* The nervous system is made up of the central nervous system (CNS) and the peripheral nervous system.
* Receptor cells react to external stimuli.
* Synapses carry electrical impulses between neurones.
* A reflex action is carried out automatically by the body and involves sensory, relay and motor neurones.
* The body needs to control internal functions: water content, ion content, body temperature and blood sugar level.
* The glands produce hormones which reach their target area via the bloodstream.
* The menstrual cycle involves the hormones FSH, LH and oestrogen.
* Oral contraceptives contain either oestrogen or progesterone.
* In Vitro Fertilisation (IVF) involves giving a woman FSH and LH so that her eggs mature. The eggs are then fertilised outside the body.
* Auxins are a plant hormone and control root and shoot growth.
*Weed killers and growth hormones are used by humans to control plant growth.
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Test it: Nerves and Hormones
1. IVF involves giving particular hormones to a woman in order to stimulate her eggs into maturing. Which two?
a) FH
b) LSH
c) oestrogen
2. When there are changes in the surrounding environment the human body responds in a certain way. Put these sentences in the correct order from 1 to 4.
Electrical impulses move along neurones.
The body detects a stimulus.
Muscles cause a response.
Receptors are stimulated.
3. The menstrual cycle is where an egg is released on a monthly basis so that it can be fertilised. Match the function to the body part:
hormones cause its lining to thicken embryo
egg production pituitary gland
releases FSH ovary
formed once the egg is fertilised and starts dividing womb
4. A gardener decided to grow a plant in a pot and placed it on a window sill. However, the wind knocked the plant on its side and it is left like that in the dark for two days. When the gardener finds the plant the shoots have started to grow upwards. Explain why.
ANSWERS
- a) FH and b) LSH
2. The body detects a stimulus.
Receptors are stimulated.
Electrical impulses move along neurones.
Muscles cause a response.
3. hormones cause its lining to thicken ? womb
egg production ? ovary
releases FSH ? pituitary gland
formed once the egg is fertilised and starts dividing ? embryo
4. Due to negative gravitropism. Shoots grow against gravity because more auxins are produced on the lower side of the stem causing it to grow up vertically.