Human Nervous System

Most Remarkable Communication Center Regulates the actions of organs Monitors the senses Controls one’s thinking, learning & memory capacity Specialized nerve receptors in sensory organs of

eyes, ears, nose Constantly send data to brain at 300 mph

February 2, 2010

New Notebooks… Get ‘er done!!

Please turn to 36.1 page 973

Draw a neuron on the left side… Label it please…

Notes 36.1

Nervous System!!Chapter 36

Neurons – nerve cells which conduct impulses thru/out body - can be 1 m long in humans

Composed of 3 parts: 1. Cell body – contains the nucleus, interprets 2. Axon – carries impulses away from the cell

body 3. Dendrite – receive stimuli and conduct

towards the cell body Synapse – space that separates neurons from

each other, a chemical neurotransmitter is released that bridges the gap and is unidirectional

1. 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

Resting neuron has a polarized membrane “– “ inside the cell, “+”outside the cell,

that can transmit an electrical charge or impulse Depolarization - increase in Na+ inside

cell give it a positive charge (wave) moves at speeds > 130m/sec

myelin - covers the axon (white matter) allows impulse to “jump”

gray matter - found in CNS brain, spinal cord

Axon ending: terminal bud

Transfers the electrical nerve impulse

By chemical neuron-transmitters

From one neuron to the next

Nerve depolarization is all or none principle

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)

The Central Nervous System:1) Spinal Cord

2) Brainmedulla for

breathingcerebellum for

balancecerebrum for higher thinking bw

Central Nervous System (CNS) Central Nervous System (CNS) - brain and

spinal cord, receives and processes info and makes appropriate response

1. Cerebrum - 2 hemispheres, intelligence, memory, verbal, language, senses, “bridge connection”

2. Cerebellum - controls balance, posture, coordination

3. Medulla Oblongata – involuntary responses like heartbeat, breathing

Right versus left Cerebrum

Peripheral Nervous System Peripheral Nervous

System (PNS) - all nerve pathways from the CNS to rest of body

1. Somatic Nervous System – voluntary system, connection between spinal cord cranial & spinal nerves, skinReflex - automatic

response to a stimulus, sensory neurons, spinal cord, motor neurons

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

Autonomic Nervous System 2. Autonomic Nervous System - carries

impulses from the CNS to internal organs, involuntary controlled by the hypothalamus (BP, stomach movements, body temp, homeostasis)

a. Sympathetic Nervous System -

fight or flight b. Parasympathetic Nervous System –

rest/relaxing

The Autonomic Nervous System

Sensory neurons or“receptors” receive a stimulus from:

eyes - sight ears - hearing nose - smell skin - touch mouth - taste