kid knees

• describe the process of ultrafiltration:

  1. blood from the renal artery enters the afferent arteriole at low pressure due to a wide lumen
  2. high hydrostatic pressure is produced forcing substances such as urea and ions to leave via the capillaries called the glomerulus
  3. they leave by the gaps between the endothelial cells, podocytes and basement membrane
  4. blood then leaves at high pressure through the efferent arteriole
• describe the process of selective reabsorption:


  1. Na+ is actively pumped out of the epithelium cell into the blood stream using a sodium/potassium pump, the ions pass through the basement membrane and capillary endothelium
  2. this creates a concentration gradient between the fitrate and the cell
  3. so Na+ diffuses down the concentration gradient and glucose/amino acids move into the cell with Na+ using a co-transport protein
  4. glucose then diffuses into the blood via facilitated diffusion
• describe the process within the loop of Henle:


  1. the loop of Henle acts as a counter current multiplier
  2. Na+ ions are actively transported out of the ascending limb to lower the water potential in the interstitial fluid
  3. the ascending limb is impermeable to water so water only moves out of the descending limb via osmosis into the area of low water potential
  4. water then enters the capillaries
• distal convoluted tubule and collecting duct


  water naturally moves out
• whats the 4 step process in which water is reabsorbed by kindeys:

  1. ultrafiltration
  2. selective reabsorbtion
  3. loop of Henle
  4. distal convulated tubule and collecting
  5. duct