Bio Comprehension Q 12.1-12.4

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 nervous system plays an important role in maintaining homeostasis. List, in order, the basic steps that describe how the nervous system carries out this task.

1. information received by the sensory receptors is transmitted to the CNS 2. Information is processed and an appropriate response is determined 3. a command is issued to effectors such as muscles or glands

What is the approximate ratio of glial cells of neurons?

10:1

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

Peripheral nervous system

Neurons that convey information to the CNS (indicated by the arrow labeled A) are called sensory neurons, or ____neurons.

afferent

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

afferent

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

anaxonic

What type of glial cell is indicated by the arrow labeled A?

astrocyte

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 oligodendrocytes microglia ependymal cells

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

Which factors influence the speed of nerve signal conduction?

presence of myelin diameter of axon

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

satellite and schwann cells

Which neuroglial cell is found in the peripheral nervous system?

satellite cell

What is labeled A

schwann

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

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

schwann cell

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

sensory neuron

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

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

somatic and visceral

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

Which division inhibits digestion?

sympathetic

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

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

synaptic knobs

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

terminal arborization

Which part of the neuron is indicated by the arrow

terminal arborization

what is true about schwann cells?

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

What is arrow A

Oligodendrocytes

Another term for sensory division is ____ division.

afferent

What is the primary function of the myelin sheath?

To increase the speed of signal conduction in the axon

What is the area of the neuron indicated by the arrow labeled A.

axon collateral

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

What type of neuron is shown in the image?

bipolar

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

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

central, peripheral

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

conductivity

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

dendrites

___ are processes of a neuron that usually receive signals from other neurons.

dendrites

The motor division is also called the ___ division.

efferent

The motor division is also called the___ division.

efferent

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

efferent

Choose the name of the thin layer of fibrous connective tissue found around myelin in nerve fibers of the peripheral nervous system.

endoneurium

Which cell type is indicated by the arrow labeled A?

ependymal

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

ependymal cells

Which glial cell produces and help circulate cerebrospinal fluid?

ependymal cells

List the fundamental physiological properties of neurons.

excitability, conductivity, secretion

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

Which are functions of astrocytes?

form blood-brain barrier secrete nerve growth factors regulate chemical composition of tissue fluid convert blood glucose to lactate for neurons to use for fuel

The plural form of ganglion is ___.

ganglia

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

ganglion

Choose the major cytoplasmic inclusions in a neuron.

glycogen granules lipid droplets melanin lipofusion

The trigger zone includes the axon hillock and the _____segment (indicated by the letter A), a region between the axon hillock and the first glial cell.

initial

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

what is the arrow A labeled?

interneuron

List the three functional classes of neurons

interneurons motor neurons sensory neurons

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

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

What are the major cytoplasmic inclusions in a neuron?

lipofuscin melanin lipid droplets glycogen granules

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

microglia

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

microglia

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

mitochondria nucleus rough endoplasmic recticulum

Which division of the PNS carries signals from the CNS to glands and muscle cells?

motor

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

multipolar

The picture shows the most common structural type of neuron. It contains one axon and multiple dendrites, and it is classified as a(n) ______ neuron.

multipolar

What are the effectors of motor neurons?

muscles and glands

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

nervous system endocrine system

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

neurilemma

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

neurons

What are names for the cell body of a neuron?

neurosoma soma

The ______ (the cell body of a neuron) gives rise to branch-like processes called ______, which are the primary sites for receiving signals from other neurons.

neurosoma, dendrites

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

the soma and at least some neurilemma intact

Choose the characteristics of neuroglia

they protect the neurons and help them function they bind neurons together and provide a supportive scaffold

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

T or F: the neuron shown in this picture is structurally classified as an anaxonic neuron

true

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

true

The type of neuron shown here is___

unipolar

Which type of neuron has one single process that branches like a T into a peripheral fiber and a central fiber?

unipolar

Which lists the structural categories of neurons?

unipolar, bipolar, anaxonic, and multipolar

An axon lacking a myelin sheath is said to be_____.

unmyelinated

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

visceral motor

What term is another name for the autonomic nervous system?

visceral motor division