This integrated hormonal cascade system regulates arterial blood pressure, intra-vascular volume and electrolyte balance. More broadly, it is a complex autocrine system involved in diverse processes of cellular biology and pathophysiology.
Reduced arterial blood pressure si
Renin, a proteolytic enzyme that is synthesised and stored as a precursor in granular juxtaglomerular cells in afferent arteriolar wall of glomerulus (specialised myoepithelial cells in the media). The cells respond to changes in transmural pressure gradient between afferent arteriole and interstitium. They are innervated directly by the sympathetic postganglionic unmyelinated fibres. Renin is a carboxyl-peptidase enzyme acting on plasma alpha-2-globulin angiotensinogen —
(renin substrate in plasma)
angiotensin I (10 amino acid peptide) converting enzyme (lung endothelium)
angiotensin II (8 amino acids)
| II angiotensinase (inactivation)
renal retention of vasoconstriction Na and water
Raised arterial blood pressure angiotensin III (10 amino acids) Figure 6.2 Pathway for renin-angiotensin mechanism.
Was this article helpful?