renin-angiotensin-aldosterone system (RAAS).pptx

The renin-angiotensin-aldosterone system (RAAS) is the system of hormones, proteins, enzymes and reactions that regulate your blood pressure and blood volume on a long-term basis.

It regulates your blood pressure by increasing sodium (salt) reabsorption, water reabsorption (retention) and vascular tone (the degree to which your blood vessels constrict, or narrow).

1. RAAS (Renin-Angiotensin-Aldosterone system) BY:SURAJ SINGH BATCH:2022 PHYSIOLOGY SEMINAR

2. RAAS is a hormone system within the body that is essential for the regulation of body fluid balance it helps in long term BP regulation Introduction

3. EXTRA GLOMERULAR MESANGIAL CELL

4. Mechanism of action

5. Stimulus Decrease in Blood pressure Eg. Haemorrhage D iuretic administration c) Dehydration d) e)Hypotension f)Salt depletion

6. This is a glycoprotein synthesized in liver . Concentration increased by following hormones:- 1)Glucocorticoids 2)Thyroid hormones 3) Estrogen 4) Angiotensin II Angiotensinogen Secretion

7. Renin * It is a glycoprotein. *Secreted by Juxtaglomerular Apparatus(JGA) into afferent arteriole. *Stored in granules of JG Cells.

8. REGULATION OF RENIN An intra-renal baroreceptor mechanism that causes renin secretion to decrease when arteriolar pressure at the level of the JG cells increases and to increase the level of renin when arteriolar pressure at this level falls . M acula densa are sensitive to the concentration of  Na+ in arteriolar blood, a decrease in Na+ level cause increase in the level of renin

9. Angiotensin-converting Enzyme Angiotensin-converting Enzyme is a carboxypeptidase. it acts on angiotensin I to convert it to angiotensin II ACE Synthesized in blood vessels of lungs . Hence ,major conversion of angiotensin I to angiotensin II occurs in the lungs.

10. FUNCTIONS OF ANGIOTENSIN II Angiotensin II act on Blood vessels Adrenal cortex Posterior pituitary

11. Generalised vasoconstriction Secretion and synthesis of aldosterone from adrenal cortex  increase Na+ reabsorption. Stimulate ADH Secretion from posterior pituitary  increase solute free water reabsorption. Stimulate thirst mechanism  water intake increase Therefore angiotensin II plays a key role in the body response to hypovolemia. FUNCTIONS OF ANGIOTENSIN II

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