Chapter 12 Learnsmart

Which term refers to the microscopic physical gap between the presynaptic and postsynaptic neurons at a chemical synapse?

synaptic cleft

What is the approximate ratio of glial cells to neurons?

10:1

Which best describes an electrical potential?

A form of potential energy that can produce current

Which best describes signal conduction in unmyelinated axons?

A wave of depolarization opens more voltage-gated channels immediately distal to the action potential.

Choose all of the following statements that are true about signal conduction along unmyelinated fibers.

A zone of depolarization excites voltage-gated channels immediately distal to the action potential. Unmyelinated fibers have voltage-gated channels along their entire length.

Which fundamental physiological property of neurons allows them to send signals quickly over long distances?

Conductivity

Choose all the factors that influence the speed of nerve signal conduction.

Diameter of axon Presence of myelin

Choose all that would cause postsynaptic stimulation to end.

Diffusion of neurotransmitter from the synaptic cleft into extracellular fluid Enzymatic degradation of neurotransmitter in the synaptic cleft Cessation of signals in the presynaptic nerve fiber Reuptake of neurotransmitter into the presynaptic knob

List the fundamental physiological properties of neurons.

Excitability, conductivity, secretion

Choose all that are characteristics of local potentials.

Graded Decremental

In a synapse, where are synaptic vesicles located?

In the axon terminal

Which correctly describe axonal transport?

It is bidirectional (retrograde and anterograde transport). It involves transport of proteins within the axon (i.e. synaptic knob enzymes or proteins that maintain the axolemma).

Which of the following contributes to the development of the resting membrane potential in neurons?

K+ is more concentrated in the ICF than in the ECF.

Which two organ systems are primarily responsible for coordinating the other bodily systems so as to maintain homeostasis?

Nervous system Endocrine system

Choose all that are names for the cell body of a neuron.

Neurosoma Soma

Stimulation of the postsynaptic neuron will end when nerve signals stop arriving at the presynaptic axon terminal or when which of the following occurs?

Neurotransmitter is removed from postsynaptic receptors.

Choose all that are properties of action potentials.

Self-propagating Nondecremental (signal maintains amplitude) All or none

Choose all statements that are true regarding postsynaptic potentials?

They are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. They include EPSPs and IPSPs. They are caused by neurotransmitters.

Choose all the statements that characterize neurotransmitters?

They are released in response to stimulation. They bind to receptors and alter the physiology of the postsynaptic cell. They are synthesized by presynaptic neurons.

Choose all that are characteristics of neural pools.

They may be concerned with a particular body function. They consist of complex patterns of interneurons.

Which term refers to the passage of proteins, organelles and other materials along an axon?

axonal transport

The nervous system must interpret quantitative and qualitative information about its environment, thus it converts information to a meaningful pattern of action potentials. This process is called neural

coding

In the CNS; line cavities of the brain and spinal cord; secrete and circulate CSF

epondymal cells

True or false: Damaged nerve fibers in the CNS regenerate very fast whereas damaged nerve fibers in the PNS never regenerate.

false

True or false: Electrical synapses are able to integrate information and make decisions more rapidly than chemical signals.

false

True or false: The more synapses a neuron has, the lesser its information-processing capability.

false

The myelin sheath is a spiral layer of ______ around a nerve fiber.

insulation

The myelin sheath is composed mostly of which of the following?

lipids

Which term refers to decremental changes in electrical potential along a dendrite or the soma?

local potentials

In the CNS; phagocytize microorganisms, foreign matter, and dead nervous tissue

microglia

Which term describes the ability of neurons to process information, store and recall it, and make decisions?

neural integration

Sensory, association and motor are the three classes of what?

neurons

At a synapse, the neuron that responds to the neurotransmitter is the ______ neuron.

postsynaptic

In a chemical synapse, synaptic vesicles full of neurotransmitter are docked at release sites on the membrane of the presynaptic neuron, while neurotransmitter receptors are found on the membrane of the ... neuron.

postsynaptic

Neural integration is based on the combining together of which of the following?

postsynaptic potentials

Which ion has the greatest influence on the resting membrane potential of most neurons?

potassium

An electrical potential is a form of what type of energy?

potential energy

At a synapse, the neuron that releases neurotransmitter is the ______ neuron.

presynaptic

Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?

refractory period

The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the ______ refractory period.

relative

In the PNS; surround somas of neurons in ganglia, provide electrical insulation, and regulate the chemical environment of neurons

satellite cells

In the PNS; form neurilemma around all PNS fibers and myelin around most of them; aid in regeneration of damaged nerve fibers.

schwann cells

Which type of glial cell aids in regeneration of damaged peripheral nerve fibers by forming a regeneration tube to help reestablish the former connection?

schwann cells

Which type of memory allows you to remember things from up to a few hours ago?

short term

There are two ways in which EPSPs can add up to produce enough activity to make a postsynaptic cell fire. They are temporal and spatial

summation

There are two ways in which EPSPs can add up to produce enough activity to make a postsynaptic cell fire. They are temporal and spatial .

summation

True or false: Unmyelinated nerve fibers (axons) in the PNS are enveloped in Schwann cells.

true

Looking up a new phone number and then dialing it from memory utilizes which type of memory?

working memory

A cholinergic synapse uses which of the following as its neurotransmitter?

Acetylcholine

Select all that are categories of neurotransmitters based on chemical composition

Acetylcholine Neuropeptides Monoamines Amino acids

Which term refers to a synapse that releases acetylcholine from the presynaptic axon terminal?

cholinergic

Two organ systems are dedicated to internal coordination, communication between the other systems, and maintaining the overall homeostasis of the body. They are the .... system, which communicates by means of hormones, and the ... system which sends quick electrical and chemical messages from cell to cell.

endocrine nervous

Which is true about a neuron with a large diameter, myelinated axon as compared to a neuron with a small diameter, unmyelinated axon?

Signal conduction will be faster

An axon lacking a myelin sheath is said to be what?

Unmyelinated

In electrical synapses, electrical signals move quickly from cell to cell through which of the following?

gap junctions

______ cells protect the neurons and help them function.

glial

Which neuroglial cell is found in the peripheral nervous system?

satellite cells

What is the role of neural pools in the CNS?

to process information

True or false: Action potentials occur only where there are voltage-gated ion channels.

true

Choose all the ways neuromodulators alter synaptic transmission.

Altering the breakdown and/or reuptake of neurotransmitter Adjusting the sensitivity of postsynaptic neurons to neurotransmitters Increasing the release of neurotransmitters by presynaptic neurons

Choose all that are usually found inside the cell body (or soma) of a mature neuron.

Mitochondria Rough endoplasmic reticulum Nucleus

Choose the three functional classes of neurons.

Motor neurons Interneurons Sensory neurons

Which alter synaptic transmission by adjusting the sensitivity of postsynaptic neurons to neurotransmitters or by affecting the breakdown and/or removal of a neurotransmitter?

Neuromodulators