Ultrafiltration

What is ultrafiltration?

The process by which small molecules are filtered from blood into Bowmans capsule

Which small molecules are filtered into Bowmans capsule?

Water glucose mineral ions and urea

Where does blood enter the glomerulus?

Through the afferent arteriole

Where does blood leave the glomerulus?

Through the efferent arteriole

Why does the efferent arteriole maintain high hydrostatic pressure?

It is smaller than the afferent arteriole

What does high hydrostatic pressure force out of the blood?

Water and small solutes

What does the capillary endothelium contain that allows small molecules to pass through?

Pores

What is the function of the basement membrane?

It acts as a selective filter

What prevents large molecules and blood cells passing through the basement membrane?

Collagen fibres

What are podocytes?

Specialised cells in the Bowmans capsule epithelium

What are pedicels?

Extensions of podocytes that wrap around capillaries

What is the function of podocytes?

They help filter the blood

Where does filtered fluid collect?

In Bowmans capsule

What is glomerular filtrate?

The liquid part of blood that enters Bowmans capsule

Which substances are filtered into the glomerular filtrate?

Water salts glucose and urea

Which substances remain in the blood?

Blood cells platelets and proteins

Why are useful substances in the glomerular filtrate reabsorbed?

To retain essential nutrients and maintain chemical balance

What does GFR stand for?

Glomerular filtration rate

What does glomerular filtration rate measure?

The volume of glomerular filtrate formed per minute