Chapter 12 Practice Quiz Flashcards

1
Q

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

A

inside the cell

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2
Q

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

A

Afferent, efferent

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3
Q

__________ 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.

A

Repolarization, hyperpolarization

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4
Q

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

A

.
autonomic nervous system

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5
Q

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

A

The neuron cannot respond to new stimuli

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6
Q

The all-or-none principle states that

A

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

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7
Q

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

A

oligodendrocytes

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8
Q

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.

A

True

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9
Q

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.

A

2/3

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10
Q
A

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

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11
Q

The junction between two communicating neurons is called the

A

synapse

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12
Q

The skeletal muscles are controlled by the _______________________________nervous system

A

somatic motor nervous system

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13
Q

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

A

False

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14
Q

An example of an effector

A

Skeletal Muscle
Smooth muscle
Glands

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15
Q

Extracellular potassium levels are ____________________ intracellular potassium levels

A

lower than

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16
Q

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

A

Oligodendrocytes

17
Q

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

A

Sodium/ potassium

18
Q

When the action potential reaches the terminal end of an axon

A

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

19
Q
A

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

20
Q

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

A

lower than

21
Q
A

it is depolarization phase of action potential

22
Q
A

It is repolarization phase of action potential

23
Q

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.

A

True

24
Q

Which of the following statements is true?

A

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

25
Q

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

A

dendrites

26
Q

Voltage-gated ion channels are found on

A

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

27
Q

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?

A

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

28
Q

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

A

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

29
Q

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

A

axon

30
Q

What is refractory period?

A

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

31
Q

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

A

the intracellular concentration of potassium ions will increase

32
Q

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

A

myelinated axons

33
Q

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

A

Sending action potentials to effector tissues