1The Nervous System

Functions of the Nervous System

1. Control center for all body activities2. Responds and adapts to changes that occur both

inside and outside the body(Ex: pain, temperature, pregnancy)

Sensory monitors internal & external environmentthrough presence of receptors

Integration interpretation of sensory information(information processing); complex (higher order)functionsMotor response to information processed throughstimulation of effectors

muscle contraction glandular secretion

Functions of the Nervous System

Two Anatomical Divisions Central nervous system (CNS)

Brain Spinal cord

Peripheral nervous system (PNS) All the neural tissue outside CNS Afferent division (sensory input) Efferent division (motor output)

Somatic nervous system Autonomic nervous system

General Organization of the nervoussystem

General Organization of the nervoussystem

THE CENTRAL NERVOUS SYSTEM

2Brain : a mass of 100billion neuronslocated inside theskull

-Learning occurs asmore and strongerconnections aremade betweenneurons

Central Nervous System Anatomy of the BrainCerebrum : largest partof human brain

- Responsible for:- Thought- Language- Senses- Memory- Voluntarymovement

Retrieval of a Memory

A memory is not asnapshot stored in thebrain it must be puttogether frominformation stored invarious parts of thebrain

Cerebellum : at baseof brain

-Responsible for:- Musclecoordination- Balance- Posture

Anatomy of the Brain

Brain Stem :connects brain tospinal cord

-Responsible for:- Breathing- Swallowing- Heartbeat- Blood pressure

Anatomy of the BrainSpinal Cord : Column of nervesfrom brain to tailbone protected by vertebrae of spine

- Responsible for:- Conducting impulsesbetween the brain and the restof the body

*Impulses may travel as fast at268 miles/hr

Central Nervous System

3Central Nervous SystemNeurons : microscopicnerve cells that makeup the brain, spinalcord, and nerves

- 30,000 neurons can fiton a pinhead

Anatomy of a Neuron

Each neuron contains:- Cell body with nucleus- Dendrites : fibers thatreceive messages fromother neurons

- Axons : fibers that sendmessages to otherneurons

Neurons do NOT touch;there is a gap betweenthem called a synapse

Messages are sentacross the synapses byspecial chemicals calledneurotransmitters

Anatomy of a Neuron Communication Between Neurons

- The use ofneurotransmitterscauses an electricalcurrent

There is enough electricalcurrent in the brain topower a flashlight

Brain TeaserIf you were running a race, and you passed theperson in 2nd place, what place would you be innow?

Second

Brain TeaserA H I M N O T U V W

Which of the letters above does not belong with therest?

N It is not a mirror-image of itself

4THE PERIPHERAL NERVOUS SYSTEM

Peripheral Nervous System

Nerves : visiblebundles of axons anddendrites that extendfrom the brain andspinal cord to all otherparts of the body

-Responsibilities:- Sensory nerves - carrymessages from bodyto brain (pain,pressure,temperature)

- Motor nerves carrymessages from brainto body to respond

Peripheral Nervous System Terminology

Input: sensory = sensory input Receptors monitor changes Changes called stimuli (sing., stimulus) Information sent by afferent nerves

Integration Info processed Decision made about what should be done

Output: motor =motor output Effector organs (muscles or glands) activated Effected by efferent nerves

Remember the difference between the English words affect andeffect

Terminology, continued

The music affected her deeply.

(Something is experienced: sensory)

His protests had no effect.

(Something is done or not done: motor)

Simplified

5END