Flashcards in physiology final Deck (362)
What is the job of the kidneys?
maintain the constancy of the body's internal environment
How do they accomplish this?
By regulating the volume and composition of extracellular fluids
What do they use to excrete metabolic end products?
What else are the kidneys involved with?
regulation of the total amount of many important substances in the extracellular matrix.
What are the 7 main functions of the kidneys?
1- regulation of the concentration of numerous ions. 2- excretion of organic compounds. 3- fluid balance. 4- acid-base balance. 5- blood pressure regulation. 6- erythrocyte volume regulation. 7- Vitamin D activation
How do the kidneys accomplish #1? (from previous ?)
excretion or preservation of Na, Cl, K, Ca, PO4 - balance their intake, production or excretion through other routes
How is #2 accomplished?
1) elimination of substances like urea and creatinine in amounts equaling their production rates. 2)elimination of drugs, FO, and toxins
1)regulate water. 2) regulate osmotic pressure of EC fluids. 3) produce urine
excretion of H+ or HCO2 as needed
renin-angiotensin system and renal-body fluid balance system
through formation and release of erythropoetin
vitamin D hydroxylation to render it useful.
How much more salt than water do humans typically consume each day?
How is that excess salt/water disposed of?
What sensors determine how much is to be excreted?
water volume sensors, salt sensors, osmolality sensors,
How do these sensors instruct the kidneys on what to do?
Where does all the action in the kidney take place?
What is a nephron encased in?
a maze of peritubular capillaries
What are the components of a nephron?
1) Glomerular capsule, 2) PCT, 3) loop of Henle, 4) DCT, 5) collecting duct
What are the components of the vasculature of a nephron?
1) intralobular artery. 2) afferent arteriole 3) glomerulus 4) efferent arteriole 5) peritubular capillaries 6) venule and intralobular vein
What are the 3 versions of a nephron?
1) superficial. 2) mid-cortical. 3) juxtamedullary
What 3 activities do kidneys engage in?
1) filtration 2) reabsorption 3) secretion
Where is the bulk of the work done?
in glomeruli and PCTs
What remains in the final end of the tubules?
How does blood enter the kidney and nephron?
through Renal artery
What does the blood return to circulation through?
The nephron is said to "clear" what?
the blood of unwanted substances - removes unwanted agents from the plasma
What is clearance?
the amount of plasma cleared of a given substance
How can glomerular filtration rate be measured?
by looking at the clearance of something that is freely filtered and not reabsorbed at all.