Glomerular filtration rate and its regulation And factors affecting Gfr By Ritik Bansal

1. BY:- RITIK BANSAL
ROLL NO. - 115

2. Overview
• DEFINITION
• MECHANISM OF GLOMERULAR FILTRATION
• MEASUREMENT OF GFR
• FACTOR AFFECTING GFR
• REGULATION OF GFR

3. DEFINITION:-
• Glomerular filtration rate is defined as the amount of filtrate
formed by glomerular filtering membrane of both the kidneys
in a unit time.
MECHANISM OF GLOMERULAR FILTRATION
Glomerular filtration occur through the glomerulocapsular
filtration barrier that consist of fenestrated capillary
endothelium, the basement membrane, and podocytes of
capsular epithelium.

4. • GFR is determined by
1. The sum of Hydrostatic pressure and colloid osmotic pressure across
the glomerular membrane, which give net filteration pressure.
2. Glomerular capillary filtration coefficient (Kf).
GFR = Kf × Net filtration pressure
GFR = Kf × (Pc – PB − ∏c + ∏B )

5. Filtration Coefficient
• It is the product of glomerular capillary wall permeability and the
effective filtration surface area(size of the capillary bed).
It cannot be measured directly, but it is measured experimentally
by dividing the rate of glomerural filtration by net filtration
pressure.
Kf = GFR / Net filtration pressure
* Increase Kf raises GFR and decrease Kf reduces GFR

6. Measurement Of GFR
Inulin Clearance Test:- It is measured by measuring the
concentration of the inulin in urine and the plasma
concentration of inulin .
GFR =

7. Effect of Arteriole resistance on GFR

8. Factors Affecting GFR
1. Change in renal blood flow
2. Glomerular capillary hydrostatic pressure
3. Change in capsular hydrostatic pressure
4. Oncotic pressure
5. Glomerular capillary permeability
6. Effective filtration surface area
7. Shape, size, and electrical charge of the macromolecule.
Filtration Fraction:- It is the ratio of the GFR to renal plasma
flow.
It ranges between 0.16 to 0.20

9. REGULATION OF GFR
• Neural Mechanism
• Hormonal Mechanism
• AutoRegulatory Mechanism
Neural Mechanism:-
Both afferent and efferent arterioles are innervated by sympathetic
fibers.
Activation of sympathetic fibers cause constriction of the renal
arteriole and cause decrease in renal blood flow hence, decrease in
GFR.
The renal sympathetic nerves seems to be more important in reducing
GFR during severe, acute disturbances for a few minutes to a few
hours, such as brain ischemia, or severe hemorrhage.

10. Autoregulatory Mechanism
The autoregulation of GFR maintain a constant
rate of glomerular filtration despite change in
systemic arterial pressure within the range of
80-180 mm Hg .
This is mainly due to the Myogenic theory and
Theory of tubuloglomerular feedback.

12. Tubuloglomerular Feedback

13. Hormonal mechanism