Physiology Flashcards
Average liquid intake/output per day
2500 ml
hypotonic
cells swells
hypertonic
cell shrinks
what is the only organ in the body that has two capillary networks?
kidney
basic mechanisms of urine formation
filtration, reabsorption, secretion, excretion
renal clearance of a substance
the volume of plasma completely cleared of a substance per min by the kidneys.
How is clearance used to measure GFR?
For a substance that is freely filtered, but not reabsorbed or secreted (inulin, 125 I-iothalamate, creatinine), renal clearance is equal to GFR
Theoretically, if a substance is completely cleared from the plasma, what does its clearance rate equal?
renal plasma flow
Which of the following molecules pass freely through the filtration membrane into the capsular space: H2O, electrolytes, glucose, amino acids, lipids, vitamins, nitrogenous wastes?
All of them pass freely
What happens when the basement membrane is damaged?
plasma proteins or blood cells pass through
Normal GFR for average adult male
125 ml/min
Describe the myogenic mechanism of the nephron that prevents drastic changes in GFR when BP rises
Constriction of the afferent arteriole and Dilation of the efferent arteriole
What effect do prostaglandins, fever, glucocorticoids, and hyperglycemia have on GFR?
increase it
What percent of the cardiac output do the kidneys receive?
22%
How much of the glomerular filtrate does the PCT reabsorb and return to the blood?
65%
How does the PCT reclaim large solutes/proteins?
endocytosis
What happens to a solute if all its transporters are occupied?
some solute will remain in the tubular fluid and appear in the urine. ex- glucose (DM)
How permeable is the thin descending loop of Henle to H2O?
very permeable
What is transported in the thick ascending loop of Henle?
NaCl and K+
What part of the renal tubules is under hormonal control?
distal convuluted tubule
Where does aldosterone act to increase Na+ absorption and K+ secretion?
in the DCT and cortical portion of the collecting duct
Effects of ANP
inhibits sodium and water reabsorption, increases the output of both in the urine
What is the purpose of tubular secretion?
waste removal and acid-base balance.
What is the driving force for water reabsorption?
The high osmolarity of extracellular fluid generated by NaCl and urea
