2) Renin and an enzyme called Angiotensin Converting Enzyme (ACE) act to produce the active hormone Angiotensin II from Angiotensin I at the lungs . 3) Angiotensin II is a potent vasoconstrictor; it raises blood pressure by increasing vascular resistance. Angiotensin II also stimulates the secretion of Aldosterone which increases reabsorption of Na+ and water by the kidneys. The water reabsorption increases total blood volume, which increases blood pressure.
Epinephrine & Norepinephrine
The adrenal medulla releases epinephrine and norepinephrine in response to sympathetic stimulation. These hormones increase cardiac output by increasing the rate and force of heart contractions.
Antidiuretic Hormone (ADH)
This hormone is produced in the hypothalamus and released from the posterior pituitary gland in response to dehydration or decreased blood volume. ADH also causes vasoconstriction increasing blood pressure. For this reason, ADH is called Vasopressin.
Atrial Natriuretic Peptide (ANP)
Released by cells in the atria of the heart, ANP lowers blood pressure by causing vasodilation and promoting loss of salt and water in the urine, which reduces blood volume.
E) Autoregulation of Blood Pressure
This is the ability of a tissue to automatically adjust its blood flow to match its metabolic demands.
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