Physiology final- renal Flashcards
Functions of the kidney
regulate extracellular fluid volume and BP, regulation of osmolarity, maintenance of iron balance, regulation of pH, excretion of wastes and production of hormones
how kidneys balance water
kidneys can’t make water so they conserve it by concentrating urine.
vasopressin (AVP or ADH)
hormone to retain water, when levels are high, urine is more concentrated. made in hypothalamus and secreted from the posterior pituitary. increases osmolarity and decreases blood pressure
Diuresis
removal of excess water in urine
Diuretics
drugs that promote urine excretion. important in hypertension and congestive heart failure.
Things that trigger Vasopressin
Low blood pressure, low blood volume, higher than about 300 mOsM
Increasing ECF Osmolarity
increased thirst, increased vasopressin secretion
Decrease in ECF volume
increased vasopressin, increased thirst,
alcohol
acts as a vasopressin, unintended diuretic
sodium reabsorption occurs mostly in the
proximal tubule
Aldosterone
hormone made in the adrenal cortex. primarily for renal sodium reabsorption. triggered by high K+ levels and low blood pressure.
RAAS
Granular cells produce the enzyme renin. low BP increases renin production which converts angiotensinogen from the liver into ANG-I which is converted into ANG-II which tells the adrenal cortex to release aldosterone which increases sodium reabsorption.
increase in sodium reabsorption leads to
higher blood pressure, ECF volume expansion and increased blood volume
Natriuretic peptide (ANP)
produced by myocardial cells in response to stretching from increased blood volume to tell kidney to decrease sodium reabsorption. tells the hypothalamus to decrease vasopressin and adrenal cortex to decrease aldosterone. Increases diuretic action, decreases volume and pressure.
properties of dehydration
low bp, low volume, high osmolarity.
