Physiology

Question 1

What change occurs to arterial pCO2 in pregnancy?

Answer 1

Reduced

Question 2

What reduces arterial pCO2 geographically?

Answer 2

Altitude > 2500m

Question 3

Does reduced arterial pCO2 increase cerebral blood flow?

Answer 3

No

Question 4

What is the effect of reduced arterial pCO2 on urine?

Answer 4

Makes it more alkaline

Question 5

How does pH affect calcium?

Answer 5

Acidosis favors release of ionized Ca
Alkalosis favors binding of Ca and Dec ionized Ca
Total Ca level unchanged

Question 6

Where is somatostatin produced?

Answer 6

Delta cells of pancreas and hypothalamus (growth hormone inhibiting hormone)

Question 7

What do pancreatic beta cells produce?

Answer 7

Insulin and amylin

Question 8

What are the contractant molecules of the myometrium?

Answer 8

Oxytocin (produced by uterus)
Prostaglandins (F2alpha)

Question 9

How do the contractant molecules of the myometrium stimulate contractility?

Answer 9

Oxytocin and prostaglandins act via G protein coupled receptors to activate phospholipase C which increases intracellular Ca2+ concentration and activation of myosin light chain kinase, and Ca2+/calmodulin dependent protein kinase

Positive feedback loop - oxytocin stimulates uterine prostaglandin synthesis and prostaglandins up regulate oxytocin receptor expression

Question 10

What are the relaxant molecules of the myometrium?

Answer 10

NO, relaxin, progesterone, (prostacyclin)

Question 11

What is the action of myometrium relaxants?

Answer 11

Via cAMP and cGMP, activate dependent protein kinases which dephosphorylate myosin light chain and limit contraction force

Progesterone also inhibits synthesis and action of oxytocin and prostaglandins and inhibits gap junctions