Question

The hormone atrial natriuretic peptide is secreted by the atria to regulate blood pressure in a homeostatic fashion

.A. Atrial natriuretic peptide inhibits the secretion of renin and aldosterone. How would this peptide affect blood volume and blood pressure?

B. Atrial natriuretic peptide also acts to dilate blood vessels. What effect will dilating blood vessels have on blood velocity and blood pressure?

C. The body secretes atrial natriuretic peptide in response to a certain physical signal from the atria. What might that signal be? Justify your response.

Answer 1

The main hormones which regulates blood volume and blood pressure in the body are ADH, aldosterone and ANP.

Both ADH and aldosterone involve in conservation of water and salt thus maintain blood volume and blood pressure.

ADH - cause absorption of water through collecting duct of nephron thus increase blood volume. While aldisterin act on DCT and stimulate absorption of salt followed by passive absorption of water thus increase blood volume and blood pressure. While ANP act in antagonist wag to these hormone.

A) ANP inhibits secretion of ADH and Aldosterone thus cause decreased absorption of salt and water thus cause blood volume and blood pressure. Effect of ADH and aldosterone has been explained above  

B) dilating of blood vessels cause decreased resistance of blood flow and cause decreased pressure excreted by blood on vessels wall and cause decreased blood pressure and cause decreased velocity of blood.

C) secretion of ANP occur in response to high blood pressure. In presence of high blood pressure there are increase amount of blood present in right atrium. This cause stimulation of stretch receptor present in right atrium. This send signal to brain and cause release of ANP in blood.