks like zipper)
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26
Q

When muscle contracts, what is it called and how is it accomplished?

A

Z disks come together and is called sarcomere, which is smallest contractile unit

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27
Q

What do striations result from?

A

Overlapping myofilament arrangement

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28
Q

Within the A band, what things are there? (2_

A

H band in the middle horizontally, M line in the dark line of the A band vertically

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29
Q

What is the sliding filament theory?

A

Z lines are brought closer together as myofilaments slide past each other (myofilaments do not change length)

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30
Q

What does the sarcoplasmic reticulum look like and what is a part of it?

A

Looks like tape with horizontal holepunch in cartoon figure; the terminal cisternae is part of SR that gets puffy

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31
Q

What is a terminal cisternae?

A

Invaginations of the sarcolemma

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32
Q

T-tubule, terminal cisternae on one side, and terminal cisternae on the other side are all called what?

A

Triad

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33
Q

What is the Triad? ***

A

2 terminal cisternae + 1 T-tubule are located at junction of A & I bands

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34
Q

In skeletal muscle, what is a motor unit?

A

Motor neuron + muscle fibers it innervates

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35
Q

What type of contraction principle does a motor unit follow?

A

“All or none”principle of contraction

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36
Q

At the end of the muscle fibers there are these rounds things- what are they called?

A

Terminal button

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37
Q

In the axon terminal of motor neuron, there are __?

A

Synaptic vesicles w/ ACh

38
Q

There is a space between terminal button and muscle fiber.. the synaptic vessels join with neuron’s plasma membrane and release ______ (steps)?

A

Neurotransmitter to synaptic cleft -> Sarcolemma of myocyte (junctional fold), usually ACh –> rush to T-tubule -> SR tells Z line to contract

39
Q

What would synaptic vesicles do?

A

Synaptic vesicles goes to the plasma membrane

40
Q

What is the common error students believe about the synaptic vesicles? (explain)

A

COMMON ERROR: students think SV cross synaptic cleft to go through muscle.. WHY wrong? bc plasma membrane is part of another cell. Instead, join (exocytosis or secretion of neurotransmitters) into synp cleft where it would be taken off by junctional folds

41
Q

What is the function of muscle spindles and Golgi tendon organ?

A

Monitor changes in length & tension and also participate in stretch reflex

42
Q

Nervous system divided into 2 directions of information?*

A
  1. Motor: info from CNS OUT*

2. Sensory: info from periphery IN*

43
Q

2 responses to stress in skeletal muscle?

A
  1. Limited hyperplasia (adding cells)

2. Primary response is hypertrophy

44
Q

Features of limited hyperplasia? (2)

A
  • No mitosis
  • Satellite cells may give rise to myoblasts (make muscle cells) if external lamina is intact - otherwise, scar tissue is formed
45
Q

Features of primary response of stress? (2)

A

Hypertrophy

  • Myocytes enlarge by addition of proteins
  • Satellite cells fuse with muscle fibers
46
Q

Clinical correlation- rigor mortis and how it works?*

A

Occurs following death because lack of ATP which prevents the disassociation of actin and myosin (stiffness b/c no energy to unlink them.. until it degrades and becomes relaxed again)
NO MEANS OF RETAINING CALCIUM*

47
Q

What are muscle tissue?

A

Major cells in body which contract and produce movement

48
Q

What is the difference between muscle and cardiac?

A

Cardiac muscle has ONE nucleus

49
Q

Where is the cardiac muscle located?

A

In myocardium of the heart & proximal portion of pulmory vv

50
Q

Cardiac muscle features? ___ ___

A

Striated, sarcomeres

51
Q

What are autorhythmic contractions and what do they do?

A
  • Modulated by autonomic neurons

- Propagated by gap junctions

52
Q

What are striated muscles under control of?

A

Somatic nervous system

53
Q

What are autonomic neurons?

A

Part of nervous system where we do not have conscious control over

54
Q

What do cardiac muscles have a tendency to do?

A

Branch and end in squiggly lines- like puzzle

55
Q

What are intercalated disks?

A

Dark-staining line where intercellular junctions occur

56
Q

In a EM of intercalated disks, what are the two important portions you need to know (and 2 anatomy parts of each)?

A
  • Transverse portion: Fascia adherens (FA), Desmosomes (D)

- Longitudinal portion: Gap junctions (N), less mechanical stress

57
Q

What is an important not about intercalated disks?

