Transcript Ch. 10 Nervous system: - Grafton School District

Ch. 10 Nervous
system:
Nervous Tissue and Brain
Function of
Relays messages (motor)
Monitors changes in body systems
(sensory)
Responds to stimuli (sensory)
Maintain homeostasis (sensory)
Integrative – information is brought to
CNS info is put together
Central Nervous system
Includes brain and
spinal cord
Control center,
coordinate body
activities
Peripheral Nervous sys.
Nerves that carry
messages to and
from the central
nervous system
Cells of the Nervous
System
Neuroganglia – glial
cells, nerve glue
Supports, protect
and nourish the
neurons
2. Neurons
Parts of :
Cell body
Dendrites – receive
impulse
Axon – carries impulse
away
Myelin sheath- white
fatty material
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Schwann cells (pns)
Neurilemma (outdside
the sheath)
Nodes of Ranvier
Types of Neurons
Sensory neurons (afferent) – carries
impulse to brain and spinal cord.
Types of Neurons
Motor neurons (efferent) – away from
brain and spinal cord.
Types of Neurons
Interneurons or association neurons –
relay impulses from sensory to motor
neurons.
White matter vs Gray
Matter
White matter
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White because of
myelin
Gray matter

Cell bodies,
interneurons,
nonmyelinated fibers
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Nuclei – clusters of
cells in CNS
Ganglia – cell cluster
in PNS
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The Nerve Impulse
Action potential – steps in the nerve
impulse
3 stages of : polarization,
depolarization, repolarization
Step 1: Polarization
Resting state of a neuron
Sodium/possium pump – sodium ions
out of cells and potassium ions into cells
Polarization continued
Inside of the cell is – charged
Outside of cell is + charged
Due to sodium-potassium pump

2 K+ ions go in as 3 Ca++ go out
http://faculty.washington.edu/chudler/intro
b.html
Step 2: Depolarization
Due to stimulation
Inside of the neuron becomes +
charged.
Na+ rushes into the cell
Step 3: repolarization
Return to resting state
Due to the pumping out of K+.
Na+ blocked
Inside of cell negative
Continues to synapse
Synapse
Brain: structure and
function
4 main parts of the brain:
Cerebrum
Diencephalon
Brain stem
Cerebellum
Cerebrum
Largest part of the
brain
Corpus collosum Right and left
hemispheres
Cerebral cortex –
gray matter covering
the cerebrum
Cerebrum Continued
Function of cerebral cortex – learning,
reasoning, language, memory
Markings of: gyri (elevations) and sulci
(grooves)
Diencephalon
Thalamus –
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Relay station for sensory
fibers between cerebrum
and lower brain.
Hypothalamus 
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Body Temperature
Emotions
Hunger
Thirst
Circadian Rhythms
Cerebellum
Coordinatin of
voluntary muscle
movements
Muscle tone
Brain Stem
Midbrain-relay station, hearing, vision
Pons – relay station, breathing rate
Medulla Oblongata – relay center, heart
rate, blood pressure, respiration
Ventricles
Protection
Bone
Meninges – 3 layers of connective
tissue
Cerebrospinal fluid –
Blood brain barrier – cells associated
with blood vessels that supply the brain
with blood.
Aging Brain
Enlargement of the ventricular system: the volume of
the ventricles
Widening of sulci (the grooves) on the surface of the
brain.
Reduced brain weight and brain volume: loss of
neurons.
Neurological disorders: Alzheimer's disease,
Parkinson's disease and stroke are more common in
the elderly.