B2- Keeping Healthy

Protection against Infection
1. Pathogens cause disease. Every pathogen contains antigens
2. White blood cells either engulf & digest the pathogen or release the corresponding antibodies that lock onto the pathogen
3. After an infection, memory cells remain in the body & they can produce the correct antibodies corresponding to the correct pathogen (Immunity)
4. A vaccine is a safe form of a virus
  1. Viruses have side effects that differ in each person
  2. To avoid an epidemic a high percentage of the population have to be vaccinated
5. Antimicrobials are a group of substances that are used to kill microorganisms or slow their growth. They're effective against bacteria, viruses & fungi
6. Antibiotics are a type of anitmicrobials that are effective against bacteria but not viruses
  1. It's important that a course of antibiotics is completed otherwise bacteria can become resistant
7. New drugs have to be tested to make sure they're safe & effective
  1. In an 'open-label' trial everybody knows who gets the new drug
  2. In a 'blind' trial only the doctors know who gets the new drug
  3. In a 'double-b;ind' trial the doctors and patients don't know who has the new drug (only researchers do)
The Heart
1. The heart is a 'double-pump'- as 1 half is pumping oxygenated blood from the lungs to the body, the other half is pumping deoxygenated blood from the body to the lungs
2. Arteries carry blood away from the heart under high pressure
  1. They have very thick walls to withstand pressure
  2. Capillaries link arteries & veins
    1. Walls are 1 cell thick to allow the transfer of substances to & from cells
  3. Veins collect blood and return it to the heart
    1. Walls contain elastic, muscular tissue but are thinner than arteries.. The blood is under low pressure & have valves to prevent backflow of blood
3. Heart disease is caused by a build-up of fatty substances in the arteries
  1. Poor diet, smoking, lack of exercise & genetics are the main causes of heart disease
4. Heart rate is measured by recording pulse rate. This is the number of pulses as blood passes through an artery close to skin
5. Blood pressure measurements record the pressure of blood on the walls of an artery
  1. High blood pressure increases the chance of strokes & heart attacks. Low blood pressure can cause dizziness & fainting
Water Balance
1. Maintaining a constant internal environment is called homeostasis
  1. Homeostasis involves communication by the nervous & hormonal systems
  2. The systems involved in homeostasis are: Receptors (detect change in the environment), Processing centres (receive info & determine how the body will respond), Effectors (produce a response)
2. If the blood plasma is too concentrated, the cells will lose water
  1. If the blood plasma is too dilute, the cells will absorb water & burst
3. The kidneys respond to water concentration in the plasma by releasing dilute or concentrated urine
  1. ADH (Anti Diruetic hormone) keeps water in the body. This tells the body to release a small amount of concentrated urine
    1. Alcohol suppresses the release of ADH, this dehydrates cells
    2. Ecstasy increases ADH production, this drowns cells

Next up

B2- Keeping Healthy

Description

Resource summary

Similar

	Created by lola.jones.x almost 8 years ago