Page 12 - G43 ASSIGNMENT

The renin-angiotensin system is mediated by the renal system. Renin is a molecule released from the
juxtaglomerular apparatus in response to under perfusion; renin may also be released via activation of the
sympathetic nervous system. Renin converts angiotensinogen into angiotensin I, which subsequently
converts into angiotensin II which acts as a vasoconstrictor on blood vessels, thus causing a rise in blood
pressure.[2][3][8]

The autonomic nervous system causes both vasoconstriction and vasodilation. Alpha-1 receptor
activation causes vasoconstriction, and beta-2 receptor activation causes vasodilation.[2][3]
The endothelium, itself, can modulate blood pressure. The endothelium may release nitrous oxide
(vasodilation) or endothelin (vasoconstrictor).[2][3]
Several molecules have been found to place a role in blood pressure but have an unclear significance on
the control of hypertension. Examples of these molecules are bradykinin, thromboxane, and atrial
natriuretic peptide (ANP).[2][3]
References

Webb RC, Smooth muscle contraction and relaxation. Advances in physiology education. 2003 Dec; [PubMed PMID: 14627618]
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Beevers G,Lip GY,O'Brien E, ABC of hypertension: The pathophysiology of hypertension. BMJ (Clinical research ed.). 2001 Apr
[2]
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Bolívar JJ, Essential hypertension: an approach to its etiology and neurogenic pathophysiology. International journal of hypertension.
[3]
2013; [PubMed PMID: 24386559]

Schindler C,Dobrev D,Grossmann M,Francke K,Pittrow D,Kirch W, Mechanisms of beta-adrenergic receptor-mediated venodilation in
[4]
humans. Clinical pharmacology and therapeutics. 2004 Jan; [PubMed PMID: 14749691]

Costa F,Biaggioni I, Role of nitric oxide in adenosine-induced vasodilation in humans. Hypertension (Dallas, Tex. : 1979). 1998
[5]
May; [PubMed PMID: 9576114]

Moran D,Epstein Y,Keren G,Laor A,Sherez J,Shapiro Y, Calculation of mean arterial pressure during exercise as a function of heart rate.
[6]
Applied human science : journal of physiological anthropology. 1995 Nov; [PubMed PMID: 8591100]

Rodriguez R,Cucci M,Kane S,Fernandez E,Benken S, Novel Vasopressors in the Treatment of Vasodilatory Shock: A Systematic Review
[7]
of Angiotensin II, Selepressin, and Terlipressin. Journal of intensive care medicine. 2018 Dec 18 [PubMed PMID: 30563433]

Gargiulo R,Suhail F,Lerma EV, Hypertension and chronic kidney disease. Disease-a-month : DM. 2015 Sep; [PubMed
[8]
PMID: 26328515]

Rodriguez MA,Kumar SK,De Caro M, Hypertensive crisis. Cardiology in review. 2010 Mar-Apr; [PubMed PMID: 20160537]
[9]

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