Module 1 - Vasculature Definitions

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood back toward the heart.

Arterioles

Blood vessels that carry blood from arteries to capillaries.

Capillaries

Small blood vessels connecting arterioles to venules and serving as the primary site of nutrient exchange.

Venules

Blood vessels that begin collecting blood to return it to the heart.

Conducting arteries

Large/elastic arteries that are the biggest arteries, such as the aorta.

Distributing arteries

Medium/muscular arteries that distribute blood to specific organs.

Resistance arteries

Small arteries, primarily arterioles, that control the amount of blood delivered to various organs.

Capillary bed

Network of approximately 10-100 capillaries.

Precapillary sphincters

Structures within capillary beds that control blood flow into the capillaries.

Postcapillary venules

The smallest veins and vessels that are even more porous than capillaries.

Muscular venules

Venules up to 1 mm in diameter with one or two layers of smooth muscle in the tunica media.

Medium veins

Veins up to 10 mm in diameter with a thin tunica media and thick tunica externa.

Large veins

Veins greater than 10 mm in diameter.

Portal system

A circulatory route containing two capillary beds.

Blood flow

Amount of blood flowing through an organ, tissue, or blood vessel, measured in mL/min.

Perfusion

Blood flow per given volume or mass of tissue in a given time, measured in mL/min/g.

Blood pressure (BP)

Force that blood exerts against a vessel wall.

Systolic pressure

Peak arterial blood pressure during ventricular contraction.

Diastolic pressure

Minimum arterial blood pressure during ventricular relaxation between heartbeats.

Pulse pressure

Difference between systolic and diastolic pressure.

Mean arterial pressure (MAP)

Average blood pressure that most influences tissue perfusion and cardiovascular risk.

Arteriosclerosis

Stiffening of arteries caused by deterioration of elastic tissues in arterial walls.

Atherosclerosis

Buildup of lipid deposits that become plaques.

Hypertension

Chronic resting blood pressure greater than 140/90 mm Hg according to the lecture.

Hypotension

Chronic low resting blood pressure.

Autoregulation

The ability of tissues to regulate their own blood supply.

Vasoactive chemicals

Substances secreted by platelets, endothelial cells, and perivascular tissue that stimulate vasomotor responses.

Baroreflex

Automatic negative-feedback response to changes in blood pressure.

Chemoreflex

Automatic response to changes in blood chemistry.

Chemoreceptors

Receptors that detect changes in blood chemistry, especially pH and O₂ and CO₂ concentrations.