A TEST- Urinary system - Urine Formation
Three Processes of Urine Formation
1) Glomerular Filtration
2) Tubular Reabsorption
3) Tubular Secretion
Where does Glomerular Filtration happen
in the Renal Corpuscle
Where does Tubular Reabsorption happen
Peritubular Capillaries
Where does Tubular Secretion happen?
Peritubular Capillaries
Glomerular Filtration
GF
GF: What does Glomerular filtration do?
Filters plasma at the glomerular Capillaries (most will be returned)
GF: What do Fenestrea (tiny openings) do?
make tubules more permeable
GF: Podocytes
special cells that keep plasma proteins in
GF: how much fluid does GF produce?
180 liters per fluid
Tubular Reabsorption
TR
TR: where does Tubular Reabsorption take place?
mostly in PCT but it also occurs through the rest of the renal tubule
TR: What does Tubular Reabsorption do?
returns water, electrolytes, glucose, AAs & NaCI to the blood
TR: what processes are used for returning the molecules back to the bloodstream?
Osmosis, diffusion, and active transport
PCT Transport Mechanisms
PCT TM
PCT TM: What processes transport what molecules?
Active transport- Glucose, Amino Acids, and Sodium (Na+)
Passive transport- CI-
Osmosis- H2O
PCT TM: What percent of NA+ Ions are reabsorbed by active transport?
70%
PCT TM: What and how do the negatively charged ions follow?
They follow the positively charged ions (NA+) using passive transport because positive will attract to negative passively
PCT TM: What follows the NA+ and negative ions?
Water follows by osmosis
PCT TM: What happens when the Tubular volume decreases greatly?
By the end of the renal tubule, almost all the NA+ and H20 are reabsorbed
Tubular Secretion
TS
TS: How much plasma is left to filter?
80% (20% done by glomerulus)
TS: Where does Tubular secretion take place?
The DCT
TS: What happens during tubular secretion?
Active transport of substances the body must get rid of
- H+
- Urea
- K+
- medications
Chemical composition of urine
CCU
CCU: How much percent of urine is water?
95%
CCU: How much percent of Nitrogenous wastes (urea, uric acid), electrolytes (NA+, K+) & traces of Amino Acids makeup urine?
5%
CCU: What do abnormally high amounts of anything mean?
pathology and disease