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 neuronTo process info. by the brain & spinal cordTo 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 neuron-transmitters

• From one neuron to the next

IA2. Two connecting neurons:

Axon

Cell Body

Axon ending

Dendrite ofnew neuron

Impulse direction

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 bw

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?

a. Voluntary that use

• the brain &

• spinal cord

b. Involuntary or

Autonomic System

• Sympathetic

• Parasympathetic

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

• Ssensory neuron passes the impulse on

• Iinterneuron at the spinal cord processes

• Mmotor 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 . . . . B w

bw

References:

• World Book Encyclopedia ‘99 software for hand out illustrations. IBM Software Corp.

• Encarta Encyclopedia ‘99 for multimedia slide presentations. Microsoft Corp.