Physiology- Regulation of osmolality

Question 1

what are the 2 factors that affect ADH secretion?

Answer 1

• ECF volume
• Increase in plasma osmolarity that affects tonicity of cell

Question 2

what is the Juxtaglomerular apparatus composed of?

Answer 2

• juxtaglomerular cells
  
  • = media of afferent arteriole (just before enters glomerulus) contains epithelial cells with granules
• macula densa
  
  • specialised loop of cells in distal tubule

Question 3

what does JG apparatus secrete?

Answer 3

renin

Question 4

role of renin?

Answer 4

cleaves angiotensinogen in blood into angiotensin I

Question 5

factors that stimulate renin release?

Answer 5

• Low BP in afferent arteriole at level of JG apparatus
• Reduced NaCl at macula densa
• Increase sympathetic activity

Question 6

factors that inhibit renin release?

Answer 6

• feedback of Angiotensin II
• ADH

Question 7

Outline all physiological changes in a scenario of increased salt and water loss

Answer 7

Question 8

what is caused by the effects of aldosterone?

Answer 8

ANP= atrial natriuretic peptide release which promotes Na+ excretion

Aldosterone –> increased weight because of retention of H2O with ­Na+ –> volume expansion

stimulation of release of ANP from atrial cell

loss of Na+ and H2O ie natriuresis