1. OCR Additional Science Brain and Mind
11/06/2018
OCR Additional Science Brain and Mind

2. The Nervous System
11/06/2018
The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors.
Types of receptor:
Light receptors in the eyes
Sound receptors in the ears
Taste receptors on the tongue
Smell receptors in the nose
Touch, pressure and temperature receptors in the skin
Changes of position receptors in the ears (balance)

3. Stimulus Receptor Coordinator Effector Response
Nervous Reactions
11/06/2018
When we react to a stimulus our bodies use the following pattern:
Stimulus Receptor Coordinator Effector Response
For example, consider a man and a camel:
Oh No!
What are the stimulus, receptor, coordinator, effector and response in this situation?

4. Examples of reactions Stimulus Receptor
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Stimulus
Receptor
(i.e. the thing that detects the stimulus)
Effector
(i.e. the thing that will do the reaction)
Response
(i.e. action taken)
Bright light
Sour taste
Losing balance
Sit on a drawing pin

5. Types of nerve cell (“neuron”)
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Nucleus
Axon
Muscle strands (effector)
Fatty sheath
Nerve cells (neurons) are elongated with branched endings to connect to many muscles fibres.
1) Motor neurone
2) Sensory neurone
3) Relay neurone
Impulse
Impulse

6. Words – chemical, synapse, neurone, touch, reabsorbed
Synapses
11/06/2018
Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse (called a “neurotransmitter”). These transmitters are then ________ back into the sensory neurone to be used again. Children have around 1000 trillion synapses whereas adults only have between 100 and 500 trillion.
Words – chemical, synapse, neurone, touch, reabsorbed

7. Conscious actions
11/06/2018
A conscious action is one where the brain makes a considered response. Here’s what happens:
4) The brain decides to move away the hand
3) Here another sensory neurone carries the signal to the brain
5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord…
2) The impulse is carried by SENSORY NEURONES to the spinal chord
1) Receptors in your skin detect a stimulus
6) Which then moves the hand away
Stimulus Receptor Sensory Neurone Coordinator
Motor Neurone Effector Response

8. Reflex actions
11/06/2018
Sometimes conscious action is too slow to prevent harm, e.g…
In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

9. Reflex actions 3. Relay neurone in the spinal chord 2. Sensory neurone
11/06/2018
3. Relay neurone in the spinal chord
2. Sensory neurone
4. Motor neurone
5. Effector
1. Receptor

10. Simple reflexes in humans
11/06/2018
Babies can demonstrate simple reflexes:
Stepping reflex
Startle reflex
Grasping reflex
Rooting reflex
Sucking reflex

11. The Iris Reflex
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When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size.
When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size.

12. Conditioned reflexes - Pavlov’s Dog
11/06/2018
Ivan Pavlov,
I won the Nobel Prize in 1904 and am most famous for investigating “conditioned responses”:
Steak + dog = saliva
Steak + bell + dog = saliva
Bell + dog = saliva

13. Complex Behaviour
11/06/2018
PET scan showing areas “activated” by doing algebra.
When the brain is asked to do certain tasks different areas are “activated”. New experiences cause new neuron pathways to develop, while pathways that are not used are eventually destroyed. This is why we become better at certain tasks when we practice them more often.

14. Feral children
11/06/2018
Task: to find out what “feral children” are, what has caused their condition and what the consequences are.

15. The Cerebral Cortex
11/06/2018
By studying the effects (e.g. memory/sight loss) when different parts of the brain are damaged scientists have been able to identify which parts of the brain control which functions.

16. Other techniques of studying the brain
11/06/2018
1) An electroencephalogram (EEG) is a visual record of the electrical activity generated by neurons in the brain. It works by amplifying and detecting the electrical signals from the brain.
2) Magnetic resonance imaging (MRI) scanning is a new technique that produces images of different cross sections of the brain and uses colours to represent activity.

17. Memory Our memory is divided into two types: short term and long term.
11/06/2018
Our memory is divided into two types: short term and long term.
Short term memory is capable of storing a limited amount of information for a limited amount of time. Long term memory is when more information is stored over a much longer time.
Ways of improving
short term memory,
e.g. a phone number
Ways of improving
long term memory
e.g. exam revision

18. Words – memory, slows, increasing, faster, happy
The Effect of Drugs
11/06/2018
Drugs can have different effects on the nervous system. For example, alcohol _____ reactions down by affecting chemical transmitters in the brain whereas caffeine causes nerve impulses to be sent ______, thereby _______ reaction time.
Serotonin is a neurotransmitter in the central nervous system that is associated with feeling ____. The drug ecstasy blocks the synapses where the serotonin is removed, making the feeling last longer. However, the neurons are harmed in this process and taking ecstasy can lead to long term _____ loss.
Words – memory, slows, increasing, faster, happy