Body Control Systems

Year 9 Science

Introduction You are made of about 100 trillion cells

These need to behave in a co-ordinated manner for you to function effectively

In the human body their are two major systems that do this:

The Nervous System Consists of tissues that

conduct nerve impulses

Impulses travel at high speed

Generally brings about fast, short term change

The Endocrine System Consists of glands that

produce chemical messages (Hormones)

Hormones travel through the blood stream

Generally brings about slow, long term change

The Nervous System

The structure of the nervous system

The Nervous system is made up of 2 parts

The Central Nervous System (CNS)

The brain & Spinal cord

The Peripheral Nervous system (PNS)

All the other bits

Our Nervous system is our interface with the outside world

Parts of the Nervous System

It is made of of 4 types of neurone (we will deal with 3)

1. Brain Cells information processors

2. Sensory neurones detect the outside world and send signals to the CNS

3. Motor Neurones These receive signals form the CNS & pass them on to

muscles and glands

The Basic Structure of the Neurone

All Neurones have the same basic structures:

A cell body Dendrites

Extensions from the cell body that receive information.

Axon This extension send

information on NB: Neurones are the oldest and longest cells in your body. You have many of the same neurones for your whole life.

Sensory neurons receive or detect information from specialised cells which it sends to the CNS for processing

In the CNS Information is processed.

From the CNS commands are sent to motor neurones in the PNS which activates muscles and glands.

REMEMBER: Nerves carry signals in only one direction

The Peripheral Nervous system

Sensory Neurones

Motor Neurones

The Central Nervous System(Brain & Spinal Cord)

Remember: Information travels through the neurones as

an electrical impulse.

Information is passed between neurones as chemical messages.

Motor Neurone

Sensory Neurone

Brain Cell