QUESTION 1 RynR select all that apply is a voltagegated Ca2

QUESTION 1

Ryn-R [select all that apply]

is a voltage-gated Ca²⁺ channel

b.is a mechanically-gated Ca²⁺ channel

is in the SR membrane

is in the cytoplasmic membrane

directly resoponds to cellular depolarization

1 points   

QUESTION 2

DHP-R [select all that apply]

is a mechanically-gated Ca²⁺ channel

is a V-gated Ca²⁺ channel

is in the SR membrane

is in the cytoplasmic membrane

directly responds to cellular depolarization

1 points   

QUESTION 3

Nicotinic receptors [select all that apply]

interacts with ACh

degrade ACh

allow Na⁺ ions to flow through when active

allow K⁺ ions to flow through when active

are part of the NMJ in somatic motor pathways

are part of ganglions in autonomic pathways

1 points   

QUESTION 4

Which of these statements about sarcomere shortening is FALSE?

a.The thick and thin filaments slide past each other.

b.The length of the A band remains constant.

c.The length of the I band remains constant.

d.The length of the H zone decreases.

e.The distance between the Z disks decreases.

1 points   

QUESTION 5

Select all TRUE statements about the power stroke cycle. [select all that apply]

a.Myosin releases actin when ATP binds.

b.Myosin binds actin when ATP binds.

c.The hydrolysis of ATP to ADP + P_i initiates the power stroke of the myosin head.

d.The hydrolysis of ATP to ADP + P_i  \"cocks\" the myosin head and bind actin.

e.The release of P_i initiates the power stroke of the myosin head

f.The release of  P_i leaves the myosin head in the rigor state.

g.The release of ADP leaves the myosin head in the rigor state.

Myosin releases actin when ADP is released.

1 points   

QUESTION 6

Match the characteristic to either \"slow-twitch oxidative muscle\" or \"fast-twitch glycolytic muscle\".

appears white

appears red

has a long contraction duration

is easily fatigued

low capillary density

has many mitochondria

fast-twitch glycolytic muscle

slow-twitch oxidative muscle

1 points   

QUESTION 7

The maximal force will be developed by a muscle at its _______________.

shortest length

b.intermediate length

c.maximal length

it does not matter what length the muscle is.

1 points   

QUESTION 8

An isotonic contraction occurs when [select all that apply]

the muscle contracts but does not shorten or move the load

the muscle contracts, is able to shorten, and move the load

c. the muscle contracts and is able to shorten but does not move the load

the muscle contracts and is able to move the load but the muscle does not shorten

the muscle contracts and the sarcomeres shorten

1 points   

QUESTION 9

An isometric contraction occurs when [select all that apply]

the muscle contracts but does not shorten or move the load

the muscle contracts, is able to shorten, and move the load

c.the muscle contracts and is able to shorten but does not move the load

the muscle contracts and is able to move the load but the muscle does not shorten

the muscle contracts and the sarcomeres shorten

	a.	is a voltage-gated Ca2+ channel
		b.is a mechanically-gated Ca2+ channel
	c.	is in the SR membrane
d.		is in the cytoplasmic membrane
e.		directly resoponds to cellular depolarization

Solution

Q.1 c.   is in the SR membrane

Ryanodine receptors mediate the release of calcium ions from the sarcoplasmic reticulum

Q2. b.   is a V-gated Ca2+ channe

The dihydropyridine receptor (DHPR), normally a voltage-dependent calcium channel, functions in skeletal muscle

Q3.

a. interacts with ACh

c. allow Na+ ions to flow through when active

d.   allow K+ ions to flow through when active

e.   are part of the NMJ in somatic motor pathways

respond to the neurotransmitter acetylcholine.It is a non-selective cation channel, permeable to Na+ and K+,