Question

-Explain how the kidney and small intestine assists in the regulation of cardiovascular functions such as blood pressure, blood volume, or blood solute concentration. Describe how these organs use specific hormones to control blood concentrations and what effects it has on other systems. As you mention the specific hormones make sure to mention where they are released from (specific region within the organ), what triggers their release and the direct effects they have on the blood and body functions. Lastly mention what would happen if the small intestine were removed or if the kidneys were impaired (disease or donation).

Answer 1

Kidneys and intestine both help in maintaining blood pressure and blood volume through absorption of sodium and water.
When the blood volume and blood pressure drops, kidneys release renin which causes conversion of angiotensinogen in liver to angiotensin l. Angiotensin l is further converted to angiotensin ll in the presence of angiotensinogen converting enzyme. Angiotensin ll causes release of aldosterone from adrenal gland. Aldosterone acts on the renal tubules of kidney to increase reabsorption of sodium and water. This increases the blood volume and blood pressure.
If the kidney does not function properly it can results in loss of too much salt and water loss. This causes drop in blood volume and blood pressure.

In small intestine many salt sensors are present that gets activated when salt enters the intestine and result in sodium and fluid absorption.
Aldosterone acts on small intestine to cause absorption or sodium and water.
In malfunctioning small intestine absorption of sodium and water are impaired resulting in dehydration and low BP.