Download CHAPTER 11: NERVOUS SYSTEM II: DIVISIONS OF THE

CHAPTER 11: NERVOUS SYSTEM II: DIVISIONS OF THE NERVOUS
SYSTEM
OBJECTIVES:
1.
Outline the major divisions of the nervous system.
NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM
(BRAIN & SPINAL CORD)
(INTERNEURONS)
SENSORY
(INPUT INTO CNS)
(AFFERENT NEURONS)
PERIPHERAL NERVOUS SYSTEM
(CRANIAL NERVES & SPINAL NERVES)
MOTOR
(OUTPUT FROM CNS)
(EFFERENT NEURONS)
SOMATIC
(EFFECTORS: SKELETAL MUSCLE)
(CONSCIOUS CONTROL)
PARASYMPATHETIC
(HOMEOSTASIS)
(NT: ACETYLCHOLINE)
AUTONOMIC
(EFFECTORS: SMOOTH MUSCLE,
CARDIAC MUSCLE, GLANDS)
(UNCONSCIOUS CONTROL)
SYMPATHETIC
(FIGHT-OR-FLIGHT)
(NT: NOREPINEPHRINE)
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2.
Discuss how the organs of the central nervous system (CNS) are protected in terms
of bones, membranes and fluid.
Bones
Protects the brain = 8 bones of cranium;
Protects spinal cord = vertebral column
Membranes (Meninges)
Membranes that surround and protect the
brain and the spinal cord
Cerebrospinal cord
Provides protective cushion, nourishes,
maintains ion and NT concentrations
3.
Name the three meninges and discuss the differences between how they are
structured around the brain and spinal cord.
Dura mater - outer most layer; DRCT; attached to bone of skull but not to bone of
vertebrae = epidural space
Arachnoid mater- middle layer = thin delicate, underside of dura mater
Pia mater- inner layer that covers brain and spinal cord
4.
Name the space that lies between two of the meninges surrounding both the brain
and spinal cord, and name the fluid that fills this space.
Subarachnoid space : filled with cerebrospinal fluid and lined by ependymal cells
5.
Name the additional space that is found around the spinal cord, and name the
fluid that fills this space.
Epidural space, filled with loose CT and fat
6.
Define the term meningitis.
An inflammation of the meninges (caused by viral or bacterial infection)
7.
Discuss the external structure of the spinal cord in terms of its length, start, end,
number of segments, and enlarged areas.
About 17 inches long, the start is the foramen magnum, it tapers to a point and
terminates near the intervertebral disc that separates the first/ second lumbar
vertebrae in a point called the conus medullaris
Has 31 segments that give rise to 31 pairs of spinal nerves
Enlargement are in the cervical and lumbar regions.
About the thickness of thumb
Remnant of distal pia mater = filum terminale
8.
Name the terminal point of the spinal cord, the term used for how the remaining
spinal nerves appear, and the point at which they terminate.
Conus medullaris
cauda equina
filum terminale
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9.
Illustrate the cross-sectional anatomy of the spinal cord and label all parts.
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CHAPTER 11: NERVOUS SYSTEM II: DIVISIONS OF THE NERVOUS
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10.
Name the cells that line the central canal and identify the fluid that fills the central
canal.
Lined by ependymal cells, and is filled with cerebrospinal fluid
11.
Distinguish between a "horn" and a "column" in the spinal cord.
A horn is gray matter and they form inner butterfly
A column is white matter and they lie on outside of spinal cord
12.
Explain which portion of the spinal cord is the location for the major nerve tracts,
and discuss their significance.
Ascending tracts are sensory : lie primarily in posterior white columns
Descending are motor: lie primarily in anterior white columns
13.
Compare and contrast ascending and descending tracts.
See #12 above
14.
Discuss the general characteristics of nerve tracts.
They are conduits for nerve impulse to and from the brain; cross-over at some point in
spinal cord; are composed of 2-3 interneurons in sequence.
15.
Discuss the features located on the periphery of the spinal cord in cross-section.
PNS: Dorsal Root Ganglion (cell bodies of sensory neurons) leading to dorsal root into
Posterior white columns in SC; ventral root leading away from Anterior white columns.
Fusion of dorsal root and ventral root = spinal nerve.
16.
Define the term ganglion and discuss the specificities of a dorsal root ganglion.
A ganglion is a bundle of cell bodies outside in PNS.
17.
Define the term nerve pathway.
The route traveled by a nerve impulse through the nervous system.
18.
List and discuss the components in a reflex arc.
A sensory receptor which reacts to a stimulus
A sensory neuron that conducts the afferent impulse to the CNS
The integration center (in interneuron of CNS)
The motor neuron that conducts the efferent motor impulse from the CNS to an
effector
The effector which is muscle fibers or glands that respond to the motor impulse
19.
