1. The
Nervous
System
KEYWORDS (Write these into your journal book and find the definition as part of your weeks homework)
Gland, Hormone, Impulse, Nervous system, Effector, Stimulus, Receptor, Neurone, Synapse

2. ENDOCRINE SYSTEM STARTER
Name the hormones – Using Figure 2 on page 24 of the Student Book, write down the names of the hormones secreted by the glands shown on the diagram.
Time: 10 minutes
Working Groups: Your choice of 1, 2 or 3

3. STARTER continued Name the hormones – Have you thought of any others?
Time: 10 seconds to add them to your list

4. STARTER answers
Pituitary gland – FSH, LH (stimulates the release and maturity of follicles during menstruation)
Thyroid gland – Thyroxine (regulates the rate of metabolism)
Adrenal gland - corticosteroids and catecholamines including cortisol and adrenaline and small amounts of testosterone (regulates stress levels)
Pancreas – peptides (regulates the production of shorter active digestive enzymes)
Ovary – oestrogen, progesterone and small amounts of testosterone (regulates the growth of eggs and stabilises the growing foetus during pregnancy)
Testis – testosterone (plays a key role in the health and well-being of the man)

5. I AM LEARNING TO understand how the body is controlled
LEARNING OBJECTIVES
I AM LEARNING TO understand how the body is controlled
I WILL LEARN THAT
The nervous system enables humans to react to their surroundings and coordinate their behaviour.
• Receptors detect stimuli which include light, sound, changes in position, chemicals, touch, pressure, pain and temperature.
• Information from receptors passes along cells (neurones) in nerves to the brain. The brain coordinates the response.
• Many processes in the body are coordinated by chemical substances called hormones. Hormones are secreted by glands and are transported to their target organs by the bloodstream.
I CAN
Explain how the body control’s its functions and responses through hormones (chemicals) and nerves (electrical impulses)

6. Identification of the density of nerve endings –
AIM: To investigate the sensitivity of different areas of the skin.
Method:
Working in pairs, one student looks in a different direction, while another student touches them on the back of the hand with either one or two pieces of blunt pencil about 1 cm apart.
The blindfolded student has to say whether it was one point or two points that touched them.
Place a cross on the hand for each point felt.
Results:
Map the density of sensory receptors by drawing it into your book.
Conclusion:
Are the receptors in groups? Or randomly placed? What can you say about the density of the receptors identified?

7. CONTROL SYSTEMS There are two main control systems in your body.
Nervous system – which has two main sections
central or CNS that is made up of the spinal cord and brain and functions to coordinate all actions of the body
peripheral or PNS that is made up of the bodies nerves and functions to connect the CNS to the rest of the body through neurones. PNS is further divided into
somatic or SNS which is associated with the voluntary control of body movements and is made up of all neurones, sense organs, skin, skeletal muscles
Autonomic or ANS which is associated with the involuntary control of body movements such as reflex and controls such things as heart rate, body temperature, digestion etc. The ANS is further divided into
Parasympathetic nervous system works in actions that do not require a fast response (fight or fight response)
Sympathetic nervous system works in actions that do require a fast response (rest and digest response)
Endocrine system – which is a system of glands that release a number of signalling chemicals known as hormones.

8. Say what? NERVOUS SYSTEM CNS PNS SNS ANS Parasympathetic Sympathetic
Nervous system releases electrical impulses that are quick but the effects are short lived and it involves the CNS (either just spinal cord or both spinal cord and brain) messages are carried by neurones
SNS
ANS
Parasympathetic
Sympathetic
Endocrine system releases chemical signals that are slow to react but the effects are long lasting. This does not involve the CNS. Messages are carried by the blood.

9. NERVOUS
SYSTEM

10. Parts of the nervous system
The nervous system is made up of three main parts;
The brain
The spinal cord
Nerve fibres
It detects stimuli such as light, sounds, temperature, pressure, pain and co-ordinates the bodies response.

11. Parts of the nervous system
For example;
If you smell something burning…
Your nose (receptor) detects the stimulus (smell)
Nerve fibres send the message to the brain
Your brain then sends a message to move your body away or to put out the fire!
SIMPLES RIGHT!

12. Lets look at some bits more closely RECEPTORS
Receptors are sensors on the body that detect stimuli
They convert stimuli into electrical signals (messages) called impulses.
Eyes pick up
light waves
through the
retina
Can you think
of any receptors?
Nose picks up
chemical signals
through the
nostrils
Ear picks up
sound waves
through the
eardrum

13. EFFECTORS
An effector is any part of the body that produces the response.
Here are some examples of effectors:
a muscle contracting to move the arm
a muscle squeezing saliva from the salivary gland
a gland releasing a hormone into the blood

14. NERVE FIBRES
Nerve fibres are bundles of nerve cells (neurones) that pass on electrical signals (impulses) to the brain.
From the brain, nerve fibres send impulses to effectors (muscles).

15. NEURONES There are three types of neurones
Sensory neurone – carries impulses from the receptors to the spinal cord.
Relay Neurone – carries impulses to and from the spinal cord and the brain
Motor Neurone – carries impulses from the brain to the effector

16. Multiple-choice quiz Teacher notes
This multiple-choice quiz could be used as a plenary activity to assess students’ understanding of electrical signals. The questions can be skipped through without answering by clicking “next”. Students could be asked to complete the questions in their books and the activity could be concluded by the completion on the IWB.

