Mechanisms of urine formation

Question 1

How many times does the kidneys filter the bodys entire plasma a day?

Answer 1

60 times a day

Question 2

the filtrate contains and loses:

Answer 2

contains: all plasma components except protein
loses: water, nutrients, and essential ions to become urine

Question 3

urine formation involves three major processes:

Answer 3

1. glomerular formation
2. tubular reabsorption
3. secretion

Question 4

1st step in urine production: Glomerular Filtration

Answer 4

1. more efficient because: filtration membrane is more permeable, glomerular blood pressure is higher, has higher net filtration pressure
2. plasma proteins aren’t filtered and are used to maintain oncotic pressure of the blood

Question 5

Glomerular filtration rate(GFR)

Answer 5

1. total amount of filtrate formed per minute by da kidneys
2. factors:
   a. total surface area
   b. filtration membrane permeability
   c. net filtration pressure
3. GFR directly proportional to NFP

Question 6

Regulation of Glomerular filtration

Answer 6

If too high: needed substances cannot be reabsorbed quick enough and are lost in urine
if too low: everything is reabsorbed including wastes which are normally disposed of
THREE MECHANISMS CONTROL GFR: renal autoreg.(intrinsic), neural controls, hormonal mechanism