How does glomerular filtration occur?

Question

David Arnold · Accepted Answer

Blood pressure forces the fluid in the blood to be filtered across the capillaries of the glomerulus.

The Process of Filtration

The formation of urine begins with the process of filtration.

The Bowman's capsule is the filtration unit of the glomerulus.

Blood enters the glomerulus through the afferent arteriole and leaves through the efferent arteriole.

The pressure of the blood inside the glomerulus is increased because the afferent arteriole has a larger diameter than the efferent arteriole.

This increased pressure helps to force the following components out of the glomerular capillaries:

Most of the water
Almost all of the salts
Almost all of the glucose
Almost all of the urea
The water and salts pass into the Bowman's capsule as the glomerular filtrate.

Blood cells and plasma proteins are too large to pass through the pores.

How It Happens

The glomerular capillaries contain pores (fenestrae) and filtration slits that allow the solutes to pass through.

Kai Andersen · Answer

undefined Glomerular filtration occurs in the kidneys where blood is filtered across the walls of the glomerular capillaries into the Bowman's capsule. This process is driven by the pressure gradient between the blood in the glomerular capillaries and the fluid in the Bowman's capsule, known as the glomerular filtration rate (GFR). The GFR is regulated by factors such as blood pressure, blood volume, and the constriction or dilation of the afferent and efferent arterioles leading into and out of the glomerulus.