Nervous tissue h.w

The autonomic nervous system is subdivided into the ______ division which tends to arouse the body for action and the ______ division which tends to have a calming effect.

sympathetic, parasympathetic

Which is most likely to be the threshold potential for a neuron?

-55

Which is most likely to be the resting membrane potential of a neuron?

-70 mV

Which numerical value is most likely to be the resting membrane potential of a neuron?

-70 mV

Select all that are categories of neurotransmitters based on chemical composition.

-Acetylcholine -Monoamines -Neuropeptides -Amino acids

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

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).

Which statements are true about signal conduction along myelinated fibers?

-There are few voltage-gated ion channels at the myelin-covered internodes and multiple channels at the nodes of Ranvier. -Action potentials occur only at the nodes of Ranvier. -Ions can be exchanged with the ECF only at the nodes of Ranvier.

Choose all the statements that characterize neurotransmitters?

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

Choose all that are characteristics of neural pools.

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

Choose all statements that are true regarding postsynaptic potentials?

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

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

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

Choose all the neurotransmitters that are classified as amino acids.

-glycine -glutamate -aspartate -y-aminobutyric acid (GABA)

The myelin sheath is composed mostly of

-lipids -phospholipids

converging circuit

-postsynaptic neuron receives nerve impulses from several different sources

trigger zone

-where action potential is generated -the junction between the axon hillock and the initial segment -play an important role in initiating a nerve signal

Which best describes an electrical potential?

A form of potential energy that can produce current

The neurotransmitters glutamate and GABA are examples of which of the following?

Amino acids

Which process of a neuron is specialized for rapid conduction of nerve signals to structures relatively far away from the neuron cell body?

Axon

Which term applies to the small swellings at the distal end of the axon of a neuron that contain synaptic vesicles?

Axon terminals

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

Axonal transport

Neurons that have one axon and one dendrite, such as olfactory cells, certain neurons of the retina, and sensory neurons of the inner ear, are classified as which of the following?

Bipolar

Tetanic stimulation at a synapse is due to accumulation of which of the following in the synaptic terminal?

Calcium

Memories lasting for a few hours, such as remembering what someone said to you earlier in the day may involve posttetanic potentiation. This occurs because of which of the following?

Calcium remains in the synaptic knob elevated and a later signal releases a large burst of neurotransmitter.

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

Cholinergic

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

Conductivity

The respiratory center of the brain receives input from other parts (i.e from receptors for blood chemistry in arteries and stretch receptors in the lungs) to set a pattern of breathing. This is an example of which type of circuit?

Converging

The circuit in which several input nerve fibers synapse with fewer postsynaptic neurons is what type of circuit?

Converging circuit

Which term refers to the flow of charged particles from one point to another?

Current

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

Dendrites

The soma of a neuron gives rise to branch-like processes called what? They are the primary sites for receiving signals from other neurons.

Dendrites

During which part of the action potential do most voltage-gated sodium channels open?

Depolarization

Which term refers to the upward change in membrane potential during an action potential?

Depolarization

A single motor neuron stimulating hundreds of skeletal muscle cells is an example of which type of circuit?

Diverging

Choose all that are the principal types of neural circuits.

Diverging circuit Reverberating circuit Converging circuit Parallel after-discharge circuit

Which term is used to describe motor neurons because they send signals away from the CNS and out to muscle and gland cells?

Efferent

Which glial cell produces and helps circulate cerebrospinal fluid?

Ependymal cells

found in the central nervous system

Ependymal cells Microglia Astrocytes Oligodendrocytes

Which neurotransmitter is a catecholamine?

Epinephrine

List the fundamental physiological properties of neurons.

Excitability, conductivity, secretion

True or false: All neurotransmitters have an excitatory effect.

False

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

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

Gap junctions

Nodes of Ranvier

Gaps in the myelin sheath to which voltage-gated sodium channels are confined.

______ cells protect the neurons and help them function.

Glial

Choose all that are characteristics of local potentials.

Graded Decremental

Which type of memory is important as you read (e.g. remembering the previous words in a sentence)?

Immediate

Between the nodes of Ranvier are myelin-covered segments of axon encircled by Schwann cells. Which term refers to these segments?

Internodes

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 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

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

Mitochondria Nucleus Rough endoplasmic reticulum

Neurons with numerous dendrites and a single axon are structurally classified as which of the following?

Multipolar

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

Nervous system Endocrine system

The pathway of neurons within a neural pool is called its what?

Neural circuit

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

Neurons

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.

Which term refers to the gaps between segments of myelin along an axon?

Nodes of Ranvier

Which glial cell insulates nerve fibers from extracellular fluids and speeds up signal conduction in the brain?

Oligodendrocyte

GABA has an inhibitory effect on postsynaptic neurons because it does which of the following?

Opens chloride channels

Taken together, the sensory and motor subdivisions make up which of the following?

Peripheral nervous system

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

Postsynaptic potentials

Memories lasting for a few hours, such as recalling an incident earlier in the day, may be due to which of the following?

Posttetanic potentiation

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

Potassium

Synapses in a certain pathway can be modified to allow signals to travel more easily across "trained" synapses. Which term refers to the process of making transmission easier?

