Chapter 12 (Nervous Tissue)

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

Axonal transport

Labeled line coding depends on which of the following?

Axons carrying sensory information to the brain are activated by specific types of stimuli.

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

This picture shows an inhibitory postsynaptic potential (IPSP). This is usually due to the opening of which type of ion channels?

Chloride or potassium (pg. 446)

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

Conductivity

The visceral motor division of the PNS is also called the autonomic division. Which of the following are functions of this division?

Controlling gland secretion Stimulating smooth muscle Accelerating or decreasing heartbeat

____are the processes of a neuron that usually receive signals from other neurons.

Dendrites

Which factors influence the speed of nerve signal conduction?

Diameter of axon Presence of myelin

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

Efferent

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 glial cell produces and helps circulate cerebrospinal fluid?

Ependymal cells

List the fundamental physiological properties of neurons.

Excitability, conductivity, secretion

Which are names for the cell body of a neuron?

Neurosoma Soma

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

Nodes of Ranvier

Which neurotransmitters are excitatory to some cells and inhibitory to others, depending on the type of receptors on the target cells?

Norepinephrine Acetylcholine

Which are usually found inside the cell body (or soma) of a mature neuron?

Nucleus Mitochondria Rough endoplasmic reticulum

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

Oligodendrocyte

Inhibitory postsynaptic potentials (IPSPs) maybe result from which of the following? Select all that apply.

Opening Cl- channels Opening K+ channels

Inhibitory postsynaptic potentials (IPSPs) maybe result from which of the following?

Opening K+ channels Opening Cl- 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

Which type of axonal transport involves movement up the axon toward the soma?

Retrograde

______ cells are glial cells in the peripheral nervous system that surround somas of neurons in the ganglia, provide electrical insulation, and regulate the chemical environment of neurons.

Satellite

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

Schwann 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 two types of neuroglia are found only in the peripheral nervous system?

Schwann cells and satellite cells

Which type of neuron begins in most body organs and carries information toward the central nervous system?

Sensory neuron

List the three functional classes of neurons.

Sensory neurons Interneurons Motor neurons

Which statements are true about Schwann cells?

They assist in the regeneration of damaged nerve fibers. They form the neurilemma. They form the myelin sheath in the PNS.

Which statements are true about Schwann cells?

They form the myelin sheath in the PNS. They form the neurilemma. They assist in the regeneration of damaged nerve fibers.

What is the primary function of the myelin sheath?

To increase the speed of signal conduction in the axon

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

True

Which lists the structural categories of neurons?

Unipolar, bipolar, anaxonic, and multipolar

Together, the sympathetic and parasympathetic nervous systems make up the entirety of which division of the nervous system?

Visceral motor

This picture shows an excitatory postsynaptic potential (EPSP). When do EPSPs usually occur?

When sodium channels open

Another term for sensory division is ______ division.

afferent

Neurons that have multiple dendrites but no axons, and which do not produce action potentials, are called ______ neurons.

anaxonic

Movement away from the neuron cell body toward an axon ending is called ______ transport.

anterograde

One axon and one dendrite are classified as what?

bipolar neuron

Which type of cell plays a role in the establishment of the blood-brain barrier?

Astrocyte

Which types of glial cells are found in the central nervous system?

Astrocytes Ependymal cells Microglia Oligodendrocytes

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

-70 mV

What is the approximate ratio of glial cells to neurons?

10:1

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

55

Which term describes all neurons that carry signals towards the CNS?

Afferent

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

False

Which type of transport is used to move mitochondria, synaptic vesicles, and small molecules such as glucose toward the distal end of an axon?

Fast axonal transport

______ cells protect the neurons and help them function.

Glial

Which neurotransmitters produce IPSPs?

Glycine GABA

Which term refers to the segment of an axon between the axon hillock and the first glial cell?

Initial segment

Which type of neuron lies entirely within the CNS and carries out the integrative function of the nervous system?

Interneuron

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

Internodes

Slow axonal transport is always anterograde. What about fast axonal transport?

It can be either anterograde or retrograde.

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).

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).

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

Lipids

Inclusions found in neurons include "wear-and-tear" granules that form when lysosomes degrade worn-out organelles and other products. What is the name of the golden-brown pigment that they contain?

Lipofuscin

Choose the major cytoplasmic inclusions in a neuron.

Melanin Glycogen granules Lipid droplets Lipofuscin

Which type of glial cells in the central nervous system fight microorganisms and destroy foreign matter and dead nervous tissue?

Microglia

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

Multipolar

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

Neural integration

Which factors influence the speed of nerve signal conduction?

Neurilemma

Which term refers to the thick outermost coil of a Schwann cell?

Neurilemma

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

Neurons

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

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

Somatic and visceral

______ summation results when EPSPs occurring at multiple synapses add up to threshold at the axon hillock.

Spatial

When EPSPs from several synapses add up to threshold at the axon hillock, this process is called what?

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 (pg. 448)

Which division inhibits digestion?

Sympathetic

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

In order for a peripheral nerve fiber to regenerate it must have which of the following?

The soma and at least some neurilemma intact

Which statements are true regarding postsynaptic potentials?

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

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

dendrites

Motor, or sensory________ sensory , neurons carry signals away from the CNS and they lead to effectors (muscle and gland cells).

efferent

The motor division is also called the ______ division.

efferent

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

ependymal cells

The plural form of ganglion is ______.

ganglia

The trigger zone includes the axon hillock and the______ segment, a region between the axon hillock and the first glial cell.

initial

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

microglia

In the CNS, myelin is produced by glial cells called___________.

oligodendrocytes

Afferent neurons are ______ neurons.

sensory

The sensory division of the PNS is further subdivided into the ______ sensory division, which carries signals from receptors in the skin, muscles, bones, and joints, and the ______ sensory division, which carries signals from organs of the thoracic and abdominal cavities.

somatic, visceral

here 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

What are the two divisions of the visceral motor division?

sympathetic and parasympathetic

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

At its distal end, an axon has an extensive complex of fine branches called a(n) ______.

terminal arborization

The axon hillock and initial segment play an important role in initiating a nerve signal. They are collectively called the ____ zone.

trigger

The region that plays an important role in initiating a nerve signal and is formed by the axon hillock and the initial segment is the ______.

trigger zone

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

An axon lacking a myelin sheath is said to be ______.

unmyelinated