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A&P I Lecture > exam 4 > Flashcards

exam 4 Flashcards

1
Q

What are the 3 types of muscles?

A

smooth, cardiac, & skeletal

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2
Q

What is smooth muscle?

A

found in the walls of hollow organs; made of spindle-shaped cells with 1 nucleus per cell

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3
Q

What is cardiac muscle?

A

found in the walls of the heart; made of branched, interwoven cells with 1 nucleus per cell

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4
Q

What are intercalated disks?

A

a special type of gap junction that joins cardiac muscle cells together & coordinate contraction

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5
Q

What is skeletal muscle?

A

for body movement; cylinder-shaped & can be very long; multinucleate cells with the nuclei located barely deep to the sarcolemma

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6
Q

What can all muscle types do?

A

contract, relax, & extend

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7
Q

Each skeletal muscle cell is covered in connective tissue called what?

A

endomysium

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8
Q

Groups of skeletal muscle cells (fascicles) are bound together by connective tissue called what?

A

perimysium

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9
Q

Bundles of fascicles are wrapped by connective tissue called what?

A

epimysium

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10
Q

The connective tissue coverings for skeletal muscle can fuse to make what structures?

A

tendons & aponeuroses

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11
Q

What is a tendon?

A

tough band of connective tissue that holds muscle to bone’s periosteum; holds 1 muscle to another or into skin

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12
Q

What is an aponeurosis?

A

tough, flat sheet of connective tissue

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13
Q

What is a fascia?

A

fibrous connective tissue that acts to compartmentalize muscles or separate them into groups

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14
Q

What are the 2 types of fascia?

A

superficial & deep

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15
Q

What is superficial fascia?

A

found between muscles & skin

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16
Q

What is a deep fascia?

A

found between muscles & organs & bones

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17
Q

Muscles attach to the body in at least 2 points which are what?

A

the origin & insertion

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18
Q

What is the origin?

A

the less movable point of attachment

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19
Q

What is the insertion?

A

the more movable point of attachment

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20
Q

What is the muscle’s action?

A

pulling the insertion closer to the origin; occurs when a muscle contracts

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21
Q

What is the prime mover?

A

the muscle in the group that completes most of the action

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22
Q

What are synergists?

A

“helper muscles” that aid the prime mover

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23
Q

What are antagonists?

A

muscles that perform an action opposite of the prime mover’s action

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24
Q

What can skeletal muscle cells also be called?

A

muscle fibers

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25
Q

What is a sarcolemma?

A

the cell membrane surrounding muscle cells

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26
Q

What is sarcoplasm?

A

the cytoplasm inside muscle cells; contains organelles & special protein fibers called myofibrils

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27
Q

What is sarcoplasmic reticulum?

A

special ER found in the sarcoplasm; stores Ca++ & pumps it into the sarcoplasm as needed

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28
Q

What are t-tubules (transverse tubules)?

A

hollow tubes that connect to the sarcolemma; when the muscle is stimulated, these tubes open for Na+ to rush in

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29
Q

What are myofibrils?

A

proteins used for muscle contraction; made of actin & myosin

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30
Q

What is actin?

A

thin filament made of g-actin which is globs of protein twisted around a threadlike core called nebulin (like beads on a string)

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31
Q

What is myosin?

A

thick filament that looks like 2 headed golf clubs bound together which interact with actin at myosin binding sites

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32
Q

What is a sarcomere?

A

sections in which myosin is arranged; it is the smallest contractile unit of muscle

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33
Q

What happens to Z-lines as muscle contracts?

A

they move closer together (Z-lines are the borders of a sarcomere)

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34
Q

What is anchored onto Z-lines? What happens to this structure when the muscle is stimulated?

A

actin; when stimulated, actin & myosin form cross bridges pulling the Z-lines closer together making the muscle shorten

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35
Q

What is tropomyosin?

A

a slick protein that blocks the actin’s myosin binding sites in a muscle at rest; it is held in place by another protein called troponin

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36
Q

What is the motor end plate?

A

the point in the muscle cell that acetylcholine goes to after diffusing across the synapse; then it is quickly broken down by acetylcholinesterase

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37
Q

What happens to the sarcolemma due to the presence of acetylcholine?

A

holes open & Na+ enters from the ECF; Na+ travels through the t-tubules to the SR

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38
Q

What does the SR do once Na+ enters it?

A

it responds by pumping Ca++ onto myofibrils

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39
Q

What does Ca++ do once it is released onto myofibrils?

