Physiology
Physiological insulin resistance in adolescence
Bile salts assist fat absorption by producing micelles
Bilirubin is excreted in urine and bile
Fluids:
ECV controlled by Na balance
EC tonicity controlled by water balance
IntravascV and tonicity (plasma) controlled by neur, endo, para, behaviour
Vasopressin (T1/2 5 mins) made in Hypothalamus and transported to Post Pit along axons
↑ plasma tonicity > osmoreceptor > posterior pit secretion of vasopressin (peptide hormone) > insertion of aquaporin > renal resorption H2O
283 mOsm/kg = vasopressin
293 mOsm/kg = thirst
Activation of retention before thirst allows retention of imbibed H2O
Cl- > Macula densa > Renin > Angio (blood vessels) > ATII (ACE in lungs) > Aldosterone (Adr Cort) > Vasoconstriction + Hypothalamus > Thirst
↑BP > carotid (CNIX)/Aortic (CNX) arterial baroreceptor > reduce HR/PVR
↓BP > Venous baroreceptors > thirst and kidneys
Natriuretic peptide
Chemoreceptors in the oropharynx down regulate vasopressin post intake of H2O
Urea cycle:
Ammonium is converted to Urea in urea cycle by liver
Failure = high ammonia causing hepatic encephalopathy
Bile salts assist fat absorption by producing micelles
Bilirubin is excreted in urine and bile
Fluids:
ECV controlled by Na balance
EC tonicity controlled by water balance
IntravascV and tonicity (plasma) controlled by neur, endo, para, behaviour
Vasopressin (T1/2 5 mins) made in Hypothalamus and transported to Post Pit along axons
↑ plasma tonicity > osmoreceptor > posterior pit secretion of vasopressin (peptide hormone) > insertion of aquaporin > renal resorption H2O
283 mOsm/kg = vasopressin
293 mOsm/kg = thirst
Activation of retention before thirst allows retention of imbibed H2O
Cl- > Macula densa > Renin > Angio (blood vessels) > ATII (ACE in lungs) > Aldosterone (Adr Cort) > Vasoconstriction + Hypothalamus > Thirst
↑BP > carotid (CNIX)/Aortic (CNX) arterial baroreceptor > reduce HR/PVR
↓BP > Venous baroreceptors > thirst and kidneys
Natriuretic peptide
Chemoreceptors in the oropharynx down regulate vasopressin post intake of H2O
Urea cycle:
Ammonium is converted to Urea in urea cycle by liver
Failure = high ammonia causing hepatic encephalopathy