B1a - Human Biology

- Co-ordination of what happens inside your body, and responses to changes outside your body, rely on hormones and the nervous system.

- The nervous system involves neurones and impulses, which are electrical, except at a synapse.

- A reflex is rapid, automatic response to a stimuli.

- Internally controlled conditions are water content, ion content, tempreture and blood sugar level.

- Hormones are chemicals produced by glands and carried in your bloodstream.

- The menstrual cycle is controlled by 3 hormones... FSH. LH and Oestrogen.

- A healthy diet contains the right balance of different foods.

- Too little or too much food can lead to health and weight problems.

- Too much cholesterol or salt can lead to problems in your blood system.

- Cholesterol is carried in the body by low-density lipo-proteins or high-density lipo-proteins.

- LDLs are bad and HDLs are good.

- Most drugs harm the body. Even those developed to cure disease can have harmful side effects.

- Drugs can be addictive. If you try to stop taking them you may suffer from withdrawal symptoms.

- Microorganisms that cause infection are called 'pathogens'. These include bacteria and viruses.

- The body defends itself by ingesting pathogens, produces antibodies and producing antitoxins.

- We can use antibiotics and vaccination to control infection.

- Some pathogens have developed resistance to anibiotics.