Osmoregulation

• process of PCT and loop of henle?

  osmosis
• process of DCT and collecting duct?

  active transport
• roles of ADH in osmoregulation?

  Increase water reabsorbed by increasing collecting ducts permeability

  • concentrates urine
  • increases water reabsorbed from urine

  Increases blood volume and pressure

  Decreases plasma osmolarity
• Where is aldosterone released from?

  adrenal cortex.

  released when low blood volume
• where does ADH affect?

  collecting duct, DCT
• where does aldosterone effect?

  DCT

  collecting duct
• what does aldosterone do?


  increase reabsorption of Na & Cl

  Decrease active K reabsorption

  Increase osmosis (water reabsorption)

  • as Na re-enter blood, stimulates movement of water back too

  Increases water reabsorption

  Increase blood vol

  Increase plasma osmolarity
• does aldosterone increase or decrease plasma osmolarity

  increase
• does ADH increase or decrease plasma osmolarity

  decrease
• Thirst Reflex

  S: Increase osmotic pressure due to decreased blood volume. Mouth feel dry

  R: Osmoreceptors (hypo) detect decreased blood vol and give person conscious recognition that they feel thirsty

  M: hypothalamus

  E: dry throat

  R: drink fluid; water absorbed into blood via alimentary canal
• Water Intoxication?

  cell increase water uptake (osmosis) when electrolyte concentration low

  • eg) intense excercise, electrolytes not replenished and large amount water consumed
  • Light head, headache, vomit, death
• dehydratiON?

  Excessive water loss

  Lose more water than take in (lost 2% normal fluids)