Potentiation

factors that influence the speed of nerve signal conduction

Presence of myelin Diameter of axon

Choose all that are types of long-term memory?

Procedural Declarative

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

Secretion

Choose all that are properties of action potentials.

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

three functional classes of neurons.

Sensory neurons Interneurons Motor neurons

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

Short-term

Why is sodium more concentrated in the ECF than in the ICF of most neurons?

Sodium is actively pumped out of the cell by transporter proteins.

The sensory and motor divisions of the peripheral nervous system are further split into which two subdivisions?

Somatic and visceral

Which division inhibits digestion?

Sympathetic

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

Synaptic cleft

Which term refers to summation that results from a single synapse firing rapidly in sequence?

Temporal

When a single synapse generates EPSPs so quickly that each is generated before the previous one fades, what is this process called?

Temporal summation

What type of stimulation is caused by rapid, repetitive signals arriving at a synaptic knob, causing progressively larger quantities of calcium to accumulate and leading to synaptic facilitation?

Tetanic

A negative membrane potential indicates which of the following?

The inside of the membrane is negatively charged relative to the outside.

Some neurotransmitters can have either excitatory or inhibitory effects depending on which of the following?

The type of receptors on the postsynaptic cell

Why would the synapses of a memory trace undergo synaptic potentiation?

To allow easier signal transmission along pathway

In a synapse, where are synaptic vesicles located?

axon terminal

soma

cell body of a neuron

The brain and spinal cord are components of the ______ nervous system, while the nerves and ganglia are components of the ______ nervous system

central, peripheral

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

The glial cells that line cavities of the brain and spinal cord and secrete and circulate cerebrospinal fluid are ______.

ependymal cells

Choose all the neurotransmitters that are classified as monoamines.

epinephrine, norepinephrine, dopamine-{catecholamines} histamine, serotonin

Terminal arborization

extensive complex of fine branches at distal end of axon

The plural form of ganglion is ______.

ganglia

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

insulation

Neuroglial cells that act as macrophages within the CNS are ______.

microglia

internodes

myelin covered segments from one gap to the next

Synapses are not fixed for life. In response to experience, they can be modified to make transmission easier or harder. The ability of synapses to change is called synaptic

plasticity

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

postsynaptic

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

presynaptic

What is the role of neural pools in the CNS?

process information

salatory conduction

rapid conduction of impulses when the axon is myelinated since depolarizations jump from node (of Ranvier) to node

Propagation of an action potential down a myelinated axon in which the action potential appears to "jump" from node to node is called _______ conduction.

saltatory

initial segment

short section of nerve fiber between the axon hillock and the first glial cell

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

Neural coding

the way in which the nervous system converts information to a meaningful pattern of action potentials

Neurons with a single process extending from the soma, such as the neurons that carry sensory signals to the spinal cord, are classified structurally as ______ neurons.

unipolar

Choose all of the following statements that are true about sodium?

-Na+ is about 12 times as concentrated in the ECF as in the ICF. -The resting plasma membrane is much less permeable to Na+ than to K+.

What is the approximate ratio of glial cells to neurons?

10:1

The ability of synapses to change is called synaptic plasticity. Which term refers to the neuronal pathways formed during learning?

Memory traces

What are the effectors of motor neurons?

Muscle and gland cells

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

Potential energy

Which type of glial cell produces the myelin sheath in the PNS?

Schwann cell

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

True

When do EPSPs usually occur?

When sodium channels open

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

Working memory

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

dendrites

The type of circuit in which one input nerve fiber synapses with multiple postsynaptic neurons is a ______ circuit.

diverging

Saltatory conduction means which of the following terms?

"Leaping"

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.

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

Choose all that would cause postsynaptic stimulation to end.

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

neuroglia

-They protect the neurons and help them function. -They bind neurons together and provide a supportive scaffold

Which best describes signal conduction in unmyelinated axons?

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

Which neuroglial cell is found in the peripheral nervous system?

Satellite cell

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 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

Excitatory postsynaptic potentials (EPSPs) are usually due to the entry of which type of ion?

Sodium

True or false: 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

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

absolute

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

The knot like swelling in a nerve where neuron cell bodies are found is called a(n)

ganglion

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

Acetylcholine

Sensory (afferent) neurons do which of the following?

Carry signals to spinal cord and brain

What are the two major anatomical subdivisions of the nervous system?

Central and peripheral nervous systems

At a GABA-ergic synapse, the postsynaptic receptor for the GABA neurotransmitter is which type of channel?

Chloride

Which group of neurotransmitters are synthesized from amino acids by removal of the -COOH group?

Monoamines

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

Neural integration

Which term refers to the outermost layer of myelin, containing the nucleus and cytoplasm of the Schwann cell?

Neurilemma

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

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

Immediate memory, which is the ability to hold something in mind for a few seconds, might be based on activity in which type of neural circuit?

Reverberating

Which term is used to describe signal conduction along a myelinated axon?

Saltatory

Afferent neurons are what type of neurons?

Sensory

At its distal end, an axon has an extensive complex of fine branches called what?

Terminal arborization

Which best describes an electrical current?

The movement of charged particles like ions