P: Body water

Question 1

What are the functions of the plasma membrane

Answer 1

• Transport molecules in and out of cell
• Cell recognition via cell surface antigens
• Cell communication
• Cell adhesion molecules
• Enzymatic activity
• Determination of cell shape

Question 2

What are the 3 types of plasma membrane proteins?

Answer 2

Integral, lipid-anchored & peripheral.

Question 3

What are the 4 types of membrane transport proteins?

Answer 3

Aquaporins (water channels)
Ion channels
Solute carries (uniporter, symporter, antiporter)
ATP dependent porter

Question 4

Difference between basolateral and apical membranes?

Answer 4

Apical faces external environment and is involved in absorption + secretion, basolateral membrane mediates attachment to underlying tissue.

Question 5

ADH present?

Answer 5

AQP-2 inserted into apical membrane of collecting duct cells - water is reabsorbed - urine concentrated + water retained

Question 6

No ADH present?

Answer 6

AQP-2 says in cytoplasm of epithelial cell - water is not reabsorbed - urine is dilute - lots of water lost.

Question 7

Where is ADH produced?

Answer 7

Produced in hypothalamus and secreted by posterior pituitary. Stimulated by hypothalamic osmoreceptors.

Question 8

Rank plasma, intracellular and interstitial fluid in order of decreasing volume?

Answer 8

Intracellular, interstitial, plasma