aqa- gcse biology 1a core

-it last 28 days.

-F.S.H matures the egg.

-L.H. release's the egg from the ovaries.

-Oestrogen stimulates the production of L.H.

-Progesterone maintaines the linning of the uterus.

- Pathogens: are microorganisms that cause infectious disease. Bacteria and viruses are the main pathogens.

- diseases caused by bacteria include: food poisoning, cholera, typhoid and whooping cough.

- diseases caused by viruses include: infulenza, cold, measles, mumps, rubella, chicken pox and AIDS.

- White blood cells: ingest pathogens and digest them, produce antibodies to destry pathogens and produce anti toxins that neutrolise the toxins released by pathogens.

- vaccines contain: live pathogens treated to make them harmless, harmless fragments of the pathogen, toxins produced by pathogens and dead pathogens.

- Nicotine: is the addictive drug found in tobacco, it reaches the brain within 20 seconds.

- Tobacco: around 114,000 people die every year as a result of smoke realted ilnesses.

- Carcinogens: are substances that cause cancer, tobacco contains many carcinogens such as tar.

- Smoking: increases the risk of throat, lung and mouth cancer.

- Alcohol: is made from 200% ethanol and classed as a depresent. which means it slows down signals inthe nerves and the brain.

- Long term effects: include damage to the liver and brain. Alcohol is also addictive and can cause some weight gain.

- Alcohol and Tobacco are legal recreational drugs.

- heroin and cocaine are illegal recreational drugs.

- Heroin and cocaine are both addictive hard drugs.

- Receptors: Skin, Nose, Eyes, Tongue and Ears. These are sensitive towards Touch, pressure, pain, tempreture, chemicals, light, sound and sense of direction.

- Effectors: a muscle contracting to move the arm, a muscle squeezing saliva from the salivary gland, a gland releasing hormones into the blood.

- Sensory neurone: carries signals from the receptors to the spinal cord and brain.

- Relay neurone: carries signals from one part of the C.N.S. to another.

- Motor neurone: carries signals from the C.N.S to the effectors.

- Synapse: is where chemical reactions take place.

- Fibre: good source of energy, found in food such as potatoes and bread.

- Fats: needed to make cell membranes and to insulate our bodies, found in foods such as cheese and butter.

- Growth: need to help to repair muscles, found in food such as meat and fish.

- Vitamins: we need vitamins to helpimprove our immune system, found in food such as fruit and vegtables.

- Metabolic rate: in which chemical reactions take place varies due to factors such as: age, gender, the ratio of fat to muscle, the amount of excersise they take part in and genetic traits.

- Not eating enough food: irregular periods in women, reduced ressitance towards infection and deficency diseases.