There are many factors that affect glomerular filtration. It is defined as the blood filtration means of removing the waste products from the blood in the specifically glomerulus of nephron.
In this, glomeruls there are many factors that directly or indirectly affect this filtration process,
Blood pressure
In its simplest, Blood enters into the glomerulus via afferent arteriole and exit via efferent arteriole. There is difference between this two blood pressure. This causes filtration.
As, simple, when the blood pressure increases, GFR increase. And when blood pressure decreases GFR also reduce. In simple, It is called as glomerular blood hydrostatic pressure, the blood pressure exterted on the golerular capillaries.
Afferent & Efferent arteriole
See, blood enters via afferent arteriole. If there is dilation of vessel then more blood will enter and GFR increases, on the other hand, if there is low blood enters due to vasoconstriction GFR will decreases.
Efferent arteriole mild contraction causes GFR increases, because pressure will increases. But in long or chronic contraction GFR decreases, because the kidney will recieve less amount of blood.
Filtration area
It means how much area is there for filtration purpose. Normally there is sufficient surface area, but in case of kidney diseases, or physiological changes, age related changes, this area get reduced and then GFR decreases.
So, If surface are is bigger then GFR will increase and vice versa.
Permeability of the filtration area
It means, if the area or vessels are good permeable, then more easily the filtration process occurs. If it has scars or not good permeable then the GFR decrease.
Nervous system
During stress and excersise, sympathatic nervous system causes vasoconstriction. Due to this, less blood supply is reach to the kidney resulting in decreasing GFR.
Age Factor
Age is also responsible for GFR. Healthy adult has GFR range from 90 to 120 mL/min. Older person naturally have decrease GFR then the young person.
Hormones
Hormones like angiotensin II, Atrial natriuretic peptide are responsible for GFR maintainence during low blood pressure and high water and sodium content in blood.
Angiotensin II works when body has low blood pressure. It constricts the efferent arteriole that further increases blood pressure next increase GFR.
When there is high amount of sodium and water, atrial natriuretic peptide (ANP) hormone starts dilating afferent arteriole, resulting in the increasing GFR.
Other factors that affect GFR are,
- Hydration status
- Drugs
- Diseases
A good hydration keeps normal GFR. Use of medicines and diseases influenced the GFR.