Kidney and Osmoregulation

Kidney and Osmoregulation

1. Osmoconformers

   • Osmoconformers are animals that have internal tissues that have virtually the same solute concentration as their environment. They are iso-osmotic to the water of their surroundings.
   • Osmoregulators
     • Osmoregulators are animals whose internal tissues have a different solute concentration compared with their environment. Have mechanisms that regulate water balance .Animals

2. The Malpighian tubule system in insects

   • Carry out osmoregulation and removal of nitrogenous wastes
     • Insects have an open circulatory stem -blood is outside the blood vessels . Malpighian tubules lie in pools of blood. Tubes have a closing on(distal end) and a closing on the proximal end.
       •  Molecular components of blood enter the distal end (undergo selective reabsorption) . Toxins, excess water and Nitrogenous waste remain in the tubule. Useful substances go to the pool of blood. The nitrogenous waste (uric acid) and excess water empties from proximal end into the gut.  Waste is then eliminated with faeces.

3. Difference between Blood in Renal Artery and Renal Vein

   • Renal Vein
     • Lower Urea
     • Lower salt ions
     • Same glucose and amino acids
     • Lower Water

4. Ultrafiltration

   • Glomerulus
     • Filters various substances from the blood , bed of capillaries
     • Fenstrations (tiny slits) open when blood p. increase
       • The increase blood pressure comes from the efferent arteriole (smaller diameter than aa)which drains blood from glomerulus. Connecting a large diameter to a small diameter increases blood pressure.
   • Bowmans Capsule (BC)
     • Surrounds the glomerulus
       • Afferent arteriole (aa) leads to glomerulus from BC

5. Selective Reabsorption

   • Proximal Convulated Tubule
     • Active Transport of useful substances
       • Salt Ions (AT) ,Water (O) , Glucose (AT)
     • Wall- 1 cell thick , microvilli (increase surface area), lumen (filtrate flows here)

6. Loop of Henle

   • Medulla - Hypertoni conditions maintenance
   • Permeable 2 Water Impermeable 2 Salt= DL
     • Impermeable to Water Permeable to Salt= AL 1st
       • Salt ions are pumped out and enter the intercellular fluid . Water relatively Hyptonic - High Water content
   • Longer loop of H= Water conservation

7. ADH in Collecting duct

   • Filtrate is dilute urine
     • Collecting duct permeable to water
       • P=depends on ADH
   • ADH from prosetrior lobe of pituatary gland
     • If ADH present, more permeable to water and water moves by osmosis out of collecting duct and into medulla , to bloodstream
     • If ADH not present, the collecting duct impermeable to water ,water stay in collecting duct,dilute urine

8. Dehydration and Overhydration

   • D= Sleepiness ,Constipation ,Dry mouth and Skin , Dizziness and headache
   • O= Blurred vision ,nausea and vomitting , Change in behaviour, Muscle cramps

9. Treatment of Kidney Failure

   • Haemodyalisis= blood pumped into a device with large surface area of membrane
     • Dialysate (other side) same as patient blood+no urea
       • Urea diffuse through the membrane and so urea leave patient blood. It could also have a transplant (immune-suppressing drugs)

10. Drug Tests

    • Blood +Glucose in Urine (badsign)
    • Proteins too large for fenstrations +drugs tested

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