The document discusses how neurons send signals in the brain. It explains that neurons have a cell body, axon, and dendrites. Messages are sent through neurons when an electrical impulse travels down the axon and causes it to release neurotransmitters into the synaptic gap. If the neurotransmitters are received by compatible receptors on the dendrites of the next neuron, they will trigger another electrical impulse along that neuron. Key terms involved are neurotransmitters, action potential, synaptic gap, receptors, and the "lock and key" mechanism by which neurotransmitters are selectively received.

1. Guess today’s topic

2. GCSE Psychology
HOW THE BRAIN SENDS SIGNALS

3. Have you been listening so
far?
What do the following terms mean:
qualitative data,
valid
generalisable
subjective
objective?

4. 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.

5. 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.

6. Different parts of a Neuron

7. 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

8. 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

9. 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.

10. 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)

11. Key terms

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

13. 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.

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