BLOOD PRESSURE

Baroreceptor Reflex

A neurally mediated reflex that regulates blood pressure in the short term.

Baroreceptors

Stretch receptors located in the walls of the aorta and carotid arteries.

Where is the cardiovascular center of the brain located?

It is located in the medulla.

What is the net effect of increased parasympathetic and decreased sympathetic activity?

Decreased heart rate and systemic vasodilation, which lowers blood pressure.

Vasodilation

The dilation of blood vessels that increases the flow area and decreases systemic vascular resistance.

Renin-Angiotensin-Aldosterone System (RAAS)

A hormonal mechanism for regulating blood pressure that is slower than the baroreceptor reflex.

Juxtaglomerular cells

Cells in the kidneys that release renin when blood pressure falls.

What is the function of Renin in the RAAS pathway?

Renin converts angiotensinogen, produced by the liver, into angiotensin I.

Angiotensin-Converting Enzyme (ACE)

The enzyme that converts Angiotensin I into the active hormone Angiotensin II.

What are the three main effects of Angiotensin II?

It causes systemic vasoconstriction and stimulates the release of aldosterone and Antidiuretic Hormone (ADH).

How do Aldosterone and ADH increase blood pressure?

They cause the kidneys to retain sodium and water, which increases blood volume and cardiac output.