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Flashcards in Gross Q1 Deck (84):
1

What is myology

branch of anatomy that deals with skeletal muscular system

2

how much of body weight is skeletal muscle

40-50 percent

3

Functions of skeletal muscle

Movement,
stability,
communication,
control of body openings and passages, and
heat production

4

what other systems is skeletal muscle closely interrelated with?

bones and joints, respiratory and digestive systems, the integumentary system, and the nervous system

5

what is a muscle cell called?

a muscle fiber

6

muscle fibers are grouped into bundles known as...

fasciculi

7

what are muscles fibers and fasciculi bound together by?

connective tissue

8

Functions of connective tissue in muscle

1. connect muscle to bone or other structures
2. provide route for nerves and blood vessels to supply muscle
3. Provide non-contractile framework to transmit contraction to a bone

9

Three layers of connective tissue in skeletal muscle

1. Epimysium
2. Perimysium
3. Endomysium

10

Function of Epimysium

wraps around the muscle fiber

11

Function of perimysium

wraps around the fascicle

12

Function of endomysium

wraps the muscle---> becomes tendon

13

T/F? There are multiple nuclei in a muscle fiber

True

14

what is a myofilament?

contractile unit of muscle, every muscle cell will contain dozens to hundreds of these.

15

What is a muscle fiber's membrane called?

a sarcolemma

16

how much larger are adult muscles than neonate muscles?

10x larger

17

Hypertrophy

Increase in the size of each individual muscle fiber

18

Hyperplasia

Increase in the number of muscle fibers

19

what is the cytoplasm of a muscle cell called?

sarcoplasm

20

type I muscle fibers

Long, sustained muscle contraction is required. Associated with endurance. Specialize in aerobic metabolism

21

Type II muscle fibers

used in quick powerful activities- speed and strength. Associated with anaerobic metabolism.

22

called a fast twitch muscle fiber

Type II fibers

23

fatigue resistent fibers

Type I

24

Muscle fiber with Extensive capillary beds

Type I

25

muscle cell that uses more glycogen, less fatty acids

Type II

26

fiber that atrophies with aging

Type II

27

fiber type with more mitochondria

Type I

28

intermediate fibers

b/w type I and type II. They contract faster than type I but slower than type II. greater fatigue resistance but resemble type II fibers.

29

sarcoplasmic reticulum

an elaborate, tubular network that stores and transports Ca++ to myofibrils

30

transverse tubules

invaginations in the sarcolemma, allow action potentials to make their way into the muscle fibers and to the myofibrils

31

myoglobin

red protein pigment found in sarcolemma. almost indistinguishable from hemoglobin. stores O2 needed for aerobic respiration. greater affinity for O2 than hemoglobin

32

myofibril

contractile apparatus of the muscle fiber

33

I-Bands

light areas at the ends of sarcomeres

34

A-bands

the entire dark part of the contractile unit

35

H-bands

light areas in the middle of the A-bands

36

M-line

Dark band in the middle of the the A-band

37

Z-line

Dark line in the middle of the I-band

38

sarcomere

smallest functional unit of muscle, runs Z-line to Z-line

39

Actin

contractile protein mainly found in the I bands

40

Myosin

contractile protein mainly found in the A-bands

41

process of muscle contraction

nerve sends action potential, acytlcholine diffused across neuromuscular junction, binds to receptors. action potential travels down t-tubules, stimulates release of Ca++ from sarcoplasmic reticulum. Ca++ binds to troponin on actin filaments, changes the shape of tropomyosin and exposes myosin binding site. ATP allows myosin to interact with actin and cause a muscle contraction.

42

T/F? 1 ATP is required for myosin to bind to actin, but 1 ATP is not required to release actin.

false
 

43

preferred fuel source for aerobic metabolism

fatty acids

44

how are fatty acids stored in fat cells?

triglycerides

45

Phase One of cardiovascular exercise

lasts for a couple minutes. Creatine phosphate and glycogen are primary fuel. 20% of glycogen will be depleted

46

Phase two

shift to aerobic metabolism to utilize fatty acids and make ATP

47

Phase three

As fatigue sets in, shift back to anaerobic cycle to make ATP. Remaining glycogen is utilized. Lactic acid accumulates.

48

Ergogenic aid

a technique or substance used for the purpose of enhancing performance

49

Glycogen/Carb loading

Aims to increase intramuscular glycogen
day 1: work to exhaustion, deplete glycogen
days 2-4: continue to exercise. eat diet low in carbs
days 5-7: no exercise, high carb diet.