A

it binds to troponin making it unstable; troponin falls away pulling tropomyosin off of actin’s myosin binding sites

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40
Q

What is step 6 of the sliding filament theory?

A

myosin’s heads attach to the newly exposed binding sites on the actin

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41
Q

What is step 7 of the sliding filament theory?

A

myosin’s heads pivot & pull actin which causes the sarcomere (Z-line to Z-line) to shorten

42
Q

What is step 8 in the sliding filament theory?

A

steps 6 & 7 only give a tiny bit of contraction so they must be repeated many times; this occurs through ATP which is used to break existing crossbridges so new ones can form

43
Q

What is rigor mortis?

A

occurs at death; if no ATP is available to break the crossbridges, the muscle is “frozen” in its contracted state

44
Q

What is the final step of the sliding filament theory?

A

when the desired contraction is complete, Ca++ is pumped back into the SR & troponin + tropomyosin return to actin, blocking the myosin binding sites until next time

45
Q

What is ATP?

A

provides the cell with lots of energy; adenosine triphosphate

46
Q

What is ADP?

A

adenosine diphosphate; formed through a chemical reaction called hydrolysis in which 1 phosphate molecule is broken away from ATP

47
Q

What are the 3 ways in which ATP is generated in muscles?

A

creatine phosphate, anaerobic, & aerobic pathways

48
Q

What is the creatine phosphate pathway?

A

a phosphate is broken from creatine phosphate, releasing a little bit of energy which provides about 8-10 seconds of muscle contraction; helps to maintain muscle tone

49
Q

What is the anaerobic pathway?

A

occurs without oxygen; glucose is rapidly broken down when oxygen is NOT present & its energy is transferred to ADP to form ATP

50
Q

In the anaerobic pathway, how much ATP is formed from 1 glucose molecule?

A

2 units of ATP; this is enough for high intensity contractions of a short duration

51
Q

What acid does the anaerobic pathway generate?

A

lactic acid

52
Q

Lactic acid diffuses into the blood which decreases the blood pH. What does this do?

A

stimulates respiratory centers in the brain, increasing breathing rates & depths

53
Q

What happens when lactic acid enters additional metabolic pathways?

A

it ultimately forms ATP & other molecules

54
Q

What contributes to muscle soreness & fatigue?

A

lactic acid

55
Q

What color are anaerobic cells?

A

light colored

56
Q

Why are anaerobic cells light colored?

A

they have a low concentration of mitochondria, a small amount of blood vessels in their fascicles, & a lack of myoglobin

57
Q

What is the aerobic pathway?

A

glucose is broken down inside mitochondria through chemical reactions that require oxygen which produce lots of ATP

58
Q

In the aerobic pathway, how much ATP is formed from 1 glucose molecule?

A

about 38 units of ATP but the reactions occur slowly, providing lots of energy for long-sustained contractions

59
Q

What acid does the aerobic pathway generate?

A

pyruvic acid which joins other metabolic pathways

60
Q

What color are aerobic cells?

A

dark colored

61
Q

Why are aerobic cells dark colored?

A

they have a high concentration of mitochondria, many blood vessels in their fascicles, & abundant myoglobin

62
Q

What is myoglobin?

A

similar to hemoglobin; a red pigment that transports oxygen within the cell

63
Q

What are myoblasts?

A

very mitotically active cells that form skeletal muscle; formed from stem cells in fetal development

64
Q

How do myoblasts form skeletal muscle cells?

A

they slow down their cell division & align in units where the new muscle will eventually be

65
Q

Is the new skeletal muscle cell formed from myoblasts mitotically active?

A

no; in order for muscle size to increase, the cells themselves must grow instead of dividing

66
Q

How can the new skeletal muscle grow in size?

A

by increasing the amount of myofibrils; this is controlled hormonally by growth hormones & androgens

67
Q

What are growth hormones?

A

produced by the pituitary gland; they cause growth of many tissues including muscle cells; these are the most active in children

68
Q

What are androgens?

A

sex hormones such as testosterone; increase the size of a muscle cell by increasing the amount of myofibrils; occurs in adults & teens past puberty

69
Q

What is fibrosis?

A

a process when connective tissue will fill in a damaged area of a skeletal muscle if it is cut/torn

70
Q

Is muscle that is repaired through fibrosis strong?

A

no; it is weaker than before the damage because connective tissue can’t contract

71
Q

Are myoblasts still active in adults?

