Renin-Angiotensin System

Negative Feedback

increased blood volume increases blood pressure increasing blood flow to kidneys -decreases renin release from kidneys to stop compensatory mechanisms

2. Ang-I in Lungs

Ang-I reaches lungs converted into angiotensin II by angiotensin converting enzyme

3. Ang II Function

Ang-II reacts with specific ang-II receptors on blood vessels causing intense vasoconstriction -vasoconstriction -aldosterone seceretion -blood volume

Blood volume

Na rich blood stimulates hypothalamus osmoreceptors to release ADH -stimulates water retention increasing blood volume -increased vascular blood volume increasing arterial blood pressure and blood flow to kidneys

Aldosterone Secretion

adrenal cortex secretion of aldosterone -increase Na reabsorption at kidney tubule along with water

Renin-Angiotensin System

central role in blood pressure regulation stimulated by -reduced arterial blood pressure -fall in extracellular fluid -reduced blood flow to kidneys

1. Low Blood Flow to Kidneys

juxtaglomerular cells release renin enzyme into blood stream -renin arrives at liver reacts with inactive angiotensinogen to form active angiotensin I

Vasoconstriction

of arterioles increasing peripheral vascular resistance + blood pressure