Osmoregulation

Question 1

What is a hyper, hypo and isotonic solution?

Answer 1

Hypertonic: Solution of higher concentrate

Hypotonic: Solution of lower concentrate

Isotonic: Solutions of the same concentrate on either side of the membrane

Question 2

How is osmolarity of the extracellular fluid regulated?

Answer 2

The body increases or decreases the amount of water present so that the ICF AND ECF are isotonic

Question 3

What is the stimulus response model for a change of water volume?

Answer 3

Stimulus: Change is water volume, causing change in osmolality, blood volume and blood pressure

Receptor: Baroreceptors, osmoreceptors

Modulator: Cells in the kidney, hypothalamus and pituitary gland

Effector: Cells in the distal convoluted tubule and collecting duct, the hypothalamus

Response: Alteration in reabsorption of water which changes the osmolality, pressure and volume of blood.

Question 4

What role does ADH have in osmoregulation?

Answer 4

ADH is released after an increase in osmolality is detected, it works to decrease the change.

Question 5

What is ADH pathway 1?

Answer 5

ADH increases water reabsorption in the nephrons of the kidney, by increasing the no. of Aquaporins inserted into the cells of the distal convoluted tubule and collecting duct

Question 6

What is ADH pathway 2?

Answer 6

ADH signals to the thirst centre in the hypothalamus, generates a feeling of thirst
(Leads person to drink, increases water volume in the body)

Question 7

How is blood pressure and volume increased?

Answer 7

Renin is released from the kidneys, through a series of reactions, renin causes the release of aldosterone.

Aldosterone activate Na/K pump, Na is absorbed more and K is excreted in urine. Due to osmosis water follows sodium