Anatomy and Physiology of the CNS Flashcards
The basic functional unit of the brain
neuron
for receiving electrochemical messages
dendrites
a long projection that carries electrical impulses away from the cell body
Axon
Nerve cell bodies
occurring in clusters
ganglia or nuclei
A cluster of cell bodies with
the same function
center
Neurons are
supported, protected, and nourished by what
glial cells
communicate messages from one neuron to another or from
a neuron to a target cell
neurotransmitters
Neurotransmitters
are manufactured and stored in
synaptic vesicles
A neurotransmitter can either _______ or ______ activity of the target
cell
excite or inhibit
acetylcholine
both excitatory and inhibitory
serotonin
inhibitory
dopamine
inhibitory
norepinephrine
excitatory
gamma-aminobutyric acid
inhibitory
enkephalin or endorphin
excitatory
3 major areas of the brain
cerebrum, brain stem, cerebellum
cerebrum is composed of two hemispheres
thalami, hypothalamus, basal ganglia
brain stem is composed of 3
midbrain, pons, medulla
cerebellum is located where
under the cerebrum and behind the brain stem
folded layers of convolutions; accounting for the high level of activity carried out
gyri
anatomic division
sulcus or fissure
separates the cerebrum into the right and left hemispheres
great longitudinal fissure
made up of gray matter approx 2 to 5 mm in depth; contains billions of neuron cell bodies hence the gray appearance
cerebral cortex
makes up the innermost layer and is composed of myelinated nerve fibers and neuroglia cells that form tracts or pathways connecting various parts of the brain with one another
white matter
largest lobe; major functions are concentration, abstract thought, information storage or memory, and motor function; also responsible in large part for a person’s affect, judgment, personality, and inhibitions
frontal lobe
a predominantly sensory lobe; analyzes sensory information and relays the interpretation of this information to other cortical areas and is essential to a person’s awareness of body position in space, size and shape discrimination, and right-left orientation
Parietal lobe
contains auditory receptive areas; plays a role in memory of sound and understanding of language and music
Temporal lobe
for visual interpretation and memory
Occipital lobe
a thick collection of nerve fibers that connects the two hemispheres of the brain; responsible for the transmission of information from one side of the brain to the other
corpus callosum
nuclei for what cranial nerve/s are located in the cerebrum
cranial nerves I and II (olfactory and optic)
relay station for all sensation except smell; all memory, sensation, and pain impulses pass through this section of the brain
thalami
plays an important role in the
endocrine system because it regulates the pituitary secretion of hormones that
influence metabolism, reproduction, stress response, and urine production
hypothalamus
are masses of nuclei located deep in the cerebral
hemispheres that are responsible for control of fine motor movements,
including those of the hands and lower extremities
basal ganglia
connects the pons and the cerebellum with the cerebral
hemispheres; it contains sensory and motor pathways and serves as the center
for auditory and visual reflexes. Cranial nerves III and IV originate in _____
midbrain
situated in front of the cerebellum between the midbrain
and the medulla and is a bridge between the two halves of the cerebellum, and
between the medulla and the midbrain. Cranial nerves V through VIII originate _____; also contain motor and sensory pathways; it also help regulate respiration
the pons
Motor fibers from the brain to the spinal cord and sensory fibers from the
spinal cord to the brain are in the _______; this is where Cranial nerves IX through XII originate; Reflex centers for respiration, blood pressure, heart rate, coughing, vomiting,
swallowing, and sneezing; The reticular
formation, responsible for arousal and the sleep–wake cycle, begins in the
________ and connects with numerous higher structures.
medulla
integrates sensory information to provide
smooth coordinated movement. It controls fine movement, balance, and
position (postural) sense or proprioception
cerebellum
Indentations in the skull base
fossae
provide protection, support, and nourishment
meninges
layers of meninges
dura mater, arachnoid, and pia mater
covers the brain and the spinal cord. It
is tough, thick, inelastic, fibrous, and gray;
dura mater
When
excess pressure occurs in the cranial cavity, brain tissue may be
compressed against these dural folds or displaced around them
herniation
an extremely thin, delicate membrane
that closely resembles a spider web; has cerebrospinal fluid (CSF) in the space below it,
known as the subarachnoid space
arachnoid
are unique finger-like projections that absorb CSF into the venous
system. When blood or bacteria enter the subarachnoid space, the villi
become obstructed and communicating hydrocephalus may result
arachnoid villi
the innermost, thin, transparent layer that hugs the brain
closely and extends into every fold of the brain’s surface.
pia mater
a clear and colorless fluid that is produced in the choroid plexus of the
ventricles and circulates around the surface of the brain and the spinal cord.
cerebrospinal fluid
four ventricles of CSF
right and left lateral & third and fourth ventricles
Blockage of the flow of CSF
anywhere in the ventricular system produces
obstructive hydrocephalus
Circle of Willis
Anterior cerebral artery, anterior communicating artery, posterior communicating artery, posterior cerebral artery, and anterior spinal artery
This barrier is formed by the endothelial cells of the brain’s capillaries, which
form continuous tight junctions, creating a barrier to macromolecules and
many compounds
Blood Brain Barrier
two tracts that conduct sensations
of deep touch, pressure, vibration, position, and passive motion from the same
side of the body.
fasciculus cuneatus and gracilis or the posterior columns
conduct sensory impulses from muscle spindles, providing necessary input for
coordinated muscle contraction
anterior and posterior spinocerebellar tracts
responsible for
conduction of pain, temperature, proprioception, fine touch, and vibratory
sense from the upper body to the brain.
anterior and lateral spinothalamic tracts
Eight Descending Tracts
Anterior and lateral corticospinal tracts, three vestibulospinal tracts, corcticobulbar tract, and the rubrospinal and reticulospinal tracts
conduct motor impulses to the anterior horn cells from the
opposite side of the brain, cross in the medulla, and control voluntary muscle
activity.
anterior and lateral corticospinal tracts
descend uncrossed and are involved in
some autonomic functions (sweating, pupil dilation, and circulation) and
involuntary muscle control.
three vestibulospinal tracts
conducts impulses
responsible for voluntary head and facial muscle movement and crosses at the
level of the brain stem.
corticobulbar tracts
conduct
impulses involved with involuntary muscle movement.
rubrospinal and reticulospinal tracts
Vertebral column consists of
7 Cervical, 12 thoracic, and 5 lumbar vertebrae (sacrum - 5 vertebrae)
Sensory cranial nerves
Cranial nerves I, II, and VIII
Motor cranial nerves
Cranial nerves III, IV, VI, XI, and XII
mixed sensory and motor nerves
cranial nerves V, VII, IX, and X
Spinal cord is composed of
31 spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
each spinal nerve has what roots
ventral roots and dorsal root
regulates the activities of internal organs such
as the heart, lungs, blood vessels, digestive organs, and glands; Maintenance and restoration of internal homeostasis is largely the
responsibility
autonomic nervous system
best known for
its role in the body’s fight-or-flight response. Under stress from either physical
or emotional causes, sympathetic impulses increase greatly.
sympathetic nervous system
what is the main sympathetic neurotransmitter
norepinephrine
