renal control of acid-base status and renal endocrinology Flashcards
how does the kidney retain water
through antidiuretic hormone AKA vasopressin
ADH: created in? acts on? effect?
- created in the posterior pituitary
- acts on the collecting ducts and distal renal tubule
- effect: resorption of water
how does the kidney regulate calcium and phosphorous?
parathyroid hormone
parathyroid hormone: created in? acts on? effect?
- created in the parathyroid gland
- acts on the kidney (distal tubules), bones, intestines
- effect is net absorption of calcium and excretion of phosphorus
what is parathyroid hormone related peptide (PTHrp)
occasionally expressed in a variety of types of neoplasia - acts just like PTH!
how does the kidney retain sodium
through aldosterone
aldosterone: created in? acts on? effect?
- created in the zona glomerulosa cells of the adrenal cortex
- acts on the cortical collecting tubule/distal tubules
- effect is sodium reabsorption and potassium excretion in distal tubules (also important acid-base regulation)
what are the stimuli for aldosterone
- increased blood potassium concentration
- angiotensin II
what does aldosterone stimulate
- the sodium potassium ATPase pump on the basolateral membrane of the cortical collecting tubules
- also the hydrogen ion excretion from the collecting tubules
how does the kidney retain sodium
angiotensin II
angiotensin II: created in? acts on? effect?
- created in the liver (angiotensinogen -> AT I (renin) -> ATII (ACE in the lungs) -> kidney
- acts on the proximal tubules, loops of henle, and distal tubules and collecting tubules, efferent arterioles
- effect: robust conservation of sodium and water from the renal tubules
what is the body’s most powerful sodium retaining hormone
angiotensin II
angiotensin II is increased when:
there is excessive loss of extracellular fluid volume or low blood pressure events
angiotensin II stimulates ____ secretion which in turn increases sodium resorption
aldosterone
angiotensin II constricts the efferent arterioles and this reduces:
peritubular capillary hydrostatic pressure which increases net tubular reabsorption from proximal tubules
what does the macula densa sense
decreases in NaCl
what does the juxtaglomerular cells sense
decrease in blood pressure
how does the heart affect the kidney’s regulation of blood pressure
atrial natriuretic peptide (ANP)
ANP: created in? acts on? effect?
- created in the atrial myocardium
- acts on the kidney
- effect is increase sodium excretion
ANP is stimulated by:
high blood volume in the atria
release of ANP causes:
- direct decrease in sodium reabsorption in the distal tubules
- inhibition of renin production by the juxtaglomerular cells, leading to all the downstream affects of decreased angiotensin II
which of the following hormones has effects that increase sodium resorption in the blood?
- aldosterone
- angiotensin II
- vasopressin
- ANP
- PTH
aldosterone and angiotensin II
what is the general systemic effect of increasing your blood sodium
increase in blood pressure
regulation of H+ in the blood by:
- secretion of H+
- reabsorption, creation, secretion of HCO3-
what is the net effect of cellular mechanisms of acid-base control
for every H+ that is secreted into the lumen, 1 HCO3- is absorbed
what are the two big urinary buffers
- ammonia buffer
- phosphate buffer
what is the outcome of ammonia buffer
H+ bound to NH3 constitutes a net GAIN of HCO3-
what occurs in alkalosis
- tubular secretion of H+ is reduced to a level that is too low to achieve complete HCO3- resorption
- enabling the kidneys to excrete HCO3- into the urine
- no excess H+ is available to combine to with the nonbicarbonate buffers, so no additional bicarb is made and resorbed wither
what occurs in acidosis
- tubular secretion is sufficient to resorb the filtered HCO3-, with extra left over to bind with the nonbicarbonate budders - ammonia excretion
stimulus for increased H+ secretions are:
- increased PCO2 (respiratory acidosis)
- increased H+ in the blood
- aldosterone
paradoxial aciduria
low potassium
- decreased K intake
- metabolic alkalosis - causes the shift of potassium out of the blood and into the cells (left displaced abomasum)
- effect of aldosterone - potassium wasting (hypovolemia)
(aciduria in the face of alkalosis)
