Vascular System Vocabulary Flashcards

Flashcards covering vessel structure, tunic layers, types of arteries and veins, capillaries, aneurysms, and circulatory volume statistics from Chapter 16.

Vascular System

An elaborate system of blood vessels in the body measuring more than $60,000\,\text{miles}$ long in the average adult, responsible for supplying oxygen and nutrