Renal

Question 1

Renin-Angiotensin-Aldosterone system

Answer 1

A further compensatory system is activated when the BP in the kidney falls

Question 2

Hormones involved in the Regulation of renal blood flow

Answer 2

Adrenaline/Epinephrine - secreted by adrenal gland right above the kidneys, in response to sympathetic stimulation. Produces vasoconstriction leading to an increased arteriolar resistance.

Angiotensin II

Question 3

Angiotensin II causes

Answer 3

Rapid + Powerful vasoconstriction
Stimulates the adrenal zona glomerulosa to increase
aldosterone production (over hours or days), leading to
sodium and water retention.
These actions reverse hypotension that is usually responsible for the stimulation of renin release

Question 4

Low cardiac output

Answer 4

Stimulates the secretion of renin by the juxtaglomerular cells in the kidneys. In the blood active renin converts angiotensinogen (produced in the liver) to inactive angiotensin I. This goes to the lungs and encounters the angiotensin-converting enzyme (ACE) and it is converted into angiotensin II.
This then interacts with the adrenal cortex (top of the kidney) and stimulates the kidney to release aldosterone.
This interacts with the neuron in the kidney, telling it to retain water and the SVR increaces.

Question 5

Aldosterone

Answer 5

Promotes water and sodium reabsorption in the collecting duct.

Question 6

ACE inhibitors

Answer 6

Work by blocking the action of angiotensin-converting enzyme in the lungs and this causes a reduction in the conversion of angiotensin I to II. Therefore preventing Powerful vasoconstriction and subsequent hypertension.

Question 7

Describe how the renin angiotensin aldosterone system influences systemic vascular resistance

Answer 7

Baroreceptors detect changes in blood pressure which is affected by systemic vascular resistance.
When there is low blood pressure, there may be less SVR, the arterial wall is less stretched and the baroreceptors activity win decrease
Low cardiac output is detected by the baroreceptors and causes an increase in the activity of the sympathetic nervous system which causes an increase in the release of adrenaline/epinephrine and noradrenaline, this will increase HR.

Question 8

Beta blockers

Answer 8

Inhibit this process when there is excessive SVR

Work by binding to beta receptors, blocking the beta receptors and reducing the ability of adrenaline to synapse onto the myocardium of the heart, decreasing HR.
Lock and key mechanism means theres less receptors to bind on to.