10 Assessment
Describe how the nervous system detects change associated with the body and reacts to that
change to maintain homeostasis. - ANSNeurons react to physical and chemical changes in their
surroundings. Dendrites receive input --> axon carries information through impulses
Distinguish between neurons and neuroglia. - ANSNeurons are the structural and functional
cells reacting to the physical and chemical changes in their environment. Neuroglia is the
supporting cells necessary for nourishing and maintaining the neurons, among other functions.
Which of the following descriptions is accurate?
a. A neuron is a single dendrite, which sends infromation.
b. A neuron has a single axon, which sends information.
c. A neuron many axons, which receive information.
d. A neuron has many dendrites, which send information.
e. A neuron has only axons, no dendrites - ANSb. A neuron has a single axon, which sends
information.
Explain the difference between the central nervous system (CNS) and the peripheral nervous
system PNS. - ANSThe central nervous system (CNS) is composed of the brain and the spinal
cord. The peripheral nervous system (PNS) is composed of all of the peripheral nerves that
connect all of the parts of the body with the CNS.
List three general functions of the nervous system. - ANSSensory—the sensory function is
accomplished by means of sensory receptors that note changes in their environment.
Integrative—the CNS can take the impulses from all of the sensory receptors and combine them
to make perceptions and sensations about the environment.
Motor—the CNS can send impulses along some peripheral nerves to effectors in the muscles
and glands in response to changes in the internal and external environment.
Distinguish a sensory receptor from an effector. - ANSSensory neurons carry nerve impulses
from peripheral body parts into the brain or spinal cord. Interneurons lie entirely within the brain
or spinal cord. Motor neurons carry nerve impulses out of the brain or spinal cord to effectors
outside the nervous system.
Distinguish between the types of activities that the somatic and autonomic nervous systems
control. - ANSThe somatic nervous system oversees conscious (voluntary) activities. The
autonomic nervous system controls viscera and the subconscious (involuntary) actions.
, Match the part of a neuron on the left with the description on the right.
1. Dendrite—
2.Chromatophilic substance—
3. Axon—
4. Cell body—
5. Neurofibrils— - ANS1. Dendrite—C. Highly branched, multiple processes that have spines
2.Chromatophilic substance—E. Rough endoplasmic reticulum
3. Axon—D. Conducts impulses
4. Cell body—B. Part of neuron from from which axon and dendrites extend
5. Neurofibrils—A. Fine threads in an axon
What Schwann cells and oliogdendrocytes have in common, and how do they differ. - ANSBoth
cell types are neuroglial cells. Schwann cells are found in the PNS, oligodendrocytes are part of
the CNS. Schwann cells encase large axons in lipid-rich layers composed of myelin.
Oligodendrocytes produce myelin. In the brain and spinal cord, unmyelinated axons lack
neurilemmae.
Distinguish between myelinated and unmyelinated axons. - ANSA myelinated nerve fiber is one,
which is bound by Schwann cells longitudinally along its length. The
Schwann cells wrap tightly around the nerve fiber and form a myelin sheath. Unmyelinated
nerve fibers lack these sheaths. In this case, these Schwann cells are not wound around the
axons but simply form a grove or valley in which the axon sits. Myelinated (medullated) nerve
fibers appear white. Unmyelinated nerve fibers appear gray.
Explain how Schwann cells encase large axons, including the formation of myelin, the
neurilemma, and the nodes of Ranvier. - ANSSchwann cells encase large axons of peripheral
neurons in lipid-rich sheaths. These layers are composed of myelin. Around the myelin is the
neurilemma. Narrow gaps in between the myelin and Schwann cells are called the nodes on
Ranvier.
Describe the three types of neurons classified on the basis of structure. - ANSNerve fibers can
be classified into three main groups:
Bipolar—bipolar neurons have only two nerve fibers, one is the axon and one is the dendrite.
They are from opposite sides of the cell body.
Unipolar—unipolar neurons have a single nerve fiber extending from the cell body. From there it
branches in two directions; one branch extends into a peripheral body part and serves as a
dendrite. The other extends into the CNS and acts like an axon.
Multipolar—multipolar neurons have one axon and many other extensions from the cell body
that serve as dendrites.
Describe the three types of neurons classified on the basis of function. - ANSNerve fibers can
be classified into three groups: