Formation of Urine: A Properly Working Kidney

Movie  1:50

filtration

Secretion

Reab

sorptio

n  (bac

k  into  blood

)

Cellular  Processes(ATP)

(fine  tuning)

Filtration Amino  acids UreaCreatine  PhosphateGlucose Ions

Water

Reabsorption

Amino  acidsOther  nutrients

Amino  acids

UreaCreatine  Phosphate

Glucose

IonsWater

Secretion

Amino  acids

Urea

Creatine  Phosphate

Glucose

Ions

Water

Formation of Urine involves three main processes:

1. Filtration - glomerulus and Bowman's capsule - all small molecules - nondiscriminate meaning good and bad leave blood plasma

2. Reabsorption - tubular system - PCT reabsorbs all valuable molecules; Loop of Henle reabsorbs water; DCT reabsorbs ions that the body requires because only bad molecules or excess molecules remain in tubular system, urine is forming and becoming more concentrated.

3. Secretion - DCT - if there are still waste products or excess products in the blood that need to be removed, these molecules can be secreted from the blood INTO the DCT for excretion.

Conc

entration  of  Urin

e  mol/L

OTHER  CELLULAR  WASTES