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GCSE Psychology

HOW THE BRAIN SENDS SIGNALS

Have you been listening so far?

What do the following terms mean:

qualitative data,

valid

generalisable

subjective

objective?

Learning outcomes To learn what a neuron is and what it is made up of.

To investigate how messages are sent around the brain using neurotransmitters.

Neuron You will need to know the basic structure of a Neuron and what it is for.

◦ It is a cell in the nervous system that processes and sends information within the body, using chemical and electrical signals.

◦ The activity of neurons is central to how the brain and body work. ◦ Senory Neurons receive messages, Touch, light and sound. ◦ Motor Neurons about muscle and movement.

Respond to stimuli from the environment or inside the body and communicate with the nervous system.

Brain and the spinal column make up the central nervous system. (CNS).

◦ CNS processes information processes information and sends to the relevant parts of the body to act upon.

Different parts of a Neuron

A neuron has four important features.

Cell Body ◦ The cells life support centre.

Terminal Buttons◦ Form junctions with other cells

Axon◦ Passes messages away from the cell body to other neurons, muscles and

glands.

Dendrites◦ Receive messages from other cells

In groups of 4 Using the key functions of a Neuron I would like to see what role you would play in passing this message on.

Cell Body ◦ Creates a message, can be any message.

Terminal Buttons

Axon

Dendrites

How brain messages are sent using neurons

Messages in the brain are sent using electrical impulses and chemicals that are called Neurotransmitters.

Step 1◦ An electrical impulse is triggered from the cell of one neuron then travels

down the axon to the end. The impulse is called action potential.

Step 2◦ When te impulse gets to the end of the axon it releases a chemical, called a

neurotransmitter, that is found in the terminal buttons at the end of the axon.

Step 3◦ The neurotransmitter has to cross a gap, called the synapse or Synaptic gap,

to get to the Dendrites of the next neuron to continue the message.

Step 4◦ The neurotransmitter, released impulse goes into the gap – where it could be

taken up by the dendrites or could be lost.

Step 5◦ If the receptors at the dendrites of the next neuron are ‘suitable’ to receive the

neurotransmitter that is in the gap, then the chemical get picked up.

Step 6 ◦ The neurotransmitter sets off an electrical signal (by changing the chemical

balance at the receptor) and then it drops back into the synaptic gap where it can be taken back up and used again.

Step 7◦ The change in chemical balance (from the receptors) triggers an electrical

impulse from the cell body, which travels down the axon…(Step1)

Key terms

What is a neuron?•How are brain messages sent using neurons?

Explaining Lock and key. Receptors at a dendrite will be a shape (‘lock’) to take up only a certain neurotransmitter (‘key’) and all other neurotransmitters will not be taken up.

When someone takes drugs, one effect of the drug is to fill the ‘lock’ of the neuron so that when the neurotransmitter message arrives in the gap, it can fit the recptor (which is already full). This means that the message is stopped or ‘blocked’.

Pain killers can block the message of pain in this way.

‘Lock’ and ‘key’ Complete questions 1 and 2 from the bottom of page 63.