OS 203 2.2 Muscle Tissue - Sheet1

Question 1

A band - “A,” means?

Answer 1

anisotropic - birefringent in polarized light

Question 2

what’s in the A band

Answer 2

thick and thin filaments except at H band (thick only)

Question 3

I band - “I,” meaning?

Answer 3

isotropic - does not alter polarized light

Question 4

bisects the I band, name means?

Answer 4

Z line, Zwischesheibe - between discs

Question 5

light area bisecting the A band, name means? contains what?

Answer 5

H band, Heller (light), thick filament only

Question 6

bisects H band, proteins? (3)

Answer 6

M line; myomesin, a-actinin, titin

Question 7

attaches thick filaments at the center of the M line

Answer 7

myomesin

Question 8

attaches thin filaments to the Z line

Answer 8

a-actinin

Question 9

extends from M line to Z line; maintains central location of A band; prevents over-stretching. appearance?

Answer 9

titin; coiled appearance at the attached portion in the I band

Question 10

inner surface of sarcolemma is coated with what? function?

Answer 10

dystrophin - protects muscle from stress during contraction

Question 11

x-linked autosomal recessive mutation affecting the expression of dystrophin (unable to walk by puberty)

Answer 11

duchenne muscular dystrophy

Question 12

sarcoplasm contains

Answer 12

glycogen (for anaerobic glycolysis) and myoglobin

Question 13

continuation of SR with gated calcium release channels; reservoir of?

Answer 13

terminal cisternae; calcium ions and calsequestrin

Question 14

continuation of sarcolemma; location in skeletal muscle; fxn

Answer 14

T tubule; A-I jxn; interiorization of action potential

Question 15

myosin components

Answer 15

2 chains heavy meromyosin (HMM) with heads at A band, ATP-binding site; light meromyosin (LMM) with tail at H band

Question 16

thin filament components (3)

Answer 16

F-actin, troponin, tropomyosin

Question 17

F-actin is made of

Answer 17

2 strands G-actin (with myosin binding sites) wound around e/o

Question 18

troponin portions (3)

Answer 18

TnC (binds Ca), TnI (inhibit actin-myosin, binds to actin), TnT (binds to tropomyosin)

Question 19

remove this to expose the binding site

Answer 19

troponin-tropomyosin complex

Question 20

remains unchanged during contraction

Answer 20

A band

Question 21

motor neuron and all muscle fibers it innervates

Answer 21

motor unit / neuromotor unit

Question 22

branches in the terminal ends of nerve axon attached to the myofiber

Answer 22

terminal bouton

Question 23

large motor unit: how many innervated? examples?

Answer 23

~100 muscle fibers; back, biceps

Question 24

small motor unit: how many innervated? examples?

Answer 24

~3-5 muscle fibers; eye, hand

Question 25

motor end plate / myoneural jxn: neurotransmitter

Answer 25

acetylcholine

Question 26

primary vs secondary synaptic cleft

Answer 26

primary: between axon and sarcolemma; secondary (subneural cleft?): deep folds in the sarcolemma

Question 27

postsynaptic membrane contains

Answer 27

nicotinic acetylcholine receptors (ligand-gated Na+ channels)

Question 28

disorder: antibodies developed against receptors for acetylcholine -> weakness and fatigue in eyes, fingers, respiratory muscles

Answer 28

myasthenia gravis

Question 29

red muscle //

Answer 29

red / type 1 / slow twitch oxidative

Question 30

white muscle //

Answer 30

white / type 2b / fast twitch glycolytic

Question 31

intermediate muscle //

Answer 31

intermediate / type 2a / fast twitch oxidative

Question 32

red vs white vs intermediate: fiber diameter

Answer 32

red small, white large, intermediate intermediate :))

Question 33

red vs white vs intermediate: color

Answer 33

red red, white white, intermediate pink hahahahaha

Question 34

red vs white vs intermediate: mitochondria

Answer 34

red many, white few, intermediate many (*oxidation!!)