A

Abundant mitochondria & glycogen inclusions

58
Q

What keeps the intercalated disks together?

A

Nexus

59
Q

What are some features of cardiac muscle FIBERS? (4)

A
  • Can be branched, arranged in layers (laminae)
  • Mononucleated, central nucleus
  • Mitochondria and myoglobin in very high quantity
  • Intercalated discs with gap junctions
60
Q

What are connexons part of ____ _____ ?

A

Gap junction

61
Q

4 features cardiac muscle fibers?

A
  • T-tubules large, SR sparse, primarily extracellular
  • Calcium source
  • Diad at the Z disc
  • Sarcomeres and myofibrils
62
Q

What are Purkinje fibers?

A

They are specialized cardiac cells that can depolarize rapidly

63
Q

What occurs when cardiac muscles respond to stress? (3)

A
  • Hyperplasia is negligible (very limited cardiomyocyte mitosis)
  • Hypertrophy in response to mechanical stress (addition of proteins, but no satellite cells)
  • Injury typically leads to cell death & fibrosis (scar tissue)
64
Q

What is hyperplasia?

A

Increased cell prod in a normal tissue or organ

65
Q

What is hypertrophy?

A

In response to mechanical stress (addition of proteins, but no satellite cells)

66
Q

What are satellite cells?

A

Cells that aid in production of new skeletal muscle cells

67
Q

What is fibrosis (scar tissue)?

A

Created by surrounding connective tissue

68
Q

Of three types of muscle, which muscles look most disorganized?

A

Smooth muscle

69
Q

Where is smooth muscle found?

A
  • Found in hollow organs, blood vessels, dermis, respiratory passages
70
Q

Where are smooth muscles most often found in?

A

Perpendicular layers

71
Q

What do smooth muscles produce?

A

Their own “CT”matrix

72
Q

What are 3 characteristics of smooth muscle?

A
  1. Fusiform shape
  2. Single, central nucleus
  3. Not striated
73
Q

What are sarcomeres?

A

When 2 Z-disks come together

74
Q

Smooth muscles have NO ___?

A

T-tubules

75
Q

Sarcoplasmic reticulum is very sparse- what is the source and what is important about it?

A

Ca2+ source is mainly extracellular

76
Q

What are caveolae and what do they do?

A

Membrane invaginations that facilitate intake of Ca2+/ bring Ca from the ECM (slowest contractions .. milliseconds)

77
Q

What are smooth muscles and what do they do?

A

Crisscross patterns of myofilaments that facilitate contraction of fusiform shape

78
Q

What is anchored at the dense bodies?

A

Actin

79
Q

Actin has (2) features?

A
  • Similar function as Z lines

- Stabilized by intermediate filaments

80
Q

Myofilament have a ____ shape? What is exclusive about them?

A

Hook shape, they still need to contract but changes position and NOT size

81
Q

What is a focal adhesion?

A

Telling cells to stick together (spot wells but instead of associated with intermediate filament, it is associated with actin)

82
Q

Why are there rough ER proteins on smooth muscle and not the cardiac/ striated?**

A

Because makes OWN connective tissue

83
Q

Smooth muscle- what happens when the cell is relaxed versus contracted?***

A

When the cell is relaxed, the nucleus is oval-shaped

When the dense bodies physically move closer, it is corkscrew shape!

84
Q

What is a multiunit contraction? (3)

A
  • Muscle functions as multiple units of cells
  • Each unit innervated by a single ANS neruon
  • No/few gap junctions
85
Q

What are examples of the multiunit contraction?

A

Iris, vas deferens

86
Q

WHERE ARE TWO PLACES WHERE WE FIND MOST SMOOTH MUSCLE? **

A

blood vessels and gut

87
Q

What is significant about the axon terminals in CT?

A

No direct junction with muscle cells

88
Q

What is single-unit (unitary) contraction?

A

All cells contract together as a single unit b/c cells linked by gap junctions

89
Q

What are the single-unit contractions initiated by?

A

Mechanical/ chemical stimuli and modulated by ANS

90
Q

How are the contractions efficient?

A

Slow, energy efficient

91
Q

What are examples of single-unit contractions?

A

Uterus, GI & Urinary tracts

Anatomy I Unit 1 (8 decks)

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