50

Side effects of carb-loading

dizziness, light-headedness, lethargy, lower mental acuity, increase in weight due to increased glycogen and water in muscles

51

Caffeine benefits

2 cups of coffee used 1:30 before a race can allow fatty acids to be broken down more efficiently. delays phase 3

52

caffeine cons

it is a diuretic and can cause nervousness

53

Blood doping process

blood cells are drawn from the athlete and stored several months before. on the day of the race, cells are reintroduced into the blood to allow greater O2 carrying capacity

54

Doping risks

can cause rashes and fevers, acute hemolysis, transmission of viruses and can cause fluid buildup leading to kidney damage or clotting

55

Erythropoetin (EPO)

hormone that causes production of red blood cells in bone marrow. can thicken blood to dangerously high levels

56

Anabolic steroids

synthetic forms of testosterone that cause anabolic effects but less androgenic effects. less rapidly broken down than regular testosterone.

57

oil-based steroids

injected with fewer side-effects but can be tested months after stopping

58

water-based steroids

taken in pill form with more side-effects. cleared from system in 3-4 weeks.

59

patches/gels

another way to administer steroids. more androgenic effects

60

pyramiding

user starts at a low dosage, raises to a peak and then tapers down the amount being taken

61

stacking

user takes several forms of the drug. Both oil and water based

62

short term side effects of steroids

headaches, dizziness and nausea, acne, shrinkage of testes, gynecomastia, tendon damage

63

long term side effects of steroids

issues with cardiovascular system, digestive system, prostrate cancer, endocrine system

64

steroid side-effects in females

increase clitoral size, decrease mammary gland size, develop facial hair, voice deepen, tendon damage

65

steroid side-effects in adolescents

premature closing of growth plates --> shortened stature.

66

anabolic steroids work by...

increasing growth hormone production,
increasing protein synthesis and decreasing protein breakdown.

67

Chemical composition of muscle

75% water
20% protein (mainly myosin)
5% other

68

What nerves are supplied to every muscle cell?

motor nerve (efferent) fiber and a sensory (afferent fiber)

69

Nerve fibers enter and leave a muscle via the ______ _______ components of the muscle

connective tissue

70

What is the motor unit?

a single neuron and all the muscle fibers it innervates. It is the smallest part of a muscle that can contract independently

71

What determines the precision of muscle?

the smaller the motor unit the more precise its movements will be

72

Where does the motor unit originate and terminate?

Originates: in the ventral horn of the gray matter in the CNS.

CNS-->PNS-->muscle fiber sarcolemma

Terminates: in the sarcolemma of the muscle fiber (terminal end)

73

What is the PRE-synaptic portion of the neuromusclular junction (NMJ)?

The nerve ending

74

What is the POST-synaptic portion of the NMJ?

sarcolemma of the muscle fiber

75

What is the SYNAPTIC CLEFT ?

space b/w pre and postsynaptic portions where ACH is released.

76

__________ is released at the presynaptic portion of the NMJ via a __________ potential.

Acetylcholine (ACH) ; action potential

77

Once ACH completes its binding, __________ is the enzyme that breaks down ACH.

Acetylcholinesterase (ACHe)

78

ACHe degrades ACH into _______ & _______.

acetate ; choline

79

What is Myasthenia Gravis?

most common NMJ autoimmune disorder. Rogue antibodies damage ACH receptor sites on the sarcolemma. Begins affecting muscles supplied by cranial nerves (e.g. eye/face muscles). May progress to extremities.

Patients may suffer tumor to the thymus gland (removal may = remission)

80

A pregnant women suffering from Myasthenia Gravis has a ____% chance that her infant develops ________ neonatal myasthenia gravis

25% ; Transitional Neonatal Myasthenia Gravis

81

How does Nicotine affect the NMJ?

Nicotine competes with ACH in receptor sites binding. Its actions are more prolonged than ACH

82

How does Snake Venom affect the NMJ?

prevents ACH from binding to receptor sites. Unlike nicotine...snake venom doesn't cause action potential to occur.

83

How does Organophosphates affect the NMJ?

inactivates ACHe. ACH cannot be broken down and accumulates in postsynaptic NMJ. Examples include parathion & malathion found in insecticides.

84

How does Botulin Toxin affect NMJ?

released from bacteria: clostridium botulinum . causes food poisoning...botulism.

Blocks release release of ACH from presynaptic portion of NMJ. First affects cranial nerves and can be fatal.