Brainscape's Knowledge GenomeTM

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


See full index

Electrophysiology > Muscle physiology > Flashcards

Muscle physiology Flashcards

1
Q 
The primary neurotransmitter at the neuromuscular junction is
	A)	dopamine.
	B)	adrenaline.
	C)	acetylcholine.
	D)	histamine.
	E)	serotonin.
A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q 
Arrange the following in the proper order in which they occur at the pre-synaptic side of a neuromuscular junction.
1. Calcium ions are released
2. Action potential arrives at the presynaptic terminal
3. Neurotransmitter is released
	A)	1, 2, 3
	B)	2, 1, 3
	C)	2, 3, 1
	D)	3, 2, 1
	E)	3, 1, 2
A

B

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

Arrange the following in the proper order in which they occur at the post-synaptic side of a neuromuscular junction.
1. Action potential is propagated over the muscle cell membrane
2. Depolarization of the post-synaptic membrane
3. Sodium ions move into muscle cell
A) 1, 2, 3
B) 2, 1, 3
C) 2, 3, 1
D) 3, 2, 1
E) 3, 1, 2

A

D

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

The area between the pre-synaptic nerve cell and the post-synaptic muscle cell is termed the synaptic cleft.
A) True
B) False

A

A

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

Receptors that bind the neurotransmitter at the post-synaptic cell membrane are voltage-gated.
A) True
B) False

A

B

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

Thick filaments –composed of __

Thin filaments – composed of ___

A

myosin (mataba)

actin , troponin and tropomyosin (tropang thin).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. The portion of the myofibril that lies between two successive Z disc is called
    a. sarcolemma
    b. sarcoplasm
    c. sarcomere
    d. sarcoplasmic reticulum
    e. sarcoid
A

C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. The thin myofilament is composed of the following structures except
    a. titin
    b. troponin
    c. tropomyosin
    d. fibrillar/filamentous actin
    e. globular actin
A

A

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

single , short contraction reflecting stimulation of some motor units in a muscle .

A

twitch

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

time between stimulus and responding muscle contraction .

A

latent period

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

During his period immediately following contraction , a muscle can not respond

A

refractory period

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

describes the addition of individual twitch contractions to increase the intensity of overall muscle contraction.

A

force summation

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

Smaller fibers- first to be stimulated because they are more excitable

As the strength of the signal increases, more motor units are excited in addition to larger ones.

As more and larger motor units are activated, the force of muscle contraction becomes progressively stronger.

A

Multiple fiber summation following size principle

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

An action potential arriving at the presynaptic terminal causes…
A) voltage-gated sodium ion channels to open, and sodium ions to diffuse into the cell.
B) voltage-gated sodium ion channels to open, and sodium ions to diffuse out of the cell.
C) voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell.
D) acetylcholine to diffuse into the cell.
E) ligand-gated sodium channels to open, and sodium ions to diffuse out of the cell.

A

C

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

In the neuromuscular junction, acetylcholine…
A) diffuses across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber.
B) is actively transported across the synaptic cleft and binds to acetylcholine receptors on the postsynaptic muscle fiber.
C) diffuses across the synaptic cleft and causes calcium ions to diffuse into the postsynaptic muscle fiber.
D) diffuses across the synaptic cleft and causes sodium ions to diffuse out of the postsynaptic muscle fiber.
E) is actively transported across the synaptic cleft and causes calcium ions to diffuse into the postsynaptic muscle fiber.

A

A

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

The neurotransmitter in the neuromuscular junction…
A) causes ligand gated calcium channels in the muscle fiber to increase their permeability to calcium, which depolarizes the postsynaptic membrane.
B) causes ligand gated sodium channels in the muscle fiber to increase their permeability to sodium, which depolarizes the postsynaptic membrane.
C) increases the calcium ion permeability of the presynaptic membrane.
D) increases the sodium ion permeability of the presynaptic membrane.
E) depolarizes the presynaptic membrane by increasing the permeability of sodium ions.

A

B

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

Acetylcholine is broken down into acetic acid and cholinesterase by choline.
A) True
B) False

A

B

18
Q

Once threshold is reached on the postsynaptic membrane, an action potential is generated and propagated over the muscle cell membrane.
A) True
B) False

A

A

19
Q 
An action potential enters a neuron...
	A)	by diffusion.
	B)	by the T-tubules.
	C)	by the sarcolemma.
	D)	by the sarcoplasmic reticulum.
	E)	by the actin myofilament.
A

B

20
Q 
What structures do the calcium ions bind to when muscle contraction is initiated?
	A)	the actin myofilament.
	B)	the troponin molecule.
	C)	the tropomyosin molecule.
	D)	the sarcoplasmic reticulum.
	E)	the sarcolemma.
A

B

21
Q

Cross bridges form between…
A) troponin and tropomyosin.
B) calcium and sodium.
C) the sarcolemma and the sarcoplasmic reticulum.
D) the T-tubules and the sarcolemma.
E) the actin filaments and the myosin heads.

