Nervous System Pt. 3 Flashcards
glistening white continuation of the brain stem
Spinal Cord
Provides a two-way conduction pathway to
and from the brain, and it is a major reflex
center
Spinal Cord
Enclosed within the ___, the
spinal cord extends from the ____ of the skull to the ____
vertebral column;
foramen magnum;
first or second lumbar vertebra
spinal cord is cushioned and protected by ____
meninges
In humans, __ pairs of spinal nerves arise from the
cord and exit from the vertebral column to serve the body area close by
31;
The spinal cord is about the size of a thumb for most of
its length, but it is enlarged in the ___ and ___ where the nerves serving the upper and lower
limbs arise and leave the cord
cervical and lumbar
regions
(collection of the spinal nerve)
Cauda equine
Spinal Cord Anatomy (5)
white matter (exterior)
gray matter (interior)
central canal
meninges
nerves
Spinal Cord Anatomy:
_____ – conduction tracts
_____ - mostly cell bodies
Exterior white mater;
Internal gray matter
Spinal Cord Anatomy:
____- filled with cerebrospinal fluid
____-cover the spinal cord
Central canal;
Meninges
White matter of the spinal cord is composed of
______
myelinated fiber tracts
three regions of white matter—
the dorsal column,
lateral column, and
ventral column
All tracts in the dorsal columns are ___tracts that carry sensory input to the brain. The ___ and ___ columns contain both ascending and
descending (motor) tracts
ascending;
lateral and ventral
a bundle of neuron fibers
nerve
Nerve:
Each fiber is surrounded by a delicate connective tissue
sheats called an ___
endoneurium
Nerve:
Groups of fibers are bound by a coarser connective
tissue wrapping, the ___to form ___ or ___
perineurium;
fiber bundles or fascicles.
all the fascicles are bound together by a tough
fibrous sheath, the ___, to form the cordlike nerve
epineurium
Classification of Nerves (3)
Mixed nerves;
Afferent (sensory) nerves;
Efferent (motor) nerves
Classification of Nerves:
– both
sensory and motor
fibers
Mixed nerve
Classification of Nerves:
____ – carry
impulses toward the
CNS
___ – carry
impulses away from
the CNS
Afferent (sensory)
nerves;
Efferent (motor)
nerves
The 12 pairs of cranial nerves primarily serve
the ___ and ___. Only one pair (the ____) extends to the thoracic and
abdominal cavities.
head and neck;
vagus nerves
The cranial nerves are numbered in
___, and in most cases their names reveal the most important structures they
___
sequence;
control
The 31 pairs of human spinal nerves are
formed by the joining of the ___ and ___ of the spinal cord
ventral and dorsal
roots
spinal nerve divided into 2
dorsal ramus and ventral
ramus
smaller ___serve the skin and
muscles of the posterior body trunk.
Dorsal rami
ventral rami of spinal nerves __ through ___ form the _____, which
supply the muscles between the ribs and the
skin and muscles of the anterior and lateral
trunk
T1 through T12;
intercostal nerves
ventral rami of all other spinal nerves
form complex networks of nerves called
____, which serve the motor and sensory needs of the limbs
plexuses
is the motor subdivision of the PNS that
controls body activities automatically.
Autonomic Nervous System
Stabilized internal environment
Consists of only motor nerves
Autonomic Nervous System
two division of Autonomic Nervous System
Sympathetic division
Parasympathetic division
in _____, the cell bodies of the motor neurons are inside the CNS, and their
axons (in spinal nerves and their rami) extend
all the way to the skeletal muscles they serve
somatic division
autonomic nervous system,
has a chain of two motor neurons -
preganglionic neuron and postganglionic axon
_____– “fight-or-flight”
_____– housekeeping
activites
Sympathetic;
Parasympathetic
Response to unusual stimulus
Takes over to increase activities
sympathetic ANS
E” division of sympathetic ANS =
exercise,
excitement, emergency, and
embarrassment
Conserves energy
Maintains daily necessary body functions
parasympathetic ANS
D” division of parasympathetic ANS-
digestion,
defecation, and diuresis
preganglionic neurons of the parasympathetic division are located in ___of several cranial nerves—__,__,__ and __ (the
__being the most important of these) and in the __ through __levels of the
spinal cord
brain nuclei
III, VII, IX, and X; vagus;
S2; S4
Parasympathetic NS
is Also known as ___
craniosacral division.
