Kidney's Part 2 Flashcards
The ability of kidneys to remove molecules from the blood plasma by excreting them in the urine
Renal clearance
How does reabsorption affect renal clearance? How does filtration affect it? And secretion?
decreases, increases, increases
What kind of molecules are elimiated in the urine more rapidly than by just glomerular filtration?
xenobiotics
Substances that are used to evaluate GFR and why?
inulin, creatinine, they are neither reabsorbed nor secreted by tubules
Drug used to treat gout
probenecid
Why is glucose not present in urine
secondary active transport in the proximal tubule, cotransport of glucose and Na+
What happens when glucose carriers are saturated?
glycosuria
What is the renal plasma threshold for glucose?
190 mg per 100 ml blood
Fasting hyperglycemia is caused by
inadequate secretion or action of insulin
How is diabetes mellitus similar to drinking seawater
osmotic diuresis
What stimulates the parathyroid hormone secretion?
fall in plasma ca2+
What secretes the hormone that regulates renal reabsorption of na+ and k+?
adrenal cortex
Where is the primary site of aldosterone action and what does it influence?
cortical collecting duct, Na+/K+ pumps
What K+ is secreted into the late distal tbule/collecting duct and why?
K+ in the diet, so blook K+ stays the same
A k+ rich meal stimulates _____ to secrete _____
adrenal cortex, aldosterone
Reabsorption of Na+ promotes what action of K+
secretion into the filtrate
What is the primary cilium and how does it influence K+?
a mechanosensor that acts as a second messenger of sorts and can activate K+ channels –> K+ secretion
How do diuretics influence sodium and potassium
inhibits transport of na+ in nephron loop and increases delivery of Na+ to distal tubule–> more reabsorption–>more secretion of potassium
What would someone taking diuretics also want to take?
potassium supplements
What can cause hyperkalemia?
hyponatremia and adrenal insuffiency (addison’s)
What causes hypokalemia?
excessive aldosterone (hyperaldosteronism or Conn’s synrome), cushing’s syndrome, diuretics
What can hypokalemia lead to
heart arrythmia, muscle weakness
How does decrease in Na+ promote aldosterone secretion
indirectly bc leads to low blood volume which activates the renin angiotensin aldosterone system
Where is the juxtaglomerular apparatus?
where the afferent arteriole comes in contact with the last portion of the thick ascending limb
What secretes the enzyme renin and where are these cells?
granular cells, afferent arteriole
What does renin catalyze the conversion of
angiotensinogen to angiotensin 1
What converts angiotensin 1 to 2
angiotensin converting enzyme
What effects does angiotensin 2 have?
vasoconstriction, stimulates aldosterone secretion, sodium reabsorption, rise in blood volume/pressure
What kind of receptor are granular cells?
baroreceptors
Increased secretion of H+ into filtrate _____ secretion of K+
reduces
Alkalosis leads to what (in reference to K+)
hypokalemia
Primary hyperaldosteronism can lead to
hypokalemia and metabolic alkalosis
Addisons disease leads to
hyperkalemia and metabolic acidosis
Kidneys usually ______ H+ and _____ bicarbonate
excrete, reabsorb
What relationship do Na+ and H+ have in the proximal tubule
antiport cotransport, H+ replaces Na+ in the filtrate
More bicarbonate in the urine makes the urine
more alkalotic
T/F: the proximal tubule reabsorbs 80-90% of bicarbonate
true
What helps compensate for alkalosis?
More excretion of HCO3
Why is urine acidic?
distal tubules secrete H+ into filtrate using primary active transport H+ pumps
What buffers H+ in the urine?
ammonia and phosphate
What is responsible for H+ buffers?
amino acid glutamine
Example of loop diuretic
furosemide
What inhibits salt transport by the first segment of distal convulted dtbule
thiazide diuretIcs (hydrochlorothizide
What is a weak diuretic and what is it better used to treat?
carbonic anhydrase inhibitors, promotes excretion of bicarbonate (acetazolamide-diamox), acute mountain sickness
How does diamox help acute mountain sickness
decreases reabsorption of bicarbonate, mild diuretic and metabolic acidosis, which stimulates the central chemoreceptor to promote hyperventilation that aids acclimatization
What drug can act as an osmotic diuretic?
mannitol
What class of diuretic can counteract the usual negative affect of diuretics
potassium sparing diuretic
What are common ways to ruin kidney function
chronic UTI’s and hypertension
What is the first manifestation of renal damage from diabetes or hypertension and what tests for it?
microalbuminuria, urinary albumin excretion rate
What can test for acute renal failure?
creatinine clearance test
Glomerulonephritis affects what part of the kidneys and is considered what kind of disease?
basement membrane of glomerular capillaries, autoimmune
renal insufficiency directly causes
hypertension and uremia
What is uremia accompanied by and what can it lead to?
acidosis (elevated H+) and elevated K+, uremic coma
How to treat uremia?
hemodialysis
What is a more convenient way to do dialysis?
continuous ambulatory peritoneal dialysis
