Brainscape's Knowledge GenomeTM

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


See full index

Physiology Block 1- Cardiovascular Physiology > Skeletal Muscle > Flashcards

Skeletal Muscle Flashcards

1
Q

What is the largest tissue in the body that is responsive to insulin?

A

Skeletal muscle

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

When seen in the blood, what enzyme is indicative of some form of damage to the structural integrity of a muscle?

A

Creatine kinase

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

What sign of lower extremity weakness is seen as children push themselves up?

A

Gower sign

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

How does a mutation in the dystrophin gene contribute to increased creatine kinase blood levels?

A

Dystrophin complexes links actin of the muscle fibril to the extracellular matrix to provide strength and support to the cell membrane, and when thisis mutated the cell membrane will lose integrity and creatine kinase will leak out

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

In which condition does an individual developm antibodies to cholinergic receptors?

A

Myasthenia Gravis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

To which cholinergic receptor will ACh bind on the motor plate?

A

Nictonic (N1) receptor

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

Binding of acetylcholine to its receptor on the motor plate triggers what immediate event?

A

The opening of ligand-gated Na+ channel

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

The influx of what ion into the axon terminal is required for synaptic release of acetylcholine?

A

Ca2+

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

What structure of the skeletal muscle cell is especially helpful in propagating an action potential?

A

T-tubules

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

The influx of what ion into the muscle cell is responsible for depolarization? What channels are subsequently opening by the wave of depolarization?

A

Sodium; Opens votalge-gated Na and K channels

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

Where are dihydropyridine (DHP) receptors located within the cell? What type of channel are they?

A

The sarcolemma; L-type voltage-gated Ca channel

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

What is the biochemical function of dihydropyridine receptors?

A

Activation of ryanodine (RyR2) receptors

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

Where are ryanodine (RyR2) receptors located within the cell? What type of receptor is it?

A

The sarcoplasmic reticulum; Calcium channels?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the chemical result of the opening of ryanodine receptors?

A

A 100-fold increase in cytosolic [Ca++]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What causes the depolarization to end?

A

Degradation of ACh by acetylcholinesterase

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

What is the advantage of having action potentials that are as narrow as those in muscle depolarization?

A

It allows the membrane to be stimulated again and elicit another action potential that wil lincrease the strength of contraction

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

What displaces tropomyosin I from the myosin-binding site on actin filaments?

A

Cytosolic calcium binds to troponin C, which undergoes a conformational change and causes a drop in tropinin I concentration attached to actin and displaces tropomyosin

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

The binding of ATP to the myosin head causes what conformational change?

A

The release of myosin from actin

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

What causes the rapid formation of the cross bridge and the subseqeunt power stroke?

A

The release of Pi from the myosin head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When is ADP released from the mysoin head? What is the subsequent action?

A

It is released at the end of the power stroke and then the myosin goes back to a rigor state

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

What biochemical event results in muscle relaxation?

A

Decrease in cytosolic calcium

22
Q

What is the mechaism of cytosolic calcium decrease?

A

Sodium/ calcium exchanger on the plasma membrane, and reuptake into the sarcoplasmic reticulum

23
Q

True or false: Energy is required for muscle relaxation?

A

True

24
Q

What chaperone proteins bind Ca2+ in the sarcoplasmic reticulum?

A

Calsequestrin and calreticulin

25
Q

What are the early symptoms of malignant hyperthermia?

A

Muscle rigidity, tachycardia, hyperthermia, metabolic acidosis, tachypnea, sweating

26
Q

Malignant hyperthermia can be caused by genetic defect in what two kinds of molecules?

A

CACNA1s: DHP receptor and RyR1: ryanodine receptor

27
Q

What is the physiology underlying malignant hyperthermia?

A

The release of Ca2+ into the cytosol is exaggerated and reuptake into the SR is delayed

28
Q

What is the most common form of motor neuron disease in adults?

A

Amyotrophic Lateral Sclerosis

29
Q

What causes ALS?

A

Progresssive motor neuron degeneration

30
Q

What is the pharmologic mechanism of curare?

A

Competitive inhibition of ACh receptor

31
Q

What is the mechanism of botox?

A

Interferes with ability of ACh containing vesicles to bind to presynaptic plama membrane, decreasing synaptic release of ACh and preventing muscle contraction

32
Q

What are the two ways skeletal muscle increases strength of contraction?

A

Temporal and spatial summation

33
Q

What is temporal summation? What is the result of no relaxation between stimuli?

A

An increase in the frequency of stimulation; tetanus

34
Q

What is spatial summation?

A

An increase in the number of motor units recruited

35
Q

What physical characteristic of a muscle is related to the tension of a muscle fiber? When is tension maximal?

A

Length of the muscle fiber; tension is maximal at resting length

36
Q

What is the maximal resting length of skeletal muscle?

A

The point where the number of cross-bridges is maximized

37
Q

What are the three sources of ATP for skeletal muscle contraction?

A

ATP phosphorylation (creatine kinase), Oxidative phosphorylation, glycolysis

38
Q

Most energy used in working out skeletal muscles comes from where?

A

Oxidative phosphorylation

39
Q

What is the preferred energy source of red muscle fibers?

A

Oxidative phosphorylation

40
Q

What is the preferred energy source of white muscle fibers?

A

Glycolysis

41
Q

What are the two main factors used to categorize skeletal muscle fibers?

A

Energy metabolism and rate of force production and shortening velocity (how quickly cells contract)

42
Q

What are type I skeletal muscle fibers?

A

Slow-twitch oxidative

43
Q

What are type IIA skeletal muscle fibers? Type IIX?

A

Fast-twtich oxidative; Fast-twitch glycolytic

44
Q

What property determines whether or not a skeletal muscle is slow or fast twitch?

A

Myosin-ATPase

45
Q

At approximately what point in continuous moderate exercise will fat be utilized in significant amounts to fuel skeletal muscle?

A

After 30 min

46
Q

What is muscle fatigue?

A

The decreased skeletal muscle tension following previous contractile activity

47
Q

What type of skeletal muscle fibers are the most resistant to fatigue?

A

Slow -twitch oxidative fibers

48
Q

What type of skeletal muscle fiber would be primarily used in sprinting?

A

Fast glycolytic

49
Q

What is the effect of obesity and Type 2 diabetes on skeletal muscle?

A

Decreases the oxidative capacity and increases triglyceride content

50
Q

True or false: Skeletal muscle cells have gap junctions?

A

False

Physiology Block 1- Cardiovascular Physiology (17 decks)

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