Exam #3 Multiple Choice

Question 1

Which of the following connective tissue sheaths surrounds an individual skeletal muscle cell?

Answer 1

endomysium

Question 2

The downward regulation of protein synthesis in a muscle cell is controlled by

Answer 2

nuclei

Question 3

The range of sarcomere length that is the strongest in maximum tetanic tension is determined by the fact that:

Answer 3

the most actin-myosin crossbridge connections are possible

Question 4

The terminal cisternae is part of

Answer 4

sarcoplasmic reticulum

Question 5

Which of the following listings of muscle tissue categories is listed from largest to smallest?

Answer 5

fascicle, fiber, myofibril myofilament, sarcomere

Question 6

Calcium ions, when released from the sarcoplasmic reticulum, interact with ________ on the actin filaments

Answer 6

troponin C

Question 7

The specialized network of membranes tubules that stores calcium ions in a muscle fiber is the

Answer 7

sarcoplasmic reticulum

Question 8

“Rigor” means

Answer 8

No actin-myosin dissociation due to lack of ATP

Question 9

Hydrolysis of ATP to ADP + Pi seems to:

Answer 9

Cause conformational change of the myosin head (“cocked and uncocked” position)

Question 10

Which is NOT true about titin?

Answer 10

Is a contractile protein

Question 11

T-Tubules are necessary to…

Answer 11

myofibrillar activation

Question 12

The role of acetylcholinesterase is to:

Answer 12

destroy ACh a brief period after its release by the axonal endings

Question 13

Direct-acting neurotransmitters:

Answer 13

open ion channels to provoke rapid response

Question 14

An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is:

Answer 14

acetylcholine

Question 15

The period after an initial stimulus when a neuron is not sensitive to another stimulus is the:

Answer 15

refractory period

Question 16

Which of the following is not a structural feature of a neuron?

Answer 16

synaptic cleft

Question 17

The part of a neuron that conducts impulses away from its cell body is called a(n):

Answer 17

axon

Question 18

The point at which an impulse from a nerve cell is communicated to another cell is the:

Answer 18

synapse

Question 19

The role of acetylcholinersterase is to:

Answer 19

destry ACh a brief period after its release by the axonal endings

Question 20

The substance released at axonal endings to propagate a nervous impulse is called:

Answer 20

neurotransmitter

Question 21

The substance released at axonal endings to propagate a nervous impulse is called:

Answer 21

neurotransmitter

Question 22

Salsatory conduction is made possible by:

Answer 22

the myelin sheath

Question 23

The sodium potassium pump:

Answer 23

pumps three sodium ions outside the cell and two potassium ions inside

Question 24

An action potential:

Answer 24

is essential for impulse propagation

Question 25

Select the correct statement about synapses

Answer 25

THe synaptic cleft prevents an impulse from being transmitter directly from one neuron to another

Question 26

Select the correct statement about synapses

Answer 26

The synaptic cleft prevents an impulse from being transmitter directly from one neuron to another

Question 27

Immediately after an action potential has peaked, which cellular gates open?

Answer 27

potassium

Question 28

An inhibitory postsynaptic potential (IPSP) is associated with:

Answer 28

hyperpolarization

Question 29

A following nerve impulse cannot be propagated until:

Answer 29

the membrane potential has been reestablished

Question 30

In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differs from the external environment? The interior is:

Answer 30

negatively charged and contains less sodium

Question 31

What is the physiological mechanism of Botox, making it useful for “clinical” application?

Answer 31

Enters the presynaptic nerve terminal, blocking the normal release of ACh into the synaptic cleft which blocks muscle contraction