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. STARTER. ENDOCRINE 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
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
Name the hormones – Have you thought of any others?
Time: 10 seconds to add them to your list
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)
There are two main control systems in your body.
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
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.
The nervous system is made up of three main parts;
It detects stimuli such as light, sounds, temperature, pressure, pain and co-ordinates the bodies response.
If you smell something burning…
Eyes pick up
Can you think
of any receptors?
Nose picks up
Ear picks up
An effector is any part of the body that produces the response.
Here are some examples of effectors:
There are three types of neurones
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
A synapse is a junction between two neurones across which electrical signals pass. The human body contains up to 500 trillion synapses.
When a nerve impulse arrives at the end of one neurone it triggers the release of neurotransmitter molecules from synaptic vesicles.
The neurotransmitters diffuse across the synaptic cleft and bind with receptors on the next neurone, triggering another impulse.
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?
Spinal cord brain spinal cord effector
spinal cordeffector…Yup it bypasses the brain!
effect or make a response.
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.
protects eye surface and focuses light rays
hold lens in place
focuses lighton retina
regulates amountof light entering eye
transmits impulses to the brain
change shape of the lens
SENSE ORGAN/ RECEPTOR
Senses stimuli from our surroundings.
Takes impulses from the sense organ to the relay neurone.
Where the relay neurones are found.
Takes impulses to the brain and from the brain.
The muscle that receives the impulse from motor neurone.
Receives impulses from the spinal cord and sends out new impulses.
Takes impulses from the relay neurone to the effector.
4c) sensory receptor in eye – sensory neurone – relay neurone - brain – motor neurone - effector
4b) RT = ds
4d) i) brain, ii) takes too long
iii) Stimulussensory neurone
relay neuronemotor neurone