Main Hormones that Regulate Kidneys

The Juxtaglomerular Apparatus(JGA)

The regulation of Juxtaglomerular Apparatus(JGA) is also called the Angiotensin mechanism. Whenever the blood flow in the glomerulus decreases, renin is also released from juxtaglomerular cells. By the renal sympathetic nerves renin levels are increased through a direct action on granular cells and a decrease in the flow to the macula densa. When there is increased in renal sympathetic nerve activity it causes drop in the GFR which gradually increase the water reabsorption and proximal sodium ions. This results in reduction of fluid in the macula densa which later on helps in the renin production at high level. The Juxtaglomerular apparatus responds to decrease in blood pressure.

The Renin-Angiotensin-Aldosterone System (RAAS)

Angiotensin is an enzyme, it is located in the endothelium which is used to convert angiotensin I to angiotensin II. In the cardiovascular system angiotensin II stimulates vasoconstriction. The cardiovascular system further stimulates aldosterone production in the adrenal glands which increase the sodium reabsorption in the kidneys. The RAAS is responsible for basic regulation of blood pressure.

Hypothalamus

Antidiuretic Hormone (ADH) or Vasopressin

From neurohypophysis the Antidiuretic hormone or vasopressin are released if the osmoreceptors are activated. These are activated when there is a change in blood pressure or there is an excessive loss of fluids. Antidiuretic hormone stimulates the reabsorption of water from the distal parts of the tubules hence this prevents water loss and diuresis whereas when there is sufficient body fluid these osmoreceptors are switched off and therefore the release of ADH is suppressed. This ADH causes constriction of blood vessels which results in increase of blood pressure which further increases the flow of blood in the glomerulus.

Atrial Natriuretic Peptide (ANP)

Atrial Natriuretic Peptide is a 28 amino acid peptide hormone which are located in the granules in atrial myocytes. ANP is released when there is increased blood flow in the atria of the heart. Renal tubules are inhibited from reabsorbing water and salt. The reduced sodium ion and the water level enhance the urine result, allowing the blood volume to become normal. ANP exerts moderate effects in vasodilatory which results in low blood pressure but increase in capillary pressure.

The Kidneys which are present in the human body are responsible for multiple functions in humans which include the formation of urine, water metabolism, ionic balance, and regulation of blood pressure. Therefore with the help of these kidneys, the wastes are being removed from human body. These kidneys are responsible for regulating water balance in human beings and also filtering waste and excess of these fluids from the blood.