Brainscape's Knowledge GenomeTM

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


See full index

Physiology final > Skeletal Muscle > Flashcards

Skeletal Muscle Flashcards

1
Q

what is the neuromuscular junction

A

where the neuron connects to the muscle

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

What happens at the neuromuscular junction

A
  1. The action potential reaches the terminal bouton of axon
  2. voltage gated calcium channels open up which stimulates the release of the neurotransmitter ACH
  3. ACH binds to the nicotinic cholinergic receptor, which allows for Na+ to enter the muscle cells
  4. this causes an action potential in the muscle fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the motor end plate

A

a specialized region of the muscle fibers plasma membrane with many nicotinic cholinergic receptors

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

What is the neurotransmitter used in the neuromuscular junction

A

Acetycholine, the only neurotransmitter in the somatic nervous system

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

what ion channels play an important role in excitation of muscle fibers

A 
voltage gated calcium channels (release ACH)
Cation channels (allow for depolarization of muscle)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does acetylcholinesterase do

A

it breaks down the ACH in the synaptic cleft

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

Where is acetylcholinesterase located

A

between the invaginations of the motor end plate

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

Why is acetylcholinesterase important

A

breaking down the ACH terminates the excitatory signal and causes the muscle to relax

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

once an action potential is generated in muscle where does it spread

A

over the muscle fiber sarcolemna in all directions

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

what is excitation-contraction coupling

A

it’s the sequence of events that connects the excitation of muscle fibers to their contraction

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

what is a T-tubule

A

invaginations in the sarcolemna that extend deep into the muscle fibers and run along the myofibrils

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

What is the sarcoplasmic reticulum

A

smooth ER that stores calcium which is necessary for muscle contraction

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

What are the steps of Excitation-contraction coupling

A
  1. ACH is realeased from neuron which causes depolarization of the muscle fiber
  2. the action potential runs down the sarcolemna and dives down into the T-tubules
  3. in the T-Tubules the DHP receptor is activated by the action potential
  4. the DHP receptor pulls on the Ryanodine receptor.
  5. the Ryanodine receptor opens, allowing calcium to leave the sarcoplasmic reticulum
  6. Calcium binds to troponin exposing the myosin binding sites on actin
  7. crossbridge cycle leads to muscle contraction
  8. Ca+ is pushed back into sarcoplasmic reticulum by Ca+ ATPase pumps
  9. tropomyosin blocks the myosin binding sites on actin
  10. muscle relaxes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the organization of skeletal muscle from largest to smallest

A
  1. Muscle
  2. Fascicle
  3. muscle fiber (myofiber)
  4. myofibril
  5. Sarcomere
  6. Myosin
  7. Actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a fascicle

A

A bundle of muscle fibers

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

what is a muscle fiber

A

an individual muscle cell, made up of many myofibrils

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

What is a myofibril

A

a rodlike thing in a muscle cell that houses the sarcomere and is surrounded by the sarcoplasmic reticulum

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

What is a sarcomere

A

it’s the functional unit of muscle. It’s made up of myosin and actin

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

What are the bands/zones/lines on the sarcomere (name and what makes them)

A
  1. A band - Where any myosin is found (DARK)
  2. I band - where ONLY actin is found (Light)
  3. H zone - Where ONLY myosin is found (Medium)
  4. M line - scaffolding protein holding myosin together
  5. Z line - scaffolding protein holding actin together
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how do we define one sarcomere

A

area from one z line to another.

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

What happens to sarcomere zones/lines/bands during contraction

A
  1. A band doesn’t change
  2. I band shrinks
  3. H zone shrinks
  4. M line stays stationary
  5. z lines move closer together`
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What causes muscle to look striated

A

the bands and zones of the sarcomere

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

What are the layers of connective tissue in skeletal muscle

A

connective tissue wraps up each muscle fiber, fascicle, and surrounds the whole muscle. When the muscle contracts it pulls on the connective tissue around it, which pulls on the tendon (where all of the connective tissue meets up) and pulls the bones closer together.

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

What is cross bridge cycling

A

its the interaction between actin and myosin and how it all works

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

what role does calcium play in cross bridge cycling

A

calcium binds to troponin which pulls tropomyosin off of myosin binding sites of actin allowing myosin heads to bind and cause contraction

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

What is the thick filament

A

Myosin

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

What is Myosin made of

A

Many myosin proteins

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

how many thin filaments surround one thick filament

A

6

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

Does Myosin use ATP

A

yes, it breaks it down and releases the energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the thin filament

A

Actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is actin made up of

A

Many actin molecules (with myosin binding sites)

Troponin and tropomyosin proteins

32
Q

What is tropomyosin

A

a strand-like protein that covers myosin binding sites on actin

33
Q

what is troponin

A

a 3 complex protein, one binds calcium, one binds actin, and one binds tropomyosin

34
Q

what are the steps of cross bridge cycling

A
  1. Calcium in the cytoplasm binds to troponin, which pulls tropomyosin off of myosin binding sites
  2. Myosin head binds to actin triggering power stroke
  3. Power stroke occurs as myosin pulls actin towards the middle of the sarcomere (triggers ADP and Pi are released)
  4. Rigor sets in as myosin ins’t cocked back and is still hooked onto actin
  5. ATP binds to myosin head causing it to release from Actin
  6. ATP is hydrolyzed to ADP and Pi, causing myosin to become cocked
  7. Myosin rebinds to actin and continues to do so until calcium is absent
35
Q