Discuss the significance of reflex arcs.
They are used to show physician that all parts of nerve pathway are functioning from
SR to effector; They are the simplest demonstration of a nerve pathway; most are
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protective
20.
Fully discuss the three-fold function of the nervous system.
A.
Draw a simple nerve pathway that involves three neurons (with cell parts
labeled), and track (on your diagram) the transmission of a nerve impulse
throughout this pathway.
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21.
Name and locate the four major regions of the brain.
Cerebrum- largest
Diencephalon
Brainstem
Cerebellum
22.
Discuss the structure of the cerebrum in terms of its size, two major divisions,
surface appearance, major grooves, and lobal divisions.
Largest; divided into two hemispheres; bumps on surface are convulsions; shallow
grooves are sulci; deep grooves are fissures.
Longitudinal Fissure separates two hemispheres; Transverse Fissure separates
cerebrum from cerebellum
Each hemisphere has a frontal lobe, a parietal lobe, an occipital lobe, and a temporal
lobe
23.
Identify the composition of the bulk of the cerebrum.
The cerebral medulla is composed of white matter; and the cerebral cortex is composed
of gray matter.
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24.
Define the term cerebral cortex and discuss its composition and significance.
The outer cerebral cortex is composed of gray matter = bundles of cell bodies in CNS
These cell bodies serve as the destination site for all incoming sensory impulses and the
initiation site for all outgoing motor impulses.
25.
Compare the major functional areas (sensory and motor) of the cerebral cortex in
terms of location and function (a diagram may help here).
Frontal Primary motor cortex – initiates all motor impulses to skeletal muscles;
Broca’s Area in left frontal lobe – controls muscles of speech
Parietal cortex – general sensation
Occipital cortex – sense of vision
Temporal cortex – sense of hearing
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26.
Explain what is meant by an association area of the cerebral cortex and
name a few association traits.
Any traits that are not motor or sensory; all four lobes of cerebrum are involved in
association traits
Personality, memory, emotions, problem solving, etc
27.
Name the term referring to the measurement of brain activity. EEG
28.
Explain what is meant by hemisphere dominance, and name the hemisphere that
is dominant in most people.
Left hemisphere is dominant on 90% of right handed people language related activities;
Right hemisphere controls musical, art, etc
29.
Define the term basal nuclei and explain their location and function.
Many areas deep in brain working together as outgoing motor relay station
30.
Name the interconnected cavities within the cerebrum and brain stem and
identify the fluid that fills these spaces and name the cells that line these spaces.
Ventricles- cerebrospinal fluid - ependymal cells
31.
Name the specialized capillaries that secrete CSF and denote their location on a
diagram.
Choroid plexuses
32.
Trace a drop of CSF from where it is secreted to where it is reabsorbed back into
the blood stream.
a. Choroid plexuses
b. Lateral ventricles
rd
c. 3 ventricle
d. Cerebral aqueduct
th
e. 4 ventricle
f. Down central canal of spinal cord and/or
g. Into subarachnoid spaces
h. Arachnoid granulations reabsorb CSF into blood
stream (dural sinuses)
33.
Define the terms arachnoid granulations and dural sinuses.
Extensions of arachnoid mater that extend into dural sinuses (venous blood).
They reabsorb CSG back into bloodstream
34.
Discuss the functions of CSF.
Cushions
Ion source for nerve impulses; neurotransmitters
Circulation
35.
Discuss the two important areas of gray matter within the diencephalon, in terms
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of location and function.
Thalamus
Incoming sensory relay station for all senses, except smell
36.
Identify the three major parts of the brain stem.
Midbrain- pupillary and auditory reflexes
Pons- controls breathing rate
Medulla - cardiac center, vasomotor center, center for rhythm of breathing
37.
Discuss the midbrain in terms of its location, composition and function.
Located between dicephalon and pons
Reflexes activity, auditory and pupillary
38.
Name the location of the pneumotaxic area (Pontine Area) of the respiratory
center.
See above: bulge = Pons – controls rate of breathing
39.
Discuss the importance of the medulla (oblongata).
Maintains homeostasis through hypothalamic regulation:
Cardiac center controls heart rate and rhythm, vasomotor center controls blood
pressure, respiratory center controls rhythm of breathing.
40.
Briefly explain the significance of the limbic system and reticular formation.
Limbic system is composed of several areas that work together to control emotions and
circadian rhythm
Reticular formation controls brain alertness
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41.
Locate the cerebellum on a diagram, and discuss its structure and function.
Arbor vitae = white matter within Gray matter. Cerebellum controls balance and
equilibrium.
42.
Discuss the general structure of a nerve.
Endoneurium- around each myelinated axon
Perineurium around each fascicle of axons
Epineurium around each nerve.
43.
Distinguish between a mixed, sensory, and motor nerve.
