Block 3_Chapter 12

Question 1

Voltage-gated sodium channels have both an activation gate and a ________ gate.

Answer 1

inactivation

Question 2

The site of intercellular communication between neurons is the

Answer 2

synapse

Question 3

The effect that a neurotransmitter has on the postsynaptic membrane depends on

Answer 3

a. the frequency of neurotransmitter release.
b. the nature of the neurotransmitter.
c. the characteristics of the receptors.
d. the quantity of neurotransmitters released.

Question 4

The ________ nervous system controls the skeletal muscles.

Answer 4

somatic

Question 5

Type ________ fibers have the largest diameter axons.

Answer 5

A

Question 6

Voltage-gated channels are present

Answer 6

in the membrane that covers axons

Question 7

Functions of astrocytes include all of the following,

Answer 7

• responding to neural tissue damage
• guiding neuron development
• forming a 3D framework for the CNS
• maintaining the blood-brain barrier

Question 8

Sensory neurons of the PNS are

Answer 8

unipolar

Question 9

Which of the following are a type of glial cell found in the peripheral nervous system?

Answer 9

satellite cells

Question 10

________ neurons form the afferent division of the PNS.

Answer 10

sensory

Question 11

In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by

Answer 11

forming a cellular cord that directs axonal regrowth

Question 12

The neurilemma of axons in the peripheral nervous system is formed by

Answer 12

Schwann Cells

Question 13

The part of the peripheral nervous system that carries sensory information to the CNS is designated

Answer 13

afferent

Question 14

Ion channels that are always open are called ________ channels.

Answer 14

leak

Question 15

________ neurons are small and have no anatomical features that distinguish dendrites from axons.

Answer 15

axonic

Question 16

The site in the neuron where the EPSPs and the IPSPs are integrated is the:

Answer 16

axon hillock

Question 17

At the normal resting potential of a typical neuron, its Na-K ion exchange pump transports

Answer 17

3 intracellular sodium ions for 2 extracellular potassium ions.

Question 18

Which type of synapse is most common in the nervous system?

Answer 18

chemical

Question 19

Which point of the graph shows when potassium ion outflow exceeds sodium ion inflow?

Answer 19

hyperpolarization

Question 20

The function of the astrocytes in the CNS includes which of the following?

Answer 20

• adjusting the composition of the interstitial fluid
• guiding neuron development
• maintaining the BBB
• repairing damaged neural tissue

Question 21

If the chemically gated sodium channels in the postsynaptic membrane were completely blocked,

Answer 21

synaptic transmission would fail

Question 22

The ion that triggers the release of acetylcholine into the synaptic cleft is

Answer 22

Calcium

Question 23

________ open or close in response to binding specific molecules.

Answer 23

chemically gated channels

Question 24

The efferent division of the peripheral nervous system innervates:

Answer 24

• skeletal muscle cells
• smooth muscle cells
• heart muscle cells
• glandular cells

Question 25

________ line the brain ventricles and spinal canal.

Answer 25

ependymal cells

Question 26

Which of the following types of nerve fiber possesses the fastest speed of impulse propagation?

Answer 26

Type A

Question 27

Branches that may occur along an axon are called

Answer 27

collaterals

Question 28

The axon is connected to the soma at the

Answer 28

axon hillock

Question 29

Sensory information from skeletal muscle travels over _____ fibers.

Answer 29

Type A

Question 30

Opening of sodium channels in the axon membrane causes

Answer 30

Depolarization and increased positive charge inside the membrane

Question 31

EPSPs (excitatory postsynaptic potentials) occur when

Answer 31

Extra sodium ions enter a cell

Question 32

Which of the following interactions between electrical and chemical gradients does not lead to the establishment of a neuron's resting potential?

Answer 32

Electrical forces push sodium ions out of the cell

Question 33

The same ________ can have different effects depending on the properties of the ________.

Answer 33

neurotransmitter; receptorr

Question 34

In the process of continuous action potential propagation,

Answer 34

- the action potential is triggered by graded depolarization of the initial segment - at threshold, sodium channels begin to open rapidly - local currents depolarize the region just adjacent to the active zone

Question 35

Which area of the graph occurs when there is a sudden in rush of sodium ions?

Answer 35

during depolarization, and the inactivation Na+ gates and the activation gates are both open

Question 36

Neurotransmitter for release is stored in synaptic

Answer 36

vesicles

Question 37

When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs?

Answer 37

temporal summation

Question 38

IPSPs (inhibitory postsynaptic potentials)

Answer 38

are local hyperpolarizations

Question 39

After acetylcholinesterase acts, the synaptic knob

Answer 39

reabsorbs the choline

Question 40

Which of the following does influence the time necessary for a nerve impulse to be transmitted?

Answer 40

- presence or absence of a myelin sheath - presence or absence of nodes - length of axon - diameter of the axon

Question 41

Deteriorating changes in the distal segment of an axon as a result of a break between it and the soma is called ________ degeneration.

Answer 41

Wallerian

Question 42

Adrenergic synapses release the neurotransmitter

Answer 42

NE

Question 43

Axons terminate in a series of fine extensions known as

Answer 43

telodendria

Question 44

When is the neuron in the refractory period?

Answer 44

Right after the absolute refractory period. About 2/3 of the way during repolarization

Question 45

The all-or-none principle states that

Answer 45

all stimuli great enough to bring the membrane to threshold will produce identical action potentials

Question 46

Which of the following are properties of cerebrospinal fluid?

Answer 46

- Surrounds the brain and spinal cord - fills the brain ventricles - transports nutrients - circulates continuously

Question 47

Ions can move across the plasma membrane in which of the following ways?

Answer 47

- through voltage-gated channels as in the action potential - through passive or leak channels - by ATP-dependant ion pumps like the sodium-potassium pump exchange pump - through chemically-gated channels as in neuromuscular transmission

Question 48

Which of the following is the most important excitatory amino acid neurotransmitter in the brain?

Answer 48

glutamate