The kidney functions to filter waste from the blood and regulate homeostasis. It contains nephrons, the functional units, located in the renal cortex. Nephrons filter the blood via the glomerulus, reabsorb most water and nutrients, and secrete some substances, forming urine. Urine drains from the renal pyramids and calyces into the ureters and out of the body. The kidney filters around 45 gallons of blood per day.

4. Arterial
blood
supply to
the left
kidney!

5. a. Excrete (get rid of) metabolic wastes in
the blood by filtering them out and
excreting them in urine.
b. Maintain homeostasis of…
a. Amount of H20
b. Amount of salts
c. Amount of Na+/K+
d. pH of body fluids

8. Renal cortex: contains nephrons 
functional unit of kidney (1 million per
kidney!)
Medulla: composed of renal pyramids
Renal pyramids: contain collecting ducts
Calyx: drain urine from each renal
pyramid and into ureter

14. a. Filtration: Filtration occurs in
the glomerulus. Blood pressure
forces water, salt, glucose,
amino acids, and urea into the
glomerular capsule. Proteins
and blood cells are too big to
cross the membrane; they
remain in the blood. The fluid
that enters the renal tubules is
called the filtrate.

17. a. 15 gallons
b. 25 gallons
c. 45 gallons
d. 125 gallons

18. 125 milliliters of blood per minute
45 gallons of blood in 24 hours!!!

19. b. Reabsorption: As the
filtrate flows through the
renal tubule, most of the
water and nutrients are
reabsorbed into the blood.
The concentrated fluid that
enters the collecting duct
is called urine.

20. c. Secretion: Some
substances that were
reabsorbed are secreted
into the filtrate, such as
certain drugs, excess
potassium, or as a final
way to control blood pH.

26. Know the pathway of urine from the
kidneys to exterior of the body!
What is the functional unit of the nephron?
When is the end product of kidney
function?