June 2022 paper

• state functions of Kidney

  1. excretion
  2. reabsorption of water/reabsorption of ions
  3. electrolyte balance
  4. blood pressure regulation
  5. osmoregulation/salt water balance/maintain blood water level
• describe how water is reabsorbed from collecting duct

  • down concentration gradient
  • by osmosis
  • through aquaporins
  • under influence of ADH
  • which causes permeability of collecting duct walls to water
• give one reason why there is no protein in urine

  molecules too large to be filtered/pass through basement membrane/through glomerulus
• which process do WBC use to ingest bacteria

  endocytosis
• phagocytic cels contain many mitochondra explain why

  • mitochondria produces ATP
  • by aerobic respiration
  • cuz phagocytosis needs energy
• explain how the destruction of alveoli walls affects gaseous exchange

  • reduces SA
  • so less diffusion/gaseous exchange
• where is the location of the sinoatrial node

  right atrium
• myogenic

  heart muscle CONTRACTS on its own without any stimulation from BRAIN/NERVES
• describe the function of coronary arteries

  supply/carry oxygen/oxygenated blood to heart muscle/wall of ventricles/atria
• explain 2 advantages of using blood vessel tissue taken from patient rather than tissue taken from a donor

  1. same blood group so less risk of cancer, immune system will not be weakened/less risk of infections. no need for immunosupressants.
  2. Quicker/no need to wait. donors needs to be of the same blood group/tissue type. only the patient has risk associated with surgery to obtain vein tissue
• explain importance of residual air

  • residual air = air left in the lungs before inhaling/after exhaling
  • stops lungs collapsing/ prevents alveoli sticking together/keeps alveoli open
  • which would reduce gaseous exchange
  • would be difficult to open up alveoli after they had stuck together
• tidal volume

  volume of air inhaled in one breath
• tidal volume of air travels through trachea into the bronchus and then into bronchioles then there wont be gaseous exchange
• alveoli cells make substance called surfactant to prevent alveoli from collapsing