14.9k views
0 votes
Describe how each of the following works to regulate reabsorption and secretion, so as to affect urine volume and composition? a)renin-angiotensin system b)aldosterone c)antidiuretic hormone d)natriuretic peptides

1 Answer

3 votes

Final answer:

The regulation of kidney function and urine composition involves the renin-angiotensin system, aldosterone, antidiuretic hormone, and natriuretic peptides, which regulate reabsorption and secretion of water and electrolytes to maintain body fluid homeostasis.

Step-by-step explanation:

Endocrine Regulation of Kidney Function

The regulation of reabsorption and secretion in the kidneys is influenced by several hormones and systems that ultimately affect urine volume and composition. These include:

  • Renin-Angiotensin System: This system starts with the release of renin from the kidneys, leading to the production of angiotensin II, a vasoconstrictor that increases blood pressure and stimulates the release of aldosterone from the adrenal cortex. This causes the collecting duct to retain Na+, leading to water retention and increased blood pressure.
  • Aldosterone: It promotes Na+ reabsorption in the distal convoluted tubules (DCT) and collecting ducts, which in turn increases water reabsorption due to the osmotic gradient this creates.
  • Antidiuretic Hormone (ADH): ADH, released from the pituitary gland, promotes water recovery by the collecting ducts by stimulating the insertion of aquaporin water channels into their cell membranes, increasing the reabsorption of water.
  • Natriuretic Peptides: Released mainly from the atria of the heart, these hormones respond to increases in blood pressure by stimulating the excretion of Na+ and hence water, leading to decreased blood volume and blood pressure.

Other significant hormones involved in kidney regulation include Parathyroid Hormone (PTH), which stimulates the conversion of vitamin D to its active form and influences calcium reabsorption and phosphate excretion.

User Melchor
by
7.5k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.