Biology B2

Biology B2

Balancing water
1. correct level for cell activity
2. kidneys help balance substances in the body
  1. filter out small molecules like water, sugar, salt and waste
  2. reabsorb various things
    1. whatever isn't is then made urine which is excreted by bladder
Heart and circulatory
1. Arteries
  1. Carry blood away from the heart to body cells
    1. High pressure so thick, strong and elastic walls are used
2. Veins
  1. Carry blood back to the heart
    1. Lower pressure so thinner walls
    2. Bigger lumen to help blood flow more easily
3. Capillaries
  1. carry blood really close to every cell
    1. thin wall so substances can diffuse in and out
    2. very small lumen
Drug Trials
1. Tested in a lab (1st)
  1. Tested on human cells
    1. cannot recreate the conditions of a human body
    2. Tested on live mammals to check for harmful substances
      1. stopped if drug fails or is too harmful
2. tested on humans (2nd)
  1. tested on healthy people first to check for side effects
    1. Placebos are used (fake drugs)
    2. blind trials, double-blind and open-label trials
Antimicrobials
1. chemicals that inhibit the growth of microrganisms or kill them
  1. EG - Antibiotics/Penicillin
    1. important to finish entire course
      1. increases risk of antibiotic resistance bacteria coming back
2. Microorgasnisms can become resitant (they evolve)
  1. random mutation in their DNA
Diseases
1. Bacteria, Virus and Fungi
  1. Reproduces quickly - making copies of themselves
    1. Need warm, moist conditions like intestines and nutrients
  2. Need other cells to reproduce
    1. Makes copies of themselves
2. Immune System
  1. White Blood Cells
    1. Located the foreign microorganism
      1. Digests it and then memories it in case it comes back
        White blood cell divides to produce more antigens so it can fight the infection
    2. Antibodies help locate the foreign cell and mark it
3. Vaccinations
  1. Injecting a dead or inactive microorganism
    1. Body can produce antibodies to attack them and create antigens (memory cells)
      1. If it appears again, the body can fight it off quicker
  2. Less chance of epidemics spreading if more of the population is vaccinated

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	Created by Sysode almost 11 years ago