Sympathetic NS:
preganglionic neurons are in the ___
of the spinal cord from __ through __
gray matter;
T1; L2
Sympathetic NS is also called the _____
thoracolumbar division
a progressive degenerative disease of the
brain that ultimately results in ____
(mental deterioration), memory loss
(particularly for recent events), a short
attention span and disorientation, and
eventual language loss
Alzheimer’s disease (AD); dementia
AD is associated with a shortage of ____ and structural changes in the brain.
acetylcholine
(ACh)
Alzheimer’s disease (AD):
Microscopic examinations of brain tissue
reveal senile plaques (aggregations of ___) littering the brain like
shrapnel between the neurons.
beta-amyloid peptide
Alzheimer’s disease (AD):
Another line of research has implicated a
protein called ___, which appears to bind
microtubule “tracks” together, much like
railroad ties.
tau
basal nuclei problem; persistent tremor at rest
Parkinson’s Disease
Parkinson’s Disease results from degeneration of specific
neurons in the __ of the
midbrain, which normally supply ___to
the basal nuclei.
substantia nigra; dopamine
Genetic disease that strikes during middle
age leads to massive degeneration of the
basal nuclei and cerebral cortex.
Huntington’s Disease
initial symptoms of Huntington’s disease
wild, jerky, and almost
continuous flapping movements called chorea
(Greek for “dance”)
12 cranial nerves (number/name)
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal
Olfactory (Origin/course):
Fibers arise from ____ in the nasal mucosa and synapse with the ____(which in turn, send fibers to the olfactory cortex)
olfactory receptors;
olfactory bulbs
Olfactory (Function):
(sensory/motor/ mixed);
carries impulses for the sense of ___
purely sensory;
smell
Optic (origin/course):
Fibers arise from the ___ of eye and form the ___. Two optic nerves form the ____by partial crossover of fibers; fibers continue to the thalamus as the ____; ___ connect to visual cortex
retina;
optic nerve;
optic chiasma;
optic tracts;
thalamic fibers
Optic (function):
(sensory/motor/ mixed);
carries impulses for ___
sensory; vision
Oculomotor/ Trochlear (origin/course):
fibers run from the ___into the ___
midbrain-eye
Oculomotor (Function):
(sensory/motor/ mixed); supplies motor fibers to four of the six muscles (__, __, __, and __) that direct the eyeball; to the eyelid; and to the internal eye muscles controlling __ and ___
sensory;
superior, inferior, and medial rectus, and inferior oblique;
lens shape and pupil size
Trochlear (function):
(sensory/motor/ mixed);
supplies moto fibers for one ____
motor;
external eye muscle (superior oblique)
Trigeminal (origin/course):
Fibers emerge from the ___and form ___ that run to the ___
pons;
three divisions; face
Trigeminal (functions):
(sensory/motor/ mixed);
conducts ___from the skin of the __and mucosa of the (3); also contains motor fibers that activate the ___
mixed nerve;
sensory impulses ;
face; nose, mouth, and corneas;
chewing muscles
Abducens (origin/course):
fibers leaves the ___and run to the ___
pons; eye
Abducens (function):
(sensory/motor/ mixed);
supplies motor fibers to the _____, which __the eye laterally
motor;
lateral rectus muscle;
rolls
Facial (origin/course):
fibers leave the __and run to the __
pons; face
Facial (functions):
(sensory/motor/ mixed);
activates the muscles of ____ and the ___and ___; carries sensory impulses from the ___ of anterior tongue
mixed nerve;
facial expression; lacrimal; salivary glands;
taste buds
Vestibulocochlear (origin/course):
fibers run from the
___ and ____receptors of the ___ to the ___
equilibrium and hearing ;
inner ear; brain stem
Vestibulocochlear (function):
(sensory/motor/ mixed);
__branch transmits impulses for the sense of __, and ___branch transmits impulses for the sense of ___; small motor component adjusts sensitivity of ___
mixed nerve;
vestiubular; balance;
cochlear; hearing;
sensory receptors
Glossopharyngeal (origin/course):
fibers emerge from the ___and run to the __
medulla; throat
Glossopharyngeal (function):
(sensory/motor/ mixed);
supplies motor fibers to the ___ that promote __and __production; carries sensory impulses from taste buds of the posterior tongue and from chemical and pressure receptors of the ____
mixed nerve;
pharynx (throat); swallowing and saliva;
carotid artery
Vagus (origin/course):
fibers emerge from the ___and descend into the ___ and _____
medulla; thorax and abdominal cavity
Vagus (functions):
(sensory/motor/ mixed);
fibers carry ___ impulses from and ___impulses to the ___, ___, and ___, and ___; most motor fibers are ____fibers that promote ___ activity and help ____
mixed nerve;
sensory; motor;
pharynx, larynx, and the abdominal and thoracic viscera;
parasympathetic;
digestive; regulate heart activity
Accessory (origin/cause):
fibers arise from the _____ and travel to muscles of the ___ and ___
superior spinal cord (C1-C5)*;
neck and back
Accessory (functions):
(sensory/motor/ mixed);
activate the ___and ___
motor:
sternocleidomastoid; trapezius muscles
Hypoglossal (origin/cause):
fibers run form the __to the ___
medulla; tongue
Hypoglossal (functions):
(sensory/motor/ mixed);
control __ movements
motor; tongue
