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  • Created by: niki
  • Created on: 03-04-11 16:39

> hormones, secreted by special glands, are chemicals that help control and co-ordinate processes in your body

> the nervous system uses electrical impulses to enable you to react to your surroundings and co-ordinate what you do

> cells called receptors detect stimuli (changes in the environment)

> impulses from receptors pass along sensory neurones to the brain. Impulses are sent from the brain to the effector organs along motor neurones

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responding to change

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> some responses to stimuli are automatic and rapid and are called reflex actions

> reflex actions run everyday bodily functions and help you to avoid danger

> stimulas -> sensory neurone-> synapse-> relay neurone-> synapse-> motor neurone-> motor end plate (muscle or gland)

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reflex actions

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> hormones control the release of an egg from the ovary and the build up of the lining of the womb in the menstrual cycle

> the main hormones involved are FSH and LH from the pituitary gland and the oestrogen from the ovary

> FSH: secreted by the pituitary gland. It makes eggs mature in the ovaries and also stimulates the ovaries to produce oestrogen

> OESTROGEN: made and secreted by the ovaries. It stimulates the lining of the womb to build up ready for pregnancy. It also stimulates the pituitary gland to make LH

>LH: secreted by the pituitary gland. It stimulates the release of a mature egg from one of the ovaries in th emiddle of the menstrual cycle.

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the menstrual cycle

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> hormones can be used to control fertility

> oral contraceptives contain hormones, which stop FSH production so no eggs mature

>FSH can be used as a fertility drug for women, to stimulate eggs to mature in their ovaries. These eggs may be used in IVF treatment

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the artificial control of fertility

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> humans need to maintain a constant internal environment, controlling levels of water, ions, blood sugar and temperature

> homeostasis is the result of the coordination of your nervous system, your hormones and your body organs

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controlling conditions

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> most people eat a varied diet, which includes everyhting needed to keep the body healthy

> different people need different amounts of energy

> the metabolic rate varies from person to person

>the less exercise you take, the less food you need

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diet and exercise

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> if you take in more energy than you use, you will store the excess as fat

> obese people have more health problems than people of normal weight

> people who do not have enough to eat can develop serious health problems

> BMI= weight / (height)squared

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weight problems

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>fast food often contains high proportions of fat and/or salt

> cholesterol is made in the liver and found in the blood. High cholesterol levels have been linked to heart disease

> the level and type of cholesterol in your blood is influenced by the type of fat you eat

> too much salt in the diet can lead to raised blood pressure in about a third of the population

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fast food

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>drugs change the chemical processes in your body, so you may become addicted to them

> alcohol, tobacco and illegal drugs may harm your body

> smoking cannabis may cause psychological problems

> hard drugs, such as cocaine and heroin, are very addictive and can cause serious health problems

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> many recreational drugs affect the brain and nervous system

> some recreational drugs are legal and others are illegal

> the overall impact of legal drugs on health is much greater than illegal drugs because more people use them

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legal and illegal drugs

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> legal recreation drugs

  • ethanol (alcohol)
  • nicotine (cigarette smoke)
  • caffeine (coffe, tea, cola, etc)

> illegal recreational drugs

  • cannabis
  • cocaine
  • heroin
  • ectasy
  • LSD
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legal and illegal recreation drugs

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> alcohol affects your nervous system by slowing down your reactions

> alcohol can lead to loss of self control, unconsciousness, coma and death

> alcohol can cause damage to your liver and brain

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>tobacco smoke contains substances which can help to cause lung cancer, lung diseases such as emphysema and bronchitis, and diseases of the heart and blood vessels

> tobacco smoke contains carbon monoxide, which reduces the oxygen carrying capacity of the blood. In pregnant women this can deprive the foetus of oxygen and can lead to a low birth mass or death

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smoking and health

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