A

a few; these could be useful to help repair skeletal muscle damage

72
Q

What is the ANS?

A

a component of the efferent (motor) pathway; controls smooth muscle, cardiac muscle, & glands; divided into the sympathetic & parasympathetic divisions

73
Q

What is the sympathetic division?

A

speeds up the action of the tissues that spend energy & slows down the ones that acquire energy

74
Q

What is the parasympathetic division?

A

speeds up the action of tissues that acquire energy & slows down the ones that spend energy

75
Q

What is dual innervation?

A

the ANS effectors are innervated by both sympathetic & parasympathetic neurons; this provides precise control

76
Q

What are the 3 components of the ANS divisions (sympathetic & parasympathetic)?

A

preganglionic neuron, ganglion, & postganglionic neuron

77
Q

What is the preganglionic neuron?

A

it has dendrites & cell bodies in the brain & spinal cord; their axons exit the brain & cord to travel to a ganglion

78
Q

What is the ganglion?

A

clumps of cells bodies where preganglionic neurons synapse with postganglionic neurons

79
Q

What is the postganglionic neuron?

A

have cell bodies in ganglia & their axons end in effectors

80
Q

What is another term for the parasympathetic division?

A

the craniosacral division

81
Q

Why is the parasympathetic division also called the craniosacral division?

A

the cell bodies & dendrites of the preganglionic neurons are located in cranial nerves 3,7,9,10 & in the sacral regions of the spinal cord; their axons travel to ganglia & release acetylcholine

82
Q

What is another term for the ganglia in the craniosacral/parasympathetic division?

A

terminal ganglia; they are located near or inside effector tissues; this is the site of synapse between pre & post ganglionic neurons

83
Q

What are characteristics of the postganglionic neurons in the craniosacral/parasympathetic division?

A

the cell bodies & dendrites are located in terminal ganglia; they have very short axons that travel to effectors to release acetylcholine

84
Q

What is another term for the sympathetic division?

A

thoracolumbar division

85
Q

Why is the sympathetic division called the thoracolumbar division?

A

the cell bodies & dendrites of the preganglionic neurons are located in the lateral gray horns of the thoracic & lumbar sections of the spinal cord

86
Q

Where are the axons of the preganglionic neurons for the sympathetic division?

A

they exit as part of the ventral roots & travel a short distance to ganglia where they release acetylcholine

87
Q

What are the 2 types of ganglia in the sympathetic division?

A

prevertebral & sympathetic trunk/chain

88
Q

What are the prevertebral ganglia?

A

part of the sympathetic division; located anterior to vertebrae

89
Q

What is the sympathetic trunk/chain ganglia?

A

part of the sympathetic division; located lateral to vertebrae; these house postganglionic neurons

90
Q

Where can the axons of postganglionic neurons in the sympathetic division be found?

A

they are very long & they exit ganglia & travel to effectors where they release norepinephrine

91
Q

What are cholinergic neurons?

A

neurons of the ANS that release acetylcholine

92
Q

Do the effects of acetylcholine last long?

A

no; it is quickly broken down by acetylcholinesterase

93
Q

What are adrenergic neurons?

A

neurons of the ANS that release norepinephrine

94
Q

Do the effects of norepinephrine last long?

A

yes; it is broken down by a lot of enzymes so it happens slowly

95
Q

What is unique about norepinephrine effectors?

A

they have alpha & beta receptors

96
Q

What is sympathetic stimulation?

A

“fight or flight” response

97
Q

What can sympathetic stimulation increase?

A

heart rate, contraction force, blood pressure, breathing rates/depths, & blood sugar levels (ensures adequate ATP generation)

98
Q

What is epinephrine?

A

adrenaline; causes beta receptors to be more sensitive to norepinephrine; released by the adrenal glands which are activated from sympathetic stimulation

99
Q

What happens to blood vessels during sympathetic stimulation?

A

blood vessels in the skin, digestive system, & urinary system constrict; blood vessels that go to skeletal muscle, heart, & brain relax

100
Q

What else occurs from sympathetic stimulation?

A

the smooth muscle of bronchial tubes relaxes & pupils dilate

101
Q

What are the parasympathetic effects?

A

“rest & digest” response; the reverse of sympathetic effects

102
Q

Which effects last longer, sympathetic or parasympathetic?

A

sympathetic lasts longer because norepinephrine is broken down slower; parasympathetic is short-lived because acetylcholine is broken down faster to easily shift into sympathetic mode

A&P I Lecture (6 decks)

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