RynR select all that apply is a voltagegated Ca2 channel bis

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

1)

a. is a voltage-gated Ca2+ channel (as it releases calcium ions)

c. is in the SR membrane (Present in sarcoplasmic reticulum)

e. directly responds to cellular depolarization (depolarization induced by calcium ions)

2)

b. is a V-gated Ca2+ channel (as it releases calcium ions)

c. is in the SR membrane (Present in sarcoplasmic reticulum)

e. directly responds to cellular depolarization (depolarization induced by calcium ions)

3)

a. interacts with Ach

c. allow Na+ ions to flow through when active (Its a non selective cation channel Permeable to positive ions like sodium)

d. allow K+ ions to flow through when active (Its a non selective cation channel Permeable to positive ions like Potassium)

e. are part of the NMJ in somatic motor pathways (In Neuromuscular junction, nicotinic receptors are present on alpha motor neurons.)

4)

c. The length of the I band remains constant. (I band length gets shorten during contraction of the muscle)

5)

a. Myosin releases actin when ATP binds. ( ATP acts as a energy source)

c. The hydrolysis of ATP to ADP + Pi initiates the power stroke of the myosin head. (ATP acts as a energy source, upon hydrolysis energy get released which is used to shape of the myosin head)

f. The release of  P_i leaves the myosin head in the rigor state. (Upon release of Pi myosin comes back to low energy form and remains attached with actin known as rigor state)

g. The release of ADP leaves the myosin head in the rigor state. (Upon release of ADP myosin comes back to low energy form and remains attached with actin known as rigor state)

6)

1. A fast-twitch glycolytic muscle appears white

2. B slow-twitch oxidative muscle appears red

3. B slow-twitch oxidative muscle : has a long contraction duration

4. A. fast-twitch glycolytic muscle is easily fatigued

5. A. fast-twitch glycolytic has    Low capillary density

6.B. slow-twitch oxidative muscle has many mitochondria  

7)

The maximal force will be developed by a muscle at its:

b. intermediate length ( at ideal or resting leangth)

8) An isotonic contraction occurs when

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

( It occurs during concentric contraction, muscle length shortens without addition of load)

9) An isometric contraction occurs when

a. the muscle contracts but does not shorten or move the load

(Length of the muscle remains same without addition of load)