Properties of Arteries

Part two in Components of The Circulatory System explores the structure and function of the blood vessels called arteries.
Researchers studying a rare form of hypertension has identified the mechanism by which they believe a protein complex in the kidney operates as a master switch that regulates blood pressure, a finding that has broad implications for the treatment of more common forms of hypertension.
Our blood pressure is regulated from minute to minute by nerves.
Another example of this reflex occurs when you suddenly sit or stand up after lying down. Gravity pulls the blood downward, lowering the blood pressure in the carotid sinus in your neck. If the carotid sinus reflex didn’t act promptly, sending out nerve impulses (over sympathetic nerves) to increase heart output and constrict the arterioles, you would faint from the decreased flow of blood to your head.
Increased sympathetic nervous system activity can also result from the psychological stress caused by our reaction to unpleasant situations. In obese people, the stimulation of sympathetic nerves by elevated insulin levels may be a compensatory mechanism to limit weight gain.
(hotlookinfo.org.ua)