Question

Where are mesangial cells located?
(A) In endothelium of glomerulus
(B) Between endothelium and basal lamina
(C) Infiltration slit
(D) Sub podocytic space

Answer 1

Hint: Mesangial cells are a part of the kidney's renal corpuscle. Usually mesangial cells are present in association with blood vessel lining cells.

Complete step by step answer:
Mesangial cells are found in the kidney's renal corpuscle. Renal corpuscle or Malpighian body consists of glomerulus and Bowman’s capsule. Glomerulus contains a tuft of capillaries which is formed by afferent arteriole. Afferent arteriole is a fine branch of the renal artery.
Glomerular filtration takes place through three different layers, namely
(i) Endothelium of capillaries
(ii) Epithelium of Bowman’s capsule
(iii) Basement membrane between (i) and (ii)
Mesangial cells are present at two regions –
Mesangium – Intra glomerular cells
Mesangium – Extra glomerular cells
Intraglomerular mesangial cells are present along with the endothelium of capillaries. Extra glomerular mesangial cells are present in the juxtaglomerular apparatus. Mesangial cells account for around 30% to 40% of the total cells in glomerulus. They are specialized cells which secrete an extracellular matrix known as a mesangial matrix. Mesangial matrix is rich in fibronectin and laminin which supports the glomerular capillaries.
Understanding the options one by one,
(A) In endothelium of glomerulus
This is the correct answer, because the intraglomerular mesangial cells are present in glomerulus capillary.
(B) Between endothelium and basal lamina
Podocytes are the ones which are found between endothelium and basal lamina
(C) Infiltration slit
Podocytes are the epithelial cells of Bowman’s capsule which are arranged in a tricky manner, forming a filtration slit.
(D) Sub podocytic space
Mesangial cells are not found in sub podocytic space.

Hence the correct answer is option(A)

Note: An important point is that mesangial cells are found both inside and outside glomerulus. Inside glomerulus, the mesangial cells are found in the endothelium of capillaries and outside the glomerulus, the mesangial cells are found in juxtaglomerular apparatus.