Transcript Nervous System

Chemical & Electrical
Coordination Systems
The Nervous System…….
Ch 36 Guide
“Life is in the eye of the
beholder”
Evolution of the Nervous System
From brain Stem to Cerebrum
IB.What is the function of the nervous system?
To receive
information from
a sensory neuron
To process
info. by the
brain & spinal cord
To respond by an
effectors
(muscle/gland)
Acupuncture:Stimulation of nerve centers
Alternative views . . . . . .
IA. The basic unit of the nervous
system = neuron?
• Dendrites receive
stimuli
• Nerve cell body
@ nucleus
transmits the
stimuli
• Axon transmits
the impulse to
another dendrite
Axon ending: terminal bud
• Transfers the
electrical nerve
impulse
• By chemical
neurontransmitters
• From one
neuron to the
next
IA2. Two connecting neurons:
Axon ending
Impulse direction
Dendrite of
new neuron
Axon
Cell
Body
REVIEW……………….
• What is the name of the nerve cell ?
• Does the stimulus travel one- way or
down the neuron in two directions?
• Which part receives the stimuli? (The
synapse, dendrites, cell body, or axon)
• Which is covered by a myelin sheath ?
• What is the purpose of the myelin
sheath?
IB2a.Sensory neurons or“receptors”
receive a stimulus from:
•
•
•
•
•
eyes - sight
ears - hearing
nose - smell
skin - touch
mouth - taste
2b. The Central Nervous System:
1) Spinal Cord
2) Brain
• medulla for
breathing
• cerebellum for
balance
• cerebrum for
higher thinking
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2c. Effectors that do actions are the
• Muscles =
voluntary use the somatic system
involuntary use autonomic
system
• Glands =
endocrine organs
that make hormone messengers
Cerebral Cortex= higher thinking
The real thing . . . . . . . .
Parts of the Cerebrum
Cerebellum & “old brain” controls basic body functions
Right versus left Cerebrum
Infrared Tools to Study the brain . . . .
Schizophrenia & a normal brain scan
Any blow to the head does brain
damage Example of amnesia & processing skills
D. What is a synapse ?
Junction of two
neurons
Neurotransmitters
convert the
electrical impulse
into a chemical
message
E. The 2 types of nervous responses?
Voluntary that use
• the brain &
• spinal cord
b. Involuntary or
Autonomic System
• Sympathetic
• Parasympathetic
a.
The involuntary system: Autonomic
basic body functions & reflex arcs
The Autonomic Nervous System
REVIEW:
The Autonomic Nervous System...
• Automatic
• Two parts:
parasympathetic &
sympathetic
• Which is “fight or
flight response” ?
• Which is ordinary
involuntary body
functions ?
E2. Involuntary Reflex Arcs . . .
.
• Use only spinal cord
• Do not go to the
brain
• Follow the R-SIM
pathway
• Examples:
knee jerk, eye blink,
hot stove pull back
R-SIM Reflex arc pathway . . .
• R
receptor neuron receives the stimuli
• S
sensory neuron passes the impulse
on
• I
interneuron at the spinal cord
processes
• M
motor neuron acts
Is Pain part of the Reflex Arc ???
The five types of receptors
• Are highly
specialized
• Receive only one
type of stimuli
• Can be
“overloaded”
when over
stimulated
Sensory Laboratory. . . . . . . . .
PURPOSE:
• Map the distance between touch receptors
• Measure the extent of peripheral vision
• Determine the effects of cone saturation
• Map the taste receptors
• Measure reflex timing
Map of Taste Receptors . . . .
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References:
• World Book Encyclopedia ‘99 software for
hand out illustrations. IBM Software Corp.
• Encarta Encyclopedia ‘99 for multimedia
slide presentations. Microsoft Corp.