Question

Give the significance of podocyte.

Answer 1

In the kidney, the cells present in the Bowman's capsule are called podocytes. They are the outer covering of the glomerulus.

Complete answer:

Bowman's capsule aids in filtration of blood by eliminating the molecules like water, sugars and salt by retaining the molecules like proteins during the first step of formation of urine.
The cells are named as podocytes as they undergo foot processes known as pedicels.
There is a formation of slit between the capillaries when the pedicles are wrapped around the capillaries. These slits are called as slit pores, slit diaphragm or filtration slit.
The slits are lined by a slit diaphragm which contains cell surface proteins like nephrin, podocalyxin which limits the passage of macromolecules like albumin, serum etc.
The filtration of small molecules such as salts, water and glucose through these slits results in formation of ultrafiltrate in tubular fluid, which is later processed to produce urine by nephron.
The pedicles help in efficient ultrafiltration by increasing the surface area of the cells.
Podocytes aid in maintaining the basement membrane.
Podocytes have a large golgi apparatus and acute endoplasmic reticulum which results in high volume protein secretion.
Podocytes also aids in regulation of glomerular filtration rate(GFR).
The contraction in podocytes leads to the closure of the slit diaphragm .
This results in reduction of GFR by the depletion in surface area that is available for filtration.

Note: For the pedicles to function and wrap around capillaries, they require proteins like nephrin and $CD_2AP$. The variation in these proteins may lead to kidney failure.