The Nervous System

Function of the Nervous System

1. Receives information about what is happening both inside and outside your body.

2. Directs the way in which your body responds to this information.

3. In addition, your nervous system helps maintain homeostasis.

Structure of the Nervous System

• Nervous system can be broken down into two parts, the and the nervous system.

Central Peripheral

Central Nervous System1. Brain- controls all the functions of your body.

-made of interneurons

Cerebrum- interprets input from the senses, controls movement and carries out complex mental processes (example: learning and remembering).

Cerebellum- coordinates the actions of your muscle (balance).

Central Nervous System con’t

4. Brain Stem- controls your body’s involuntary actions (heart beat).

5. Spinal Cord- link between your brain and the peripheral nervous system.

Peripheral Nervous System

Network of nerves that branch out from the central nervous system and connect the rest of the body.

Structure of a Nerve Cell

• Neuron- the cell that carries the information through your body.

Structure of a Nerve Cell• A neuron has a large cell body that contains

the nucleus.• Dendrites - threadlike extensions on the cell

body that carry impulses toward the neuron’s cell body.

• Axon - carries impulses away from the cell body.

cell body

nucleus

dendrites

axon

Types of Neurons

1. Sensory Neurons- pick up stimuli from the internal or external environment and convert into a nerve impulse.

2. Interneurons- are neurons that carry impulses from one neuron to another.

3. Motor Neurons- sends an impulse to a muscle or gland to react in response.

How an Impulse is Transferred:

• - The junction where one neuron meets another and an impulse is transferred is called a synapse. For a nerve impulse to be carried along at a synapse, it must cross the gap between the axon and the next structure. The axon tips release chemicals that carry the impulse across the gap.

Brains

Frog

Horse Worm

Human