Question

Name the hormone that regulates the heartbeat and blood pressure.

Answer 1

Following hormones regulates heartbeat and blood pressure:-

• The renin‐angiotensin‐aldosterone system of the kidneys regulates blood volume. In response to rising blood pressure, the juxtaglomerular cells in the kidneys secrete renin into the blood. Renin converts the plasma protein angiotensinogen to angiotensin I, which in turn is converted to angiotensin II by enzymes from the lungs.

Angiotensin II constricts blood vessels throughout the body (raising blood pressure by increasing resistance to blood flow). Constricted blood vessels reduce the amount of blood delivered to the kidneys, which decreases the kidneys' potential to excrete water (raising blood pressure by increasing blood volume).

• Angiotensin II stimulates the adrenal cortex to secrete aldosterone, a hormone that reduces urine output by increasing retention of water and Na + by the kidneys (raising blood pressure by increasing blood volume).
• Epinephrine and norepinephrine, hormones secreted by the adrenal medulla, raise blood pressure by increasing heart rate and the contractility of the heart muscles and by causing vasoconstriction of arteries and veins. These hormones are secreted as part of the fight‐or‐flight response.
• Antidiuretic hormone (ADH), a hormone produced by the hypothalamus and released by the posterior pituitary, raises blood pressure by stimulating the kidneys to retain water (raising blood pressure by increasing blood volume).
• Thyroid hormones raise the heart rate and contraction force.