Biology Unit 2

Microorganisms and disease
1. Symptoms can be caused by cell damage or by toxins
2. Malaria symptoms caused by cell damage
3. E-coli releases toxins
4. Microorganisms reproduce quickly inside the body
5. Bacteria make copies of themselves
6. Viruses need other cells to reproduce
The immune system
1. Fights of invading microbes
2. Responses always involve white blood cells
3. White blood cells can engulf and digest the microorganisms
4. Antibodies recognise foreign microorganisms
  1. Sends out correct antibody to fight the antigen on the microbe
5. Antibodies are proteins specific to a particular antigen
Vaccination
1. Use a safe version of a dangerous microorganism
2. First infection- takes a while for white blood cells to respond
3. Immunisation- infecting with dead or inactive microorganisms
4. Memory cells remember antigens
5. If live microorganisms appear AGAIN the body can make antibodies more quickly to kill the microorganism more quickly
6. Prevents epidemics
7. Have different effects on different people
Antimicrobials
1. Can inhibit or kill bacteria, fungi and viruses
2. Antibiotics are one type
3. Clear up infections
4. Microorganisms can evolve and become resistant
5. Always finish antibiotic course
  1. More courses of antibiotic- leaves only the resistant microbes
Drug Trials
1. Tested in a lab first
2. developed using lab grown human cells
  1. Can't predict how it will effect a living human
3. Test on humans = clinical trial
  1. Blind trial- patients don't know if they have the placebo or drug
4. First on healthy volunteers
  1. Then ill people
5. Placebo's are used
  1. Not ethical on very ill patients
6. Double blind trial- even scientist doesn't know what they are giving the patient
7. Open label trials- all parties are aware of what is being used
The circulatory system
1. Arteries- blood away from the heart- thick walls for the high pressure
2. Veins- back to heart- thin walls big lumen
3. Capillaries- one cell thick
heart rate and blood pressure
1. Pulse rate used to measure your heart rate
2. Heart rate in BPM
3. Blood pressure- the pressure of blood against artery wall
  1. Two values
    1. HIgher= pressure when heart contracts
    2. Lower= pressure when heart relaxes
  2. Average healthy lower- 60-100 BPM
4. High blood pressure increases risk of heart disease
  1. Build up of fatty deposits increase blood pressure
    1. if deposit breaks through inner lining of the artery a blood clot could form around it
      1. if a coronary artery becomes blocked it cuts off the blood and oxygen supply to part of the heart and this part dies.
Heart disease
1. Poor diet
  1. Cholesterol makes most of fatty deposits
  2. High blood cholesterol is linked to eating foods with high saturated fats e.g. fatty meats and cheese
  3. Salt increases risk- it increases blood pressure
2. Smoking
  1. carbon monoxide and nicotine increase risk
    1. CO reduces amount of oxygen in the blood
      1. If the heart doesn't get enough oxygen- heart attack
3. Stress
  1. + BP = +risk of heart disease
4. Illegal drugs
  1. + heart rate =+ risk of heart disease
    1. Same as excessive alcohol
Homeostasis
1. Maintaining a constant internal environment
Controlling water content
1. Inputs- water can be gained from drink, food and respiration
2. Outputs- sweating, breathing, faeces and urine
3. Kidneys help balance substances in the body
  1. Filter small molecules from the blood
    1. Reabsorb- all the sugar and as much salt and water as the body requires
4. Urine isn't always the same
  1. External temperature
    1. Effects how much you sweat- more sweat= water loss so kidneys will reabsorb more water back into the blood
      1. Small amount of concentrated urine
  2. Exercise- makes you hotter- sweat to cool down
  3. Intake of fluids and salts- eating too much salt/not enough water=concentrated small amount of urine

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Biology Unit 2

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	Created by anna.mat1997 about 11 years ago