renal part 3 Flashcards
what is the normal pH range for the human body? what is the normal bicarbonate concentration?
normal pH range = 7.35-7.45
[HCO3-] = 24 m
_______ acids can be exhaled or dissipated by the lungs; re: CO2
volatile
________ acids from metabolism or the diet, and they must be regulated by the renal system
non-volatile
________ bind to excess or free H+ to increase acid carried in urine without decreasing pH
buffers
what buffers are used by the kidney?
HCO3- (bicarbonate)
HPO42- (phosphate)
NH3 (ammonium)
_______ production within tubular cells eliminates H+ and produces an HCO3- that is reabsorbed
ammonium
The kidney regulates acidity of the urine by regulating _______ reabsorption
HCO3- (bicarbonate)
what are the 3 ways the kidney can regulate blood pH by using bicarbonate ions?
- decrease body pH by not reabsorbing all HCO3-
- no effect on body pH by reabsorbing all HCO3-
- increase body pH by reabsorbing all and producing more HCO3- (typical)
production and reabsorption of what molecule results in H+ secretion
bicarbonate
where does bicarbonate reabsorption begin?
proximal tubule
how is H+ secreted by the proximal tubule cells?
H+ is secreted via Na+ / H+ antiporter
can also have H+ ATPase pumps and H+/K+ ATPase pumps operating to secrete H+
in the proximal tubule, HCO3- is transported/reabsorbed across _________ membrane
basolateral
80% of filtered _________ is reabsorbed in proximal tubule
HCO3- (bicarbonate)
how is H+ secreted by the cells of the late distal tubule, and the collecting duct?
H+ is secreted via an H+ ATPase pumps and an H+/K+ ATPase pump
_________ cells of the distal tubule, and collecting duct, will excrete H+
intercalated
what causes alkaline urine?
incomplete reabsorption of HCO3-
increase excretion of HCO3- by not neutralizing all that is in the tubular fluid
Cells of the proximal tubule detect intracellular pH and can alter _________ activity accordingly
Carbonic anhydrase (CA)
if the body is acidic, the kidney can use ______ as an additional buffer to increase excretion of H+
phosphate (HPO4- )
After all HCO3- has been reabsorbed and HPO4- is depleted, the kidney will produce what?
ammonium (as a third buffer)
NH4+ is produced in the proximal tubules by metabolism of _________
glutamine
the NH4+ system is regulated by what?
systemic pH
acidosis upregulates synthesis of enzymes for ________ metabolism
glutamine
Much of the NH4+ leaving the proximal tubule is reabsorbed by what structure?
the ascending limb of the loop of Henle
diffusion trapping can increase the concentration of ______ in the urine
NH4+ (ammonia)
Net acid excretion (NEA) occurs after all filtered _________ is reabsorbed
HCO3-
what causes Respiratory acidosis? how does the kidney respond to this?
low pH due to CO2 build-up
renal compensatory response: produce new HCO3-
what causes Respiratory alkalosis? how does the kidney respond to this?
high pH due to low PCO2
renal compensatory response: excrete HCO3-
what causes respiratory alkalosis?
hyperventilation, anxiety, altitude, fever, drugs
what causes Metabolic acidosis?
causes include diabetic ketosis, diarrhea, renal failure
how does the respiratory system respond to metabolic acidosis? the kidneys?
respiratory compensatory response: hyperventilate
renal compensatory response: produce new HCO3-
what causes metabolic alkalosis?
causes include vomiting, antacids, hemorrhage
how does the respiratory system respond to metabolic alkalosis? the kidneys?
respiratory compensatory response: hypoventilate
renal compensatory response: excrete HCO3
gastrointestinal absorption of _________ is balanced by renal excretion
calcium
__________ increases excitability of neural and muscle tissue; tetany
hypocalcemia
what are the effects of hypercalcemia?
cause cardiac arrhythmia and disorientation; can lead to death
A decrease in ___________ will increase the amount of free Ca2+
plasma pH
T/F: acidosis can lead to hypocalcemia
FALSE
alkalosis can lead to hypocalcemia
what 3 hormones regulate calcium levels?
1) parathyroid hormone (PTH)
2) calcitriol
3) calcitonin
when is PTH secreted? what does it cause?
- released in response to hypocalcaemia
- increases bone resorption, increases renal Ca+ reabsorption
PTH causes the production of what other hormone?
calcitriol
how does calcitriol effect calcium uptake?
stimulates active transport mechanism for Ca2+ absorption in the intestine
what is the molecular precursor for calcitriol?
vitamin D
___________ will facilitates action of PTH and increases renal Ca2+ transport
calcitriol
_________ (a hormone) is released in response to hypercalcaemia
calcitonin
where is most calcium reabsorbed?
proximal tubule
how is calcium absorbed by the thick ascending limb?
transcellular and paracellular transport
what part of the nephron contains a basolateral calcium pump?
distal tubule
what regulates the expression of Ca2+ transporters on the distal tubule?
regulated by PTH
what structure of the nephron is NOT associated with Ca2+ reabsorption?
collecting duct
how does calcitriol effect the GI tract?
causes INCREASED absorption of calcium (and phosphate)
