A&P The Nervous System Midterm Exam
Questions 100% Well Answered.
what are 4 roles of the nervous system? - Answer coordinates all body systems, detects and responds to
stimuli (changes), brain and spinal cord act as switching centers, nerves carry messages to and from
centers
what are the 2 structural divisions of the nervous system? - Answer the central nervous system (CNS)
and the peripheral nervous system (PNS)
what does the CNS contain? - Answer the brain and spinal cord
what does the PNS contain? - Answer all the nerves outside of the CNS: the cranial and spinal nerves
what is the difference between the cranial and spinal nerves? - Answer cranial nerves carry impulses to
and from the brain; spinal nerves carry impulses to and from the spinal cord
what are the two functional subdivisions of the peripheral nervous system (PNS)? - Answer somatic
nervous system (SNS) and autonomic/visceral nervous system (ANS)
effector - Answer any tissue or organ that carries out a nervous system command, all of which are
muscles or glands
somatic nervous system (SNS) - Answer *control*: voluntary
*effectors*: skeletal muscle
autonomic nervous system (ANS) - Answer *control*: involuntary
*effectors*: smooth muscle, cardiac muscle, and glands
,what other name is the autonomic nervous system referred to as and why? - Answer the visceral
nervous system because its effectors are smooth muscle, cardiac muscle, and glands, which are found in
the soft body organs, the viscera
could dividing the PNS and its effectors by function be misleading? - Answer yes, because the
diaphragm, a skeletal muscle, typically functions in breathing without conscious thought; also, we have
certain rapid reflex responses involving skeletal muscles that do not involve the brain
can people be trained to consciously control involuntary functions? - Answer yes, people can learn to
control blood pressure and heart rate by training techniques known as biofeedback
what is the difference between neurons and nerves? - Answer neurons are the conducting cell of the
nervous system; nerves are bundles of neuron fibers outside of the central nervous system (CNS)
what is a distinguishing feature of neurons? - Answer dendrites and axons: the long, threadlike fibers
that extend out from the cell body and carry impulses across the cell
what are the 3 structures of a neuron? - Answer dendrites, axons, myelin sheath
what are the similarities and differences between dendrites and axons? - Answer both are neuron fibers
the carry impulses across the cell; dendrites conduct impulses *to* the cell body; axons conduct
impulses *away from* the cell body
dendrites - Answer *description*: highly branched, tree-like appearance
*function*: receptors in the nervous system, that is, they receive a stimulus that begins a neural
pathway; carry impulses to the cell body
axons - Answer *description*: a neuron has only 1 axon, which can extend up to 1 m and give off many
branches
*function*: carry impulses away from the cell body; these impulses may be delivered to another neuron,
to a muscle, or to a gland
,the myelin sheath - Answer *description*: some axons are covered with this whitish, fatty substance
called myelin
*function*: myelin insulates and protects the fiber
myelinated vs. nonmyelinated - Answer myelinated axons are called white fibers and are found in
*white matter* of the brain and spinal cord as well as most nerves throughout the body; the fibers and
cell bodies of the *gray matter* are not covered with myelin
PNS myelin sheath vs. CNS myelin sheath - Answer in the *PNS*, myelin is actually entire cells, known
as schwann cells, that are wrapped around the axon like a jelly role; in the *CNS* the myelin sheath is
formed by another type of cell, the oligodendrocytes (literally meaning "cell with few dendrites")
schwann cells - Answer myelin sheath of the PNS; a type of neuroglia; cell bodies and most of the
cytoplasm get squeezed into the outermost layer of the cell wrapping, known as the neurilemma; when
the sheath is complete, small spaces, called nodes, remain between the individual cells and are
important in speeding nerve impulse conduction; these cells help injured neurons regenerate and
undamaged cells near the injury divide to produce replacement cells that remove the damaged tissue
and provide a mold (tube) to guide the extension of the new axon; repair is a slow and uncertain process
obligodendrocytes - Answer myelin sheath of the CNS; a type of neuroglia; one cell sends cellular
extensions to myelinate several neighboring axons; the cytoplasm and nucleus remain with the cell so
the CNS neurons do not have a neurilemma; these cells can only partially restore the myelin coating if it
gets damaged, and they can not guide axon regeneration to the same extent as schwann cells; if CNS
neurons are injured, the damage is almost always permanent
