CHAPTER 48

Which of the following statements about the transmission across a typical chemical synapse is true? (eText Concept 48.4)

The binding of neurotransmitter molecules to receptors on the postsynaptic cell membrane results in changes to the behavior of the postsynaptic cell.

Which of the following is a mechanism by which neurotransmitters can be rapidly cleared from the synaptic cleft? (eText Concept 48.4)

The neurotransmitters are actively transported back into the presynaptic cells to be repackaged into synaptic vesicles. The neurotransmitters are transferred to glia to be metabolized. Neurotransmitters are removed by simple diffusion. Neurotransmitters are removed by enzymatic hydrolysis of the neurotransmitter.

An action potential is __________. (eText Concept 48.3)

a traveling wave of depolarization in the neuron membrane

The interplay of multiple excitatory and inhibitory inputs most affects what part of a neuron? (eText Concept 48.4)

axon hillock

What are ganglia? (eText Overview)

clusters of nerve cell bodies

Blocking potassium ion channels in a mammalian cell membrane would __________. (eText Concept 48.2)

decrease the magnitude of the membrane potential

The part of a neuron that carries nerve impulses toward the cell body is called a(n) __________. (eText Concept 48.1)

dendrite

Action potentials are generated along a neuron because __________. (eText Concept 48.3)

depolarization of the membrane at one point causes an increase of permeability to sodium at the next point

Which of the following correctly pairs up a type of synapse and its characteristic? (eText Concept 48.4)

electrical synapse ... gap junctions

Which of the following is a natural pain reliever? (eText Concept 48.4)

endorphins

The sodium-potassium pump __________. (eText Concept 48.2)

expels sodium from the cell

Cells that provide metabolic and structural support to the neurons are called __________. (eText Concept 48.1)

glia

What is an increase in the magnitude of the membrane potential called? (eText Concept 48.3)

hyperpolarization

A drug that causes potassium to leak out of a neuron, increasing the positive charge on the outside, would __________. (eText Concept 48.3)

inhibit transmission of nerve signals by the neuron

Which of the following is specifically a part or a function of the central nervous system? (eText Concept 48.1)

integration

Schwann cells make up the __________. (eText Concept 48.3)

myelin sheath in axons of the PNS (peripheral nervous system)

Saltatory conduction means that the membrane potential changes __________. (eText Concept 48.3)

only at the nodes of Ranvier

Threshold is of great significance in the physiology of neurons. What happens if threshold is NOT reached? (eText Concept 48.3)

positive-feedback depolarization will not occur

In descriptions of synapse organization, which type of cell is the transmitting neuron and which type of neuron, muscle, or gland cell receives the signal? (eText Concept 48.1)

presynaptic ... postsynaptic

In humans, making more serotonin available to brain cells typically __________. (eText Concept 48.4)

produces an effect on mood

If your fingers touch a hot stove and you suddenly pull back, you have experienced a reflex. What is the correct order of the information processing in this reflex? (eText Concept 48.1)

sensory input, integration, motor output

A neuron that transmits an impulse to the central nervous system after the neuron is stimulated by the environment is called a(n) __________. (eText Concept 48.1)

sensory neuron

Neurons communicate by __________. (eText Overview)

short-distance chemical signals and long-distance electrical signals

The period in which an axon membrane CANNOT generate an action potential is called __________. (eText Concept 48.3)

the refractory period

Which of the following statements is correct? (eText Concept 48.1) 1

A neuron only has a single axon.

Acetylcholinesterase is the enzyme that degrades acetylcholine. What effect on nerve transmission would occur following the administration of a chemical that inhibited acetylcholinesterase? (eText Concept 48.4)

Continuous excitatory postsynaptic potentials would occur in the postsynaptic neuron.

Which of the following neurotransmitters typically has inhibitory effects? (eText Concept 48.4)

GABA (gamma-aminobutyric acid)

Which of the following statements about the resting potential is true? (eText Concept 48.2)

Inside the cell, the concentration of potassium is much higher than the concentration of sodium.

Which of the following statements is true? (eText Concept 48.2) 3

Ion channels are selectively permeable, permitting only certain ions to pass.