Question 35

red vs white vs intermediate: myoglobin, capillary density

Answer 35

red rich, white few, intermediate intermediate :))

Question 36

red vs white vs intermediate: fatigue rate

Answer 36

red slow, white fast, intermediate intermediate

Question 37

red vs white vs intermediate: twitch rate

Answer 37

red slow, white fast, intermediate fast

Question 38

red vs white vs intermediate: glycogen content

Answer 38

red low, white abundant, intermediate intermediate

Question 39

red vs white vs intermediate: histochemical reaction

Answer 39

red - high NADH, succinate dehydrogenase; white - low both; intermediate - medium to high

Question 40

red vs white vs intermediate: fxn

Answer 40

red - steady power, endurance (marathon); white - explosive bursts (weight lifting, short sprint); intermediate - combination (long sprint)

Question 41

intensity of contraction is based on (3)

Answer 41

number of motor units innervated, kind of motor units stimulated, firing frequency of activated units

Question 42

repairs muscle fibers; location? appearance? only seen in? repair can be done only if?

Answer 42

bet plasmalemma & lamina; large nucleus scarce cytoplasm; in skeletal muscle only; only if basal lamina is intact!

Question 43

single celled embryologic cells that fused -> multinucleated skeletal muscle

Answer 43

myoblasts (syncytium)

Question 44

smooth: vesicular invaginations of plasmalemma; fxn (analogous to)

Answer 44

caveolae; aids in calcium uptake and release (analogous to T tubule system)

Question 45

smooth: where thin & intermediate filaments converge and attach directly/indirectly to sarcolemma; analogous to? contains what?

Answer 45

dense bodies; analogous to z line; contains alpha actinin

Question 46

contraction of smooth: release of (?) -> binds with (?) -> phosphorylates (?) -> reacts with (?)

Answer 46

Ca-calmodulin complex; myosin light chain kinase (MLCK) enzyme; phosphorylates light chain (myosin); reacts with actin

Question 47

unique about the contraction of smooth muscle

Answer 47

light chain (myosin) must be phosphorylated before it can react with actin

Question 48

unitary innervation: how does impulse travel? fibers contract as a unit called? location?

Answer 48

gap jxn; syncytial smooth muscle; visceral muscles & bv

Question 49

multiunit innervation: one nerve cell innervates many muscle fibers which can contract individually location? (3)

Answer 49

ciliary body (eyes), wall of large bv, male reproductive tract

Question 50

pigment observable in cardiac muscle

Answer 50

lipochrome? lipofuscin from residual bodies

Question 51

xs: skeletal vs cardiac

Answer 51

skeletal - polygonal outlines; cardiac - continuum of myofibrils interspersed with sarcosome

Question 52

skeletal vs cardiac: t tubule, sarcoplasmic reticulum

Answer 52

cardiac - wider t tubule but less numerous & less developed SR

Question 53

skeletal is to triad as cardiac is to what? components? location?

Answer 53

dyad = t tubule + flattened saccule (no terminal cisternae); found in Z line

Question 54

intercalated disc configuration; coincides w/?

Answer 54

stairway; Z line

Question 55

intercalated disc: 3 types of jxn

Answer 55

fascia adherens, macula adherens (desmosome), gap junction

Question 56

intercalated disc: fascia adherens fxn

Answer 56

anchoring sites for actin filaments

Question 57

intercalated disc: desmosomes fxn

Answer 57

binds cardiac cells together (prevents tearing apart when heart contracts)

Question 58

intercalated disc: gap jxn fxn

Answer 58

ionic continuity

Question 59

atrial vs ventricular muscle fibers: t tubules, granules

Answer 59

atrial - smaller & fewer T tubule; atrial natriuretic peptide (ANP) in secretory granules

Question 60

ANP released in response to? fxn? opposite to?

Answer 60

in response to high blood volume; reduce blood pressure by vasodilation & Na+ & H2O loss; opposite to aldosterone

Question 61

2 types proprioreceptors

Answer 61

muscle spindle, golgi tendon

Question 62

muscle spindle location

Answer 62

perimysium

Question 63

muscle spindle structure

Answer 63

intrafusal (modified striated) fibers within CT capsule witihin extrafusal fibers

Question 64

what exactly does the muscle spindle detect? what is it responsible for?

Answer 64

change in length of extrafusal fibers; for regulation of muscle tone via spinal stretch/myotactic reflex (patellar reflex)

Question 65

intrafusal vs extrafusal fibers

Answer 65

intrafusal - very few myofibrils

Question 66

nuclear chain fibers vs nuclear bag fibers

Answer 66

nuclei closely aligned; piled in central dilation

Question 67

golgi tendon location

Answer 67

junction of muscle and tendon

Question 68

golgi tendon structure

Answer 68

small bundle of encapsulated collagen fibers

Question 69

golgi tendon: what exactly does it detect?

Answer 69

changes in muscle tension or force of muscle contraction