17. Watch this video on synapses then draw a flow chart of the process
Where two neurones meet, there is a tiny gap called a synapse.
Signals cross this gap using chemicals.
One neurone releases the chemical into the gap.
The chemical diffuses across the gap and makes the next neurone transmit an electrical signal.
Watch this video on synapses then draw a flow chart of the process

18. What is a synapse?
A synapse is a junction between two neurones across which electrical signals pass. The human body contains up to 500 trillion synapses.
presynaptic cell
postsynaptic cell

19. The release of neurotransmitters
When a nerve impulse arrives at the end of one neurone it triggers the release of neurotransmitter molecules from synaptic vesicles.
synaptic vesicle
neurotransmitter molecules

20. Continuing the impulse
The neurotransmitters diffuse across the synaptic cleft and bind with receptors on the next neurone, triggering another impulse.
synaptic cleft
nerve impulse
receptor

21. The stick drop test! METHOD:
Working in pairs, one student holds a metre rule vertically at the zero end, between the thumb and forefinger of another student, so that the 50 cm mark is level with the top of the forefinger.
Without warning, the first student drops the rule and the second student attempts to catch it between the thumb and forefinger, noting the distance on the ruler just above the forefinger.
Repeat several times, so that a mean can be calculated.
Then change around so that everyone gets a turn. Write a report of the experiment.
CONCLUSION AND DISCUSSION:
What was the accuracy of the measurements, the calculation of means and the control of variables?
Identify the parts of the body involved. What senses are being used? Can we train ourselves to react more quickly? Does practice make perfect?
Can we alter reflex actions? – think of a situations where it is possible to alter the automatic response (not dropping a hot object, deliberately breathing more slowly, etc.). Are there some reflex actions over which we have no control?

22. REFLEX ARC
When your body needs to react to something very quickly (to protect itself) it uses a reflex arc (spinal reflex).
Instead of sending impulses from the receptor
Spinal cord brain spinal cord effector
It sends impulses from the receptor
spinal cord effector…Yup it bypasses the brain!

23. ANSWERS
Electrical impulses along neurones, chemical (neurotransmitters) across the synapse.
The microscopic gap between two neurones.
By chemicals called neurotransmitters.
To pass the impulse onto the correct motor neurone.
Glands or muscle that produce the
effect or make a response.

24. The sequence of a reflex arc
Teacher notes
This ordering activity could be used as a plenary or revision exercise on reflex arcs. Mini-whiteboards could be used to make this a whole-class exercise.

25. REFLEX ACTION In bright light In dim light
Radial muscles of the iris relax.
Circular muscles of the iris contract.
Less light enters the eye through the contracted pupil.
Radial muscles of the iris contract.
Circular muscles of the iris relax.
More light enters the eye through the dilated pupil.
The way the iris in our eye adjusts the size of the pupil in response to bright or dim light is also a reflex action.

26. The iris reflex

27. Inside the eye cornea protects eye surface and focuses light rays
hold lens in place
suspensory ligaments
retina
senses light
lens
focuses light on retina
iris
regulates amount of light entering eye
ciliary muscles
change shape of the lens
optic nerve
transmits impulses to the brain

28. REFLEX ACTION

29. PASS THE ZAP
Some volunteers get an A4 sheets on which the names of parts of the reflex pathway are to be written.
The students should then arrange themselves in the correct order.
Using a lightning-shaped zap, each student is to talk through their bit of the process as the impulse (zap) gets passed to them.

30. NERVE PATHWAY… Have a go at completing this worksheet

31. NERVE PATHWAY… answers
SENSE ORGAN/ RECEPTOR
Senses stimuli from our surroundings.
SENSORY NEURONE
Takes impulses from the sense organ to the relay neurone.
SPINAL CORD
Where the relay neurones are found.
RELAY NEURONE
Takes impulses to the brain and from the brain.
EFFECTOR
The muscle that receives the impulse from motor neurone.
BRAIN
Receives impulses from the spinal cord and sends out new impulses.
MOTOR NEURONE
Takes impulses from the relay neurone to the effector.

32. NERVOUS SYSTEM… answers
REFLEX
PROTECTION GIVEN
BLINKING
To eye
COUGHING
Stops us choking
SNEEZING
Removes blockages from the nose
PUPILS CHANGE SIZE
Protects the retina
4a) 37m
55m/s
= 0.67s
4b) RT = d s
= 20m
40m/s
= 0.5s
4c) sensory receptor in eye – sensory neurone – relay neurone - brain – motor neurone - effector
4d) i) brain, ii) takes too long
iii) Stimulus sensory neurone
relay neurone motor neurone
effector

33. Glossary (1/2)
accommodation – The reflex reaction that keeps the lens the right shape to focus light on the retina.
CNS – The central nervous system, consisting of the brain and spinal cord.
iris – The part of the eye that limits the amount of light entering the eye.
lens – The part of the eye that focuses light on the retina.
motor neurone – A neurone that carries electrical impulses from the CNS to muscles and glands.
neurone – A specialized cell that carries electrical impulses.

34. Glossary (2/2)
neurotransmitter – A chemical that diffuses across synapses to continue an impulse in a connecting neurone.
reaction time – The time taken to respond to a stimulus.
reflex – A fast, automatic protective response.
retina – The part of the eye that contains light receptors.
sensory neurone – A neurone that carries electrical impulses from sense organs to the CNS.
synapse – The gap between two connecting neurones.

35. I AM LEARNING TO understand how the body is controlled
LEARNING OBJECTIVES
I AM LEARNING TO understand how the body is controlled
I WILL LEARN THAT
The nervous system enables humans to react to their surroundings and coordinate their behaviour.
• Receptors detect stimuli which include light, sound, changes in position, chemicals, touch, pressure, pain and temperature.
• Information from receptors passes along cells (neurones) in nerves to the brain. The brain coordinates the response.
• Many processes in the body are coordinated by chemical substances called hormones. Hormones are secreted by glands and are transported to their target organs by the bloodstream.
I CAN
Explain how the body control’s its functions and responses through hormones (chemicals) and nerves (electrical impulses)