What happens when the muscle fibers isn’t getting more action potentials

A
  1. DHP receptor closes
  2. Ryanodine receptor closes (no more Ca+ leaves)
  3. The Ca+ ATPase pumps the calcium back into the sarcoplasmic reticulum
  4. Calsequestrin holds on to calcium in the lateral sacs, allows for more calcium to be stored
36
Q

for what reasons is ATP needed for in relaxation

A
  1. The Ca+ ATPase uses ATP to pump up Ca+

2. Myosin releasing from Actin requires ATP

37
Q

What is a Muscle twitch

A

a quick weak contraction caused by one action potential in the muscle

38
Q

What is the latent period

A

the delay between the start of the action potential and the start of the twitch

39
Q

what determines the force production done by a single muscle fiber

A
  1. Frequency of stimulation
  2. Fiber Length
  3. Fiber diameter (Greatest indicator of force)
40
Q

What about muscle twitch frequency

A
  1. They last longer than action potentials

2. if they fire in quick enough succession then they summate to complete tetanus

41
Q

How does fiber length increase force by one muscle fiber

A

The closer that it is to normal length the stronger it is. too long means that many myosin heads don’t connect, and too short means that the thin filaments run into each other.

42
Q

what is serca

A

The Ca+ ATPase that pumps Ca+ from cytosol into sarcoplasmic reticulum

43
Q

What is a motor unit

A

one motor neuron and all of the muscles it innervates. (all of the muscle fibers are spaced out, not next to each other)

44
Q

what determines how much force a muscle exerts

A

each muscle fiber only pulls with one force, so more force means more motor neurons are required.

45
Q

How is motor neuron recrutement organised

A

The smaller motor neurons are depolarized first because its easier. smallest to largest.

46
Q

what is isotonic contraction

A

when tension doesn’t change but the muscle shortens

47
Q

what is isometric comtraction

A

When the length of the muscle doesn’t change but tension does

48
Q

What is Myasthenia Gravis

A

Autoimmune attack on nicotenic receptors, can’t allow muscle cells to retire

49
Q

what causes the latent period

A
  1. takes time for it all to happen

2. taughtening of the tendons

50
Q

What is tetanus

A

when the muscle twitches are close enough together that there is not dip in Ca++ levels. steady contraction

51
Q

how does fiber diameter determine force

A

a larger diameter = more myofibrils = more force

52
Q

what is an eccentric contraction

A

when the muscle is contracting but lengthening

53
Q

what is a concentric contraction

A

when a muscle is contracting and shortening

54
Q

what are the two ways to classify muscle fibers

A
  1. Speed of contraction (Fast twitch or slow twitch)

2. Major pathway of ATP production (glycolyic or oxidative)

55
Q

What is a fast twitch fiber

A

it’s muscle fiber that has a short period of time between neuron firing and peak tension

56
Q

What is a slow twitch fiber

A

it’s a muscle fiber that has a long period of time between stimulation and peak tension

57
Q

what is a glycolyic muscle fiber

A

a muscle fiber with few Mitochondria, therefor low ATP production. They also have more glycolytic enzymes. They are usually larger in diameter, with less blood vessels

58
Q

What is a oxidative muscle fiber

A

a muscle fiber with many mitochondria, therefor they produce a lot of ATP. They have less glycollytic enzymes. they are usually smaller in diameter and more vasculated.

59
Q

What is a type I muscle fiber and when is it recruted

A

its a slow-oxidative fiber, and it’s recruited for posture and endurance

60
Q

What is a type IIa muscle fiber and when is it recruited

A

it’s a fast-oxidative fiber, and it’s recruited for endurance (walking and jogging)

61
Q

What is a type IIx muscle fiber and when is it recruited

A

its a fast-glycolytic fiber and it’s recruited for max effort (sprint type activity)

62
Q

what percentages of type I and type II fibers does the average person have

A

50-50

63
Q

what percentages of type I and type II fibers does a sprinter have

A

type 1 - 30

type 2 - 70

64
Q

what percentages of type I and type II fibers does a long distance runner have

A

type 1 - 70

type 2 - 30

65
Q

can fiber type be changed with exercise training

A

Yes (but you can’t go from slow to fast)

66
Q

can fiber type de changed when you become more sedentary

A

yes (can’t go from fast to slow)

67
Q

in what order are the fiber types recruited

A

slow-oxidative - type I
fast-oxidative - type IIa
fast-glycolytic - type IIx

68
Q

which types of fibers get fatigued the quickest

A

type IIx then type IIa then type I

69
Q

how does chronic endurance exercise increase a muscle resistance to fatigue

A
  1. it increases mithochondria so that ATP can be produced more quickly
  2. more mithochondria = less lactate
  3. greater relative contribution of fat
70
Q

AMPK and calcium in resistance to muscle fatigue

A

?

71
Q

How does resistance training lead to muscle hypertrophy and increased strength

A
  1. it stimulates anabolic signaling (mTor)
  2. that leads to protein synthesis
  3. that leads to hypertrophy

also

  1. it activates satellite cells
  2. which leads to muscle hypetrophy/myogenesis

4 .the larger the muscles are the stronger they are

72
Q

mTor is important for what

A

muscle growth

73
Q

What is the role of satelite cells

A

they basically add onto muscle cells to make them more nucleated, they are needed for hypertrophy

74
Q

what is hypertropy

A

increased cell size

75
Q

what is hyperplasia

A

increased number of cells

Physiology final (10 decks)

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