control of blood water potential

Question 1

what is osmoregulation

Answer 1

the control of water potential of the blood

Question 2

structure and role of nephron

Answer 2

kidneys have around 1.5 million nephrons which excrete urea into urine and reabsorb important molecules like glucose and amino acids
-blood enters through afferent arteriole which is connected to the renal artery
-the blood is carried at high hydrostatic pressure and afferent is larger than efferent to carry large proportions of unfiltered blood in at high pressure.
-this divides into glomerulus which is a network of capillaries surrounded by the bowmans capsule.
-the high hydrostatic pressure forces small molecules like amino acids and glucose OUT of the blood.
-bowmans capsule contains specialised podocytes which are close to capillaries
- capillaries have gaps between epithelial cells for small molecules to move out of
-podocytes have pedicytes which allow movement of small molecules
- the basemnet membrane is a layer of collogen between podocytes and epithelial cells which small mols pass through

Question 3

ultrafiltration- formation of filtrate in the glomerulus

Answer 3

blood moves in through afferent arteriole
this is larger than effernt arteriole
high hydrostatic pressure
forces urea and glucse etc out
filtrate moves pout through pores in endothelium of capillary
into basement membrane

Question 4

osmoregulation

Answer 4

if the a person is dehydrated the osmoreceptors in the hypothalamus detect this change and water within these receptors leaves via osmosis
pituitary gland releases ADH
ADH travels in the blood to the kidneys attaching to ADH receptors activating the intracellular enzyme phosphorylase
this causes vesicles containing aquaporins to fuse iwth the plasma membtrane increasing permeability of collecting duct reducinng absoprtion of water