what is the job of neurons? - Answer to relay information to or from the CNS or to different places
within the CNS itself
what are the 3 functional categories of neurons? - Answer sensory (afferent) neurons; motor (efferent)
neurons; interneurons (central/association neurons)
sensory (afferent) neurons - Answer *function*: conduct impulses TO the spinal cord and brain
*example*: if you touch a sharp object with your finger sensory neurons will carry impulses generated
by the stimulus to the CNS for interpretation
, motor (efferent) neurons - Answer *function*: carry impulses FROM the central nervous system TO
muscles and glands (effectors)
*example*: the CNS responds to the pain of touching a sharp object by directing skeletal muscle in your
arm to flex and withdraw your hand
interneurons (central/association neurons) - Answer *function*: relay information FROM place to place
WITHIN the central nervous system
*example*: in addition to immediate withdrawal from pain, impulses may travel to other parts of the
CNS to help retain balance as you withdraw your hand or to help you learn how to avoid sharp objects
neuron fibers - Answer *description*: bundles of dendrites and axons that vary in size; make up fiber
bundles
*location*: everywhere in the nervous system; many of them are bundled together in a single nerve or
tract (just like an electric cable contains many wires)
nerve - Answer neuron fiber bundle in the PNS; may contain all sensory fibers, all motor fibers, or a
combination of both types of fibers
sensory (afferent) nerves - Answer a few of the cranial nerves contain only sensory fibers, so they
*only* conduct impulses *toward* the brain
motor (efferent) nerves - Answer a few of the cranial nerves contain only motor fibers, so they *only*
conduct impulses *away from* the brain
mixed nerves - Answer *most* of the cranial nerves and *all* of the spinal nerves contain *both*
sensory and motor fibers, so their *impulses* may be traveling in 2 directions (toward or away from the
CNS), but each *individual fiber* in the nerve is carrying impulses in 1 direction only
tract - Answer neuron fiber bundle in the CNS; tracts in the *brain* conduct impulses between regions;
tracts in the *spinal cord* conduct impulses to and from the brain
how is the structure of muscle fibers (cells in muscles) similar to that of neuron fibers (cells in
nerves/tracts)? - Answer their individual fibers are both organized into *fascicles* and bound together
Questions 100% Well Answered.
what are 4 roles of the nervous system? - Answer coordinates all body systems, detects and responds to
stimuli (changes), brain and spinal cord act as switching centers, nerves carry messages to and from
centers
what are the 2 structural divisions of the nervous system? - Answer the central nervous system (CNS)
and the peripheral nervous system (PNS)
what does the CNS contain? - Answer the brain and spinal cord
what does the PNS contain? - Answer all the nerves outside of the CNS: the cranial and spinal nerves
what is the difference between the cranial and spinal nerves? - Answer cranial nerves carry impulses to
and from the brain; spinal nerves carry impulses to and from the spinal cord
what are the two functional subdivisions of the peripheral nervous system (PNS)? - Answer somatic
nervous system (SNS) and autonomic/visceral nervous system (ANS)
effector - Answer any tissue or organ that carries out a nervous system command, all of which are
muscles or glands
somatic nervous system (SNS) - Answer *control*: voluntary
*effectors*: skeletal muscle
autonomic nervous system (ANS) - Answer *control*: involuntary
*effectors*: smooth muscle, cardiac muscle, and glands
,what other name is the autonomic nervous system referred to as and why? - Answer the visceral
nervous system because its effectors are smooth muscle, cardiac muscle, and glands, which are found in
the soft body organs, the viscera
could dividing the PNS and its effectors by function be misleading? - Answer yes, because the
diaphragm, a skeletal muscle, typically functions in breathing without conscious thought; also, we have
certain rapid reflex responses involving skeletal muscles that do not involve the brain
can people be trained to consciously control involuntary functions? - Answer yes, people can learn to
control blood pressure and heart rate by training techniques known as biofeedback
what is the difference between neurons and nerves? - Answer neurons are the conducting cell of the
nervous system; nerves are bundles of neuron fibers outside of the central nervous system (CNS)
what is a distinguishing feature of neurons? - Answer dendrites and axons: the long, threadlike fibers
that extend out from the cell body and carry impulses across the cell
what are the 3 structures of a neuron? - Answer dendrites, axons, myelin sheath
what are the similarities and differences between dendrites and axons? - Answer both are neuron fibers
