Function of nephrons

• What is ultrafiltration 


  Filtering substances out of the blood at the molecular level
• Where is the glomerulus supplied with blood from 


  By the wide afferent arteriole from the renal artery
• What does the blood leave the glomerulus by

  The narrow efferent arteriole
• What does the wide afferent and narrow efferent arteriolar cause

  Considerable hydrostatic pressure in the glomerulus
• What does the pressure in the glomerulus cause

  The blood to be forced out of the capillary
• What lies adjacent to the capillary walls of the glomerulus

  The basement membrane
• What does the basement membrane do

  acts as a sieve and stops red blood cells and large plasma proteins from passing through
• What is the basemen membrane made of

  Network of collagen and glycoproteins
• What specialised cells are in the wall of the bowman’s capsule 


  Podocytes which act another filter
• What are the extensions of the podocytes called

  Pedicels
• What do the pedicels Do

  They wrap around the capillaries to stop any red blood cells or plasma proteins that got through the basement membrane from going into the capsule
• What is the process of ultrafiltration

  1. blood is forced out of the capillaries between the gaps In the endothelium membrane
  2. the basement membrane lies next to the capillary wall to stop any red blood cells and large plasma protein
  3. there are specialised cells called podocytes to filter any red blood cells or large plasma proteins that managed to get through
• What does the filtrate that enters the capsules contain

  Glucose, water, urea, salts (sodium and chloride), amino acids, vitamins and hormones
• What is the order of selective reabsorption

  Proximal convoluted tubule

  loop of Henel

  distal convoluted tubule

  collecting duct
• What is does the proximal convoluted tubule do

  Major reabsorption of most things
• How are most things in the proximal convoluted tubule reabsorbed

  by active transport
• Why does proximal convoluted tubule not reply on diffusion 


  Since the substances may reach equilibrium and we want everything back into the blood
• What do the cells lining the proximal convoluted tubule have adaptions for

  Covered with microvillI to increase SA for things to be reabsorbed And many mitochondria to provide atp for active transport
• What is the loop of Henle


  Reabsorption of water and salt ions
• the process of the loop of Henle

  1. when the filtarte enters the loop of Henle it is isotonic (same conc) as the tissue fluid
  2. first thing that gets removed is water by osmosis so as we move down the descending limb the ion conc of sodium and chloride increase.
  3. at the hairpin bend the filtrate has reached hypertonic point (high conc of salts)
  4. the first section of the ascending limb has higher conc of salts inside compared to outside so they can diffuse out easily.
  5. as we go up the ascending limb the conc of salt decarease and it reached isotonic so the salts are actively transported out
• What is distal convoluted tubule 


  Reabsorption subject to body needs
• When does distal convoluted tubule process occur

  Of the body needs more salt or water it will reabsorb it by active transport, chloride by diffusion sodium by active transport and water by osmosis
• What does the collecting duct do

  Reabsorbs water with the help of ADH. The more ADH the more water reabsorption