sense organs such as the eye, ear, nose, tongue and skin
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What are stimuli?
Light, sound, sent, flavour, heat
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What does a stimuli do?
Stimulates the receptor and electrical impulses which are passed along by neurons (nerve cells).
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What is the central nervous system?
The brain and spinal chord
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What is the function of the sensory neuron?
Carry impulses form receptors to the CNS
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What s the function of the motor neuron?
Carry impulses from the CNS to the effector organs which can be the muscles or the glands.
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How do the effector organs respond to the impulses carried by the motor neuron?
The muscles contract. The glands respond by secreting chemicals.
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Describe the reflex arc in 7 stages
1. receptor detects stimuli 2. Sensory neuron transmit impulse to the CNS 3. Arrive at junction known as the synapse 4. Chemicals transmit impulse to relay neuron 5. Motor neuron is stimulated 6. Impulses meet effector 7. Response
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What are the hormones involved in the menstrual cycle?
1. Follicle stimulating hormone 2. made in the pituitary glands 3. Causes egg to mature 4. stimulates the production of oestrogen
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What is the function of Oestrogen?
1. Produced in the ovaries 2. Inhibits the production of FSH 3. Stimulates the production of LH 4. Stimulates the womb lining in preparation to receive the fertilised egg.
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What is the function of LH?
Luteinising Hormone 1. Produced by the pituitary gland 2. Stimulates the matured egg to be released. 3. A process known as ovulation.
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How long in the menstrual cycle?
28 days
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How many days into the cycle does ovualation occur?
14 days
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What can contraceptive pills contain?
Oestrogen and progesterone
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why are some pills prooestrogen only?
This is because progestrone-only pills have fewer side effects.
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What does a contraceptive pill do?
Prevents the production of FSH so no eggs mature
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What is given to a women who cannot produce eggs?
This is known as fertility treatment and the women is given LH and FSH
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What happens in fertility treatment?
FSH causes the egg to mature LH stimulates the release of the egg
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What are the advantages of fertility treatment?
1. C -Reduced poverty and reducing size of family 2. C - Allows women to plan their pregnancies 3. Can help infertile couples
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What are the disadvantages of fertility treatment?
1. Contraceptive pill can cause side effects 2. Religious reasons 3. IVF is expensive 3.IVF is unethical 4. Extra embryos can destroyed or stored
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What are the internatl conditions that need to be controlled?
1. Water content 2. ion content 3. blood sugar levels 4. temperature
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How is the level of sugar in our blood controlled?
By the pancreas which produces insulin
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Why is it important to control out body temperature?
Temperatures should be kept constant otherwise the enzymes in our body will not work properly
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What are plants sensitive to?
light, gravity and moisture
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What is photoropism
The response when plant shoots grow towards the light
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What is gravitropism?
The response when plant shoots grown towards gravity
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What is auxin?
A hormone which control phototropism and gravitropism
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What happens when there is an unequal distribution of auxin?
This causes unequal growth which causes the bending of shoot or root.
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What can plant growth hormones be used for?
1. weed killers 2. stimulate growth of root
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How are hormones used in women?
1. Contraceptive pill for unwanted pregnancies 2. Help them to become pregnant 3. Older woman have babies
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How are hormones used in plants?
1. weed killers 2. Cuttings can be taken from plants, hormones are used to encourage roots to grow before the cutting is planted 3. fruit to ripen 4. They can damage the environment
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