Chapter 12 - Module

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. -The signal conduction in unmyelinated fibers is saltatory -Unmyelinated fibers have voltage-gated channels along their entire length.

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

Choose all the ways neuromodulators alter synaptic transmission. -Altering the breakdown and/or reuptake of neurotransmitter -Promoting myelination by oligodendrocytes or Schwann cells -Adjusting the sensitivity of postsynaptic neurons to neurotransmitters -Increasing the release of neurotransmitters by presynaptic neurons

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

Which types of glial cells are found in the central nervous system? -Astrocytes -Ependymal cells -Oligodendrocytes -Microglia -Schwann cells -Satellite cells

-Astrocytes -Ependymal cells -Oligodendrocytes -Microglia

Choose all that would cause postsynaptic stimulation to end. -Enzymatic degradation of neurotransmitter in the synaptic cleft -Diffusion of neurotransmitter from the synaptic cleft into extracellular fluid -Reuptake of neurotransmitter into the presynaptic knob -Cessation of signals in the presynaptic nerve fiber -Addition of receptors onto presynaptic membrane

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

Choose all that are properties of action potentials. -Self-propagating -Graded -All or none -Nondecremental (signal maintains amplitude)

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

Long-term potentiation may be involved in long-term memory. Choose all of the following that are molecular changes that occur in long-term potentiation. -The release of nitric oxide which triggers more glutamate release -Entrance of calcium into the dendrite -A decrease in the number of NMDA receptors. -Binding of glutamate to NMDA receptors

-The release of nitric oxide which triggers more glutamate release -Entrance of calcium into the dendrite -Binding of glutamate to NMDA receptors

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 are caused by neurotransmitters. -They depend on the myelination of nerve axons. -They include EPSPs and IPSPs.

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

Choose all the statements that characterize neurotransmitters? -They are synthesized by presynaptic neurons. -They are released in response to stimulation. -They bind to receptors and alter the physiology of the postsynaptic cell. -They stimulate the opening of voltage-regulated gates at the postsynaptic membrane -They are found in dendrites of postsynaptic neurons

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

Choose all that are characteristics of neural pools. -They may be concerned with a particular body function. -They consist of sensory neurons that synapse directly onto motor neurons. -They classify neurons based on shape. -They consist of complex patterns of interneurons.

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

What is the approximate ratio of glial cells to neurons?

10:1

Which best describes signal conduction in unmyelinated axons?

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

Select all that are categories of neurotransmitters based on chemical composition. -Acetylcholine -Amino acids -Sterols -Neuropeptides -Monoamines -Glycoproteins

Acetylcholine Amino acids Neuropeptides Monoamines

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

Cholinergic

Choose all the factors that influence the speed of nerve signal conduction. -size of soma -Diameter of axon -type of neuron (multipolar vs. unipolar) -Presence of myelin

Diameter of axon Presence of myelin

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

False

ependymal cells

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

microglia

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

Schwann cells

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

satellite cells

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

Which correctly describe axonal transport? -It involves transport of proteins within the axon (i.e. synaptic knob enzymes or proteins that maintain the axolemma). -It is bidirectional (retrograde and anterograde transport). -it is a type of transport that occurs only in anaxonic neurons

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

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.

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 form postsynaptic receptors

Choose all that are usually found inside the cell body (or soma) of a mature neuron. -rough endoplasmic reticulum -synaptic vesicles -mitochondria -nucleus -centrioles

Rough ER, mitochondria, and nucleus

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

T or F: Action potentials occur only where there are voltage-gated ion channels.

True

Which best describes an electrical potential?

a form of potential energy that can produce current

The refractory period in which no stimulus of any strength will trigger a new action potential is the ______ refractory period.

absolute

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

acetylcholine

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

Choose all that are types of long-term memory? -immediate -declarative -working -procedural

declarative and procedural

The processes of a neuron that usually receive signals from other neurons are called

dendrites

The processes that branch from the somas of most neurons are called __

dendrites

List the fundamental physiological properties of neurons.

excitability, conductivity, secretion

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

false

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

false

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

Choose all that are characteristics of local potentials. -graded -decremental -self-propagating -all-or-none

graded and decremental

Short-term memory allows you to remember things for up to how long?

hours

In a synapse, where are synaptic vesicles located?

in the axon terminal

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

Which type of memory can store the most information?

long-term

Declarative and procedural memory are two types of what?

long-term memory

Which may be the basis for learning and long-term memory at the neuronal level?

long-term potentiation

Which two organ systems are primarily responsible for coordinating the other bodily systems so as to maintain homeostasis? -nervous -cardiovascular -endocrine -immune

nervous and endocrine

This picture illustrates that when a stimulus strength (weight) and stretch increase at a sensory fiber, the firing frequency of the neurons increase. Which term refers to the conversion of stimulus information into a meaningful pattern of action potentials?

neural coding

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

neural integration

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

Sensory, inter, and motor are the three classes of Blank__

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 release of a neurotransmitter is an example of which physiological property exhibited by a neuron?

secretion

Afferent neurons are what type of neurons?

sensory

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

Choose all that are names for the cell body of a neuron. -soma -astrocyte -ganglion -neurosoma -inclusion

soma and neurosoma

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

This picture illustrates a phenomenon that occurs in the trigger zone when multiple postsynaptic potentials combine their effects on a cell to produce a response. What is it called?

summation

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

synaptic cleft

What is the role of neural pools in the CNS?

to process information

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

true

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

unmyelinated

How long can long-term memory last?

up to a lifetime

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

working memory