A

E

22
Q

An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum.
A) True
B) False

A

B

23
Q

In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm.
A) True
B) False

A

B

24
Q

Each actin filament is composed of
A) a single strand of actin molecules.
B) two strands of actin molecules wrapped together.
C) three strands of actin molecules wrapped together.
D) four strands of actin molecules wrapped together.
E) hundreds of strands of actin molecules wrapped together.

A

B

25
Q

As actin and myosin filaments slide past each other during muscle contraction,
A) actin filaments shorten, while myosin filaments do not.
B) myosin filaments shorten, while actin filaments do not.
C) either actin or myosin filaments shorten, but not both at the same time.
D) both actin and myosin filaments shorten.
E) neither actin nor myosin filaments shorten.

A

E

26
Q

Which of the following statements about the “heads” of the myosin molecules is TRUE?
A) they form permanent links with actin filaments
B) they can attach to different sites on the actin filament
C) they straighten the myosin filaments
D) they allow the myosin filaments to wrap around each other
E) none of the above

A

B

27
Q

Each myosin protein has a globular head that extends outward from the myosin filament.
A) True
B) False

A

A

28
Q

Unflexing of the myosin head requires ATP.
A) True
B) False

A

A

29
Q

Muscle contraction is caused by
A) actin filaments sliding past each other.
B) myelin filaments sliding past each other.
C) myosin filaments sliding past each other.
D) actin filaments sliding past myelin filaments.
E) actin filaments sliding past myosin filaments.

A

E

30
Q

Which of the following statements about H zones and I bands is TRUE?
A) the H zones contain only myosin, while the I bands contain only actin
B) the H zones contain only actin, while the I bands contain only myosin
C) the H zones contain only myosin, while the I bands contain both actin and myosin
D) the H zones contain both actin and myosin, while the I bands contain only actin
E) the H zones and the I bands each contain both actin and myosin

A

A

31
Q

During muscle contraction
A) the A band remains the same and the I band narrows.
B) the I band remains the same and the A band narrows.
C) both the A band and I band remain the same.
D) both the A band and I band narrow.
E) both the A band and I band become wider.

A

A

32
Q

In a contracting muscle the Z lines come closer together.
A) True
B) False

A

A

33
Q

In a relaxed muscle, the H zone is at its narrowest width.
A) True
B) False

A

B

34
Q
  1. the following lines/ zones disappear during maximum skeletal contraction
    a. A band and M line
    b. A band and H zone
    c. I band and M line
    d. i band and H zone
    e. i band and z disc
A

D

35
Q
  1. in the sliding filament theory, which of the following statements is correct?
    a. prior to contraction, the myosin head hydrolyze GTP into the GDP + Pi
    b. the myosin head binds to tropomyosin to form cross bridges
    c. the myosin cross bridges will rotate from the center of the sarcolemma
    d. the binding of an ATP molecule causes detachment of the myosin head
    e. all are correct
A

D

36
Q

If muscle fibers are composed of a series of sarcomeres laid down next to one another, what happens to the length of the sarcomeres when muscle fibers are stretched?
A) The sarcomeres get longer.
B) The sarcomeres stay the same length.
C) The sarcomeres get shorter.

A

A

37
Q

Maximum tension indicates that the thick and thin filaments are set at optimal overlap to produce a maximum number of crossbridges, further stretching of the muscle will:
A) increase the amount of thick and thin filament overlap.
B) not change the amount of thick and thin filament overlap.
C) decrease the amount of thick and thin filament overlap.

A

C

38
Q

If the tension produced by a contracting muscle fiber depends upon the number of crossbridges between the thick and thin filaments, stretching the muscle beyond 28 mm:
A) decreases the amount of overlap and increases the amount of tension produced by a single contraction.
B) decreases the amount of overlap and does not change the amount of tension produced by a single contraction.
C) decreases the amount of overlap and decreases the amount of tension produced by a single contraction.

A

C

39
Q 
In the intact frog, muscles are held close to their resting length so that maximum tension can be achieved. Excessive shortening and lengthening of the muscle is prevented by:
	A)	tendons.
	B)	ligaments.
	C)	motor neurons.
	D)	bones and joints.
A

D

40
Q

If the amount of tension produced by the muscle depends upon the number of crossbridges, according to your data did the number of crossbridges:
A) decrease as the muscle was lengthened to about 28 mm?
B) remain constant as the muscle was lengthened to about 28 mm?
C) increase as the muscle was lengthened to about 28 mm?

A

C

Electrophysiology (3 decks)

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