33. Renal Function Flashcards
What are the functions of the kidneys?
Maintain blood volume, ion concentration, and pH Regulate BP Produce RBC (via erythropoietin)
Where does the reabsorption of water occur?
Where does the reabsorption of Na+ and Cl- occur?
Descending loop of Henle
Ascending loop of Henle
How is reabsorption aided in the loop of Henle?
Hypertonic environment created by counter current
What is the amount of plasma filtered by the kidneys?
125 mL/min
What is the clearance of a substance?
The plasma volume that would be cleared of a substance per minute
What is the function of the convoluted tubule?
Retrieve salt, ions, and nutrients
What type of capillaries are present in the kidney?
Fenestrated
What forces cause fluid motion across the capillary wall in the kidneys?
Hydrostatic pressure difference (high in capillary, low in cells) and osmotic pressure difference (larger in blood)
How is osmotic pressure generated in the kidney?
By dissolved protein
How is the rate of formation of the interstitial fluid measured?
Capillary filtration coefficient x net pressure difference (hydrostatic - osmotic)
What is the function of podocytes in the kidney?
Support (required because of high pressures in kidney)
How does the kidney regulate blood pressure?
Sympathetic discharge of the renal nerve causes arteriolar vasoconstriction and decreased secretion of NaCl to increase blood volume
How does countercurrent multiplication work in the kidney?
Concentration of NaCl increases down the descending loop, then pumped out in ascending loop
How is ADH release stimulated?
Hypertonicity (increased salt levels) or hypovolemia
How does ADH increase water retention?
Causes aquaporin insertion into the collection duct to dilute interstitial fluid
