urinary system three Flashcards
What is the main function of the nephrons and collecting ducts?
Control the volume and composition of body fluids and produce urine
What three processes produce urine as the final product?
Glomerular filtration, tubular reabsorption, and tubular secretion
What is tubular reabsorption?
the process of moving water and solutes out of the filtrate and back into the bloodstream
Where is most reabsorption occuring?
Proximal convoluted tubule
Why is tubular secretion important
helps control blood ph because of secretion of H+ and helps eliminate certain substances
What is the renal plasma threshold?
The plasma concentration at which a specific substance or ion appears in the urine
five functions of the PCT
reabsorption of organic nutrients, active reabsorption of ions, reabsorption of water, passive reabsorption of ions, secretion of H+
Countercurrent exchange
exchange between tubular fluids moving in opposite directions between two parallel nephron loops
benefits of countercurrent multiplication
efficiently reabsorbs solutes and water and establishes concentration gradient
What hormone stimulates the reabsorption of Na in exchange for secretion of K?
Aldosterone
What happens if calcium levels are too low?
parathyroid released PTH whcih increases calcium release from bones, uptake in intestines, and reabsorption from urine
What happens if calcium level is too high?
increase calcium in bones, decrease calcium in intestines and decrease reabsorption from urine. Calcintonin released
How do the PCT and DCT respond to acidosis
they deaminate amino acids and tie up hydrogen ions to yield ammonium ions and bicarbonate ions.
