Regulation Of Water Content 🚽

Question 1

What is absent in glomerular filtrate

Answer 1

Plasma protein and blood cells because they are too large to pass through

Question 2

What will be reabsorb and how they be reabsorbed

Answer 2

All glucose and amino acids and most salts reabsorbed by diffusion and active transport
About 85% of water reabsorbed by osmosis
50% of urea absorbed by diffusion

Question 3

Adaptive features of proximal convoluted tubule for reabsorption

Answer 3

1. High coiled and long —> increase surface area and time for reabsorption
2. Epithelial cells are one cell thick —> shorter the diffusion distance
3. Microvilli on epithelial cells —> increase surface area for reabsorption
4. Epithelial cells contain mitochondria —> provide enough energy for active transport
5. Surrounded by dense capillary network —> maintain steep concentration gradient and increase diffusion rate and hence reabsorption

Question 4

Process of osmoregulation when water potential of blood is lower than normal

Answer 4

1. The low water potential of blood is detected by the osmoreceptors in hypothalamus
2. The pituitary gland is stimulated to release more ADH
3. The second coiled tubule and collecting duct become more permeable to water
4. Large proportion of water is reabsorbed
5. Water potential in blood rises and small volume of urine is produced