the carry impulses across the cell; dendrites conduct impulses *to* the cell body; axons conduct
impulses *away from* the cell body
dendrites - Answer *description*: highly branched, tree-like appearance
*function*: receptors in the nervous system, that is, they receive a stimulus that begins a neural
pathway; carry impulses to the cell body
axons - Answer *description*: a neuron has only 1 axon, which can extend up to 1 m and give off many
branches
*function*: carry impulses away from the cell body; these impulses may be delivered to another neuron,
to a muscle, or to a gland
,the myelin sheath - Answer *description*: some axons are covered with this whitish, fatty substance
called myelin
*function*: myelin insulates and protects the fiber
myelinated vs. nonmyelinated - Answer myelinated axons are called white fibers and are found in
*white matter* of the brain and spinal cord as well as most nerves throughout the body; the fibers and
cell bodies of the *gray matter* are not covered with myelin
PNS myelin sheath vs. CNS myelin sheath - Answer in the *PNS*, myelin is actually entire cells, known
as schwann cells, that are wrapped around the axon like a jelly role; in the *CNS* the myelin sheath is
formed by another type of cell, the oligodendrocytes (literally meaning "cell with few dendrites")
schwann cells - Answer myelin sheath of the PNS; a type of neuroglia; cell bodies and most of the
cytoplasm get squeezed into the outermost layer of the cell wrapping, known as the neurilemma; when
the sheath is complete, small spaces, called nodes, remain between the individual cells and are
important in speeding nerve impulse conduction; these cells help injured neurons regenerate and
undamaged cells near the injury divide to produce replacement cells that remove the damaged tissue
and provide a mold (tube) to guide the extension of the new axon; repair is a slow and uncertain process
obligodendrocytes - Answer myelin sheath of the CNS; a type of neuroglia; one cell sends cellular
extensions to myelinate several neighboring axons; the cytoplasm and nucleus remain with the cell so
the CNS neurons do not have a neurilemma; these cells can only partially restore the myelin coating if it
gets damaged, and they can not guide axon regeneration to the same extent as schwann cells; if CNS
neurons are injured, the damage is almost always permanent
what is the job of neurons? - Answer to relay information to or from the CNS or to different places
within the CNS itself
what are the 3 functional categories of neurons? - Answer sensory (afferent) neurons; motor (efferent)
neurons; interneurons (central/association neurons)
sensory (afferent) neurons - Answer *function*: conduct impulses TO the spinal cord and brain
*example*: if you touch a sharp object with your finger sensory neurons will carry impulses generated
by the stimulus to the CNS for interpretation
, motor (efferent) neurons - Answer *function*: carry impulses FROM the central nervous system TO
muscles and glands (effectors)
*example*: the CNS responds to the pain of touching a sharp object by directing skeletal muscle in your
arm to flex and withdraw your hand
interneurons (central/association neurons) - Answer *function*: relay information FROM place to place
WITHIN the central nervous system
*example*: in addition to immediate withdrawal from pain, impulses may travel to other parts of the
CNS to help retain balance as you withdraw your hand or to help you learn how to avoid sharp objects
neuron fibers - Answer *description*: bundles of dendrites and axons that vary in size; make up fiber
bundles
*location*: everywhere in the nervous system; many of them are bundled together in a single nerve or
tract (just like an electric cable contains many wires)
nerve - Answer neuron fiber bundle in the PNS; may contain all sensory fibers, all motor fibers, or a
combination of both types of fibers
sensory (afferent) nerves - Answer a few of the cranial nerves contain only sensory fibers, so they
*only* conduct impulses *toward* the brain
motor (efferent) nerves - Answer a few of the cranial nerves contain only motor fibers, so they *only*
conduct impulses *away from* the brain
mixed nerves - Answer *most* of the cranial nerves and *all* of the spinal nerves contain *both*
sensory and motor fibers, so their *impulses* may be traveling in 2 directions (toward or away from the
CNS), but each *individual fiber* in the nerve is carrying impulses in 1 direction only
tract - Answer neuron fiber bundle in the CNS; tracts in the *brain* conduct impulses between regions;
tracts in the *spinal cord* conduct impulses to and from the brain
how is the structure of muscle fibers (cells in muscles) similar to that of neuron fibers (cells in
nerves/tracts)? - Answer their individual fibers are both organized into *fascicles* and bound together