Mixed nerves have both sensory and motor fascicles; CN V, VII, IX, X and all spinal nerves
Sensory nerves have only sensory fascicles; CN I, II, VIII
Motor nerves have only motor fascicles; CN III, IV, VI, XI, XII
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44.
Numeral
Name the twelve pairs of cranial nerves, designate them by Roman numeral,
discuss their function, and designate them as sensory, motor, or mixed.
Summary Table for Cranial Nerves
Name
Function
Sensory, Motor, or
Mixed Nerve
I
OLFACTORY
OLFACTION/SMELL
SENSORY
II
OPTIC
VISION
SENSORY
III
OCULOMOTOR
MOVE EYE
MOTOR
IV
TROCHLEAR
MOVE EYE
MOTOR
V
TRIGEMINAL
CHEWING/MASTICATION AND
SENSORY FROM FACE
MIXED
VI
ABDUCENS
MOVE EYE
MOTOR
VII
FACIAL
FACIAL EXPRESSION; TASTE
MIXED
VIII
VESTIBULOCOCHLEAR
HEARING AND EQUILIBRIUM
SENSORY
IX
GLOSSOPHARYNGEAL
MOVE MUSCLES OF TONGUE
AND PHARYNX; TASTE
MIXED
X
VAGUS
INNERVATE VISCERAL SMOOTH
MUSCLE; SENSATIONS FROM
SAME
MIXED
XI
ACCESSORY
MOVE NECK MUSCLES
MOTOR
XII
HYPOGLOSSAL
MOVE TONGUE
MOTOR
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45.
Discuss the characteristics of spinal nerves in terms of number, coverings, and
composition.
Spinal nerves are all mixed nerves
There are 31 pair of spinal nerves
Connective Tissue coverings are same as above
46.
Discuss how a spinal nerve is distributed.
The major portion is called a ventral ramus, which we will term a “spinal nerve”.
47.
Define the term nerve plexus and explain its significance.
A branching network of spinal nerves: they do not extend directly to the body part but
they form networks.
Plexuses are efficient and prevent complete paralysis of a limb if damage to a spinal
nerve occurs.
48.
Name the three/four major nerve plexuses and briefly discuss the areas that each
innervates.
Cervical plexus (C1-C4)- the neck and Lumbosacral plexus – (T12-S5) anterior
diaphragm
and medial thigh and posterior lower
limbs
Brachial plexus (C5-T1)- upper limbs
49.
Compare the somatic and autonomic divisions of the NS in terms of motor neurons
involved, the presence or absence of ganglia, neurotransmitter type, and effector
type.
Somatic
Autonomic
One motor neuron
2 motor neurons
Effectors are skeletal muscle
Effectors are cardiac muscle, smooth
muscle, glands
Voluntary control
Involuntary control
50.
Describe the general function of the ANS. The ANS regulates involuntary actions
51.
Name the two major divisions of the ANS, and describe their general function.
sympathetic
parasympathetic
Fight or flight
Maintains homeostasis
52.
Compare the length of a preganglionic and postganglionic neuron in the
sympathetic and parasympathetic division of the ANS.
sympathetic
parasympathetic
Pre is short
Pre is long and extends to at or near effector
Post is long
Post is short
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53.
Define the term ganglion, and compare the location of sympathetic and
parasympathetic ganglia.
Ganglion- a bundle of cell bodies in PNS; the two ANS motor neurons synapse at a
ganglion (AT of first synapses with CB of 2nd)
Sympathetic- are located on either side of the spinal cord.
Parasympathetic - located at or near the effector
54.
Compare the origin of a sympathetic preganglionic neuron with a parasympathetic
preganglionic neuron.
Preganglionic origination of sympatric fibers is from the thoracolumbar regions of the
spinal cord
Preganglionic origination of parasympathetic arises from either the cranial region of
brain or sacral region of spinal cord
55.
Distinguish between cholinergic and adrenergic fibers (axons).
ACh is released by the cholinergic fibers
Norepinephrine is released
adrenergic fibers.
by
the
56.
Describe the two types of cholinergic and adrenergic receptors.
Cholinergic Receptors
Adrenergic
Nicotinic and muscarinic
Alpha and Beta
57.
Compare and contrast the two divisions of the ANS in terms of their name, general
function, origin of preganglionic fiber, length of preganglionic fiber, location of
ganglia, and type of neurotransmitter secreted by the postganglionic fiber.
General
Function
maintain homeostasis
to survive stressful or
“fight or flight” situations
Origin of
Preganglionic fiber
from cranial region of brain
or sacral region of spinal
cord
from thoracic or lumbar
region of spinal cord
Length of
Preganglionic fiber
Long
short
Location of Ganglia
at or near effector
alongside spinal cord
NT secreted by post-
acetylcholine
norepinephrine
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ganglionic fiber
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