THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -Renin is the first and rate-limiting step of the renin-angiotensin system. The exclusive source of renin in the circulation are the juxtaglomerular cells of the kidney, which line the afferent arterioles at the entrance of the glomeruli. Normally, renin production by these cells suffices to maintain homeostasis.

Detailed explanation-2: -Juxtaglomerular cells, in the terminal afferent arteriole of the kidneys, are the major source of circulating renin. Renin is synthesized as pre-prorenin, which is converted into prorenin after removal of the signal peptide during transfer to the endoplasmic reticulum.