Vessels and Circulation

Flashcards covering key vocabulary and concepts related to blood vessels and circulation.

Tunica

Each of the three distinct layers of blood vessels.

Adventicia

The outermost layer of a blood vessel, also known as tunica adventicia or tunica externa.

Media

The middle layer of the blood vessel wall, primarily consisting of smooth muscles.

Inima

The innermost layer of a blood vessel, composed of endothelium and an underlying areolar layer.

Lumen

The open space within an artery or vein through which blood flows.

Vasodilation

The relaxation of smooth muscles in blood vessels, leading to an increased lumen diameter.

Vasoconstriction

The contraction of smooth muscles in blood vessels, leading to a decreased lumen diameter.

Capillaries

The smallest and thinnest blood vessels, optimized for nutrient and gas exchange.

Elastic arteries

The largest arteries closest to the heart, designed to tolerate pressure changes.

Muscular arteries

Arteries with thicker walls and more smooth muscles, regulating blood flow to specific areas.

Venules

The smallest veins that collect blood directly from capillaries.

Valves

Structures in veins that prevent backflow of blood, especially in limbs.

Hepatic portal system

A system that directs blood from digestive organs to the liver for processing.

Circle of Willis

A critical arterial circle at the base of the brain that provides collateral circulation.

Aneurism

An enlarged blood vessel that forms when its wall weakens and balloons outwards.

Fetal circulation

The circulation system in a fetus, relying on the placenta for oxygen and nutrients.

Umbilical arteries

Arteries that carry mixed blood from the fetal heart to the placenta.

Umbilical veins

Veins that carry oxygenated blood from the placenta into the fetal heart.

Age-related changes

Changes in the cardiovascular system as individuals age, involving reduced efficiency and elasticity.

Blood pooling

Accumulation of blood in veins due to inefficient valves, often associated with aging.

Cardiac output

The volume of blood the heart pumps per minute, which may decrease with age.

Elasticity loss

Diminished ability of blood vessels to constrict and dilate, common in aging.