Chapter 12 Practice Quiz

Question 1

If a sodium channel in the plasma membrane of a neuron open, the [Na+] will move

Answer 1

inside the cell

Question 2

Impulses that are going toward the CNS are called __________ and impulses going away from the CNS are called __________.

Answer 2

Afferent, efferent

Question 3

__________ is the term used to describe the movement of potassium ions to the outside of a neuron, and __________ is the term used to describe excess potassium ions moving to the outside of a neuron.

Answer 3

Repolarization, hyperpolarization

Question 4

The smooth muscles and glands are controlled by the __________________________ nervous system.

Answer 4

.
autonomic nervous system

Question 5

During repolarization, the sodium channels are closed and inactivated. How does this affect a neuron?

Answer 5

The neuron cannot respond to new stimuli

Question 6

The all-or-none principle states that

Answer 6

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

Question 7

The myelin sheath that covers many Central nervous system axons is formed by

Answer 7

oligodendrocytes

Question 8

Mechanically –gated ion channels are a class of transmembrane ion channels which open their pores in response to mechanical deformation of a neuron’s plasma membrane.

Answer 8

True

Question 9

When the sodium potassium pump breaks down a molecule of ATP, ______ K+ ions are moved into the cell and ______ Na+ are moved out of the cell.

Answer 9

2/3

Question 10

Answer 10

voltage-gated potassium channels are open and potassium leaves the cell making cell more negative inside.

Question 11

The junction between two communicating neurons is called the

Answer 11

synapse

Question 12

The skeletal muscles are controlled by the _______________________________nervous system

Answer 12

somatic motor nervous system

Question 13

The 2 divisions of the somatic nervous system are the sympathetic division and the parasympathetic division.

Answer 13

False

Question 14

An example of an effector

Answer 14

Skeletal Muscle
Smooth muscle
Glands

Question 15

Extracellular potassium levels are ____________________ intracellular potassium levels

Answer 15

lower than

Question 16

The axons of some neurons in the CNS are protected by glial cells that form a myelin sheath around the axons. These glial cells are called

Answer 16

Oligodendrocytes

Question 17

Depolarization is the term used to describe the movement of __________ ions to the inside of a neuron while repolarization is the term used to describe the movement of __________ ions to the outside of neuron

Answer 17

Sodium/ potassium

Question 18

When the action potential reaches the terminal end of an axon

Answer 18

vesicles of neurotransmitter fuse with the outer membrane and release the neurotransmitter into synaptic cleft

Question 19

Answer 19

During this phase voltage -gated sodium channels are open and sodium enters the cell making cell more positive inside

Question 20

Na+ inside a neuron is normally ________________________ [Na+] outside a neuron.

Answer 20

lower than

Question 21

Answer 21

it is depolarization phase of action potential

Question 22

Answer 22

It is repolarization phase of action potential

Question 23

Chemically –gated (ligand) channels are a group of transmembrane ion channel proteins which open in response to the binding of a chemical messenger ( a ligand), such as a neurotransmitter.

Answer 23

True

Question 24

Which of the following statements is true?

Answer 24

Neurolemmocytes (Schwann cells) form a myelin sheath around axons in the peripheral nervous system, and oligodendrocytes form a myelin sheath around axons in the central nervous system

Question 25

Neurons consist of a cell body, axons, and _________________________, which receive information.

Answer 25

dendrites

Question 26

Voltage-gated ion channels are found on

Answer 26

axon hillock, unmyelinated axons, and nodes of Ranvier on myelinated axons

Question 27

A neuron has a polarized membrane, which means it is relatively positive on the outside of the membrane and negative on the inside. Which of the following creates this opposite charge characteristic of a neuron's membrane?

Answer 27

Na+/K+exchange pump transfers 3 sodium outside and brings 2 potassium inside the cell Higher protein concentration inside the cell K+ diffuses outward through leak channels

Question 28

If a small amount of chloride Cl- entered the soma of the motor neuron through chemically gated channels, which of the following would occur?

Answer 28

Hyperpolarization will occur and the neuron would less likely to fire action potential

Question 29

Which part of the neuron is involved in sending an impulse to the synaptic area?

Answer 29

axon

Question 30

What is refractory period?

Answer 30

refractory period is a short period during action potential when the cell cannot respond to a new stimulus

Question 31

if sodium - potassium exchange pumps in the plasma membrane fail to function due to lack of ATP , all of the following occur, except

Answer 31

the intracellular concentration of potassium ions will increase

Question 32

The brain and spinal cord have noticeable areas of gray and white. Which of the following constitutes the white matter?

Answer 32

myelinated axons

Question 33

Which of the following is NOT a function of glial cells?

Answer 33

Sending action potentials to effector tissues