A sudden change in the blood pressure is responded to by the nervous system, but long term control is managed by hormones. Low blood pressure prompts the kidneys to secrete renin. Renin generates angiotensin, which constricts arteries and raises blood pressure. The supra-renal glands, the pituitary gland and heart too, respond to low or high blood pressure by secreting aldosterone, ADH (anti-diuretic hormone), and natriuretic hormone respectively. These hormones alter the amount of fluid excreted by the kidney, which affects the volume of blood in the body, thus, causing change in blood pressure.
- ADH: Promotes water retention by kidneys, which raises blood pressure.
- Pituitary gland: Hypothalamus produces ADH, which is stored in pituitary gland and is secreted when blood pressure falls.
- Natriuretic hormone: Acts on kidneys to lower blood pressure by inhibiting renin secretion and promoting excretion of sodium and water.
- Heart: Elevated blood pressure stretches atria of heart. It stimulates atrial endocrine cells to produce natriuretic hormone.
- Supra-renal glands – it produces aldosterone when stimulated by angiotensin, which is activated by renin from kidneys.
- Kidney: when suffering from low blood pressure, it leads to reduced blood flow through kidneys and stimulates them to produce the hormone renin.
- Aldosterone: it causes kidneys to retain sodium and water. It also increases amount of fluid in the body and raises blood pressure.
- Renin: it activates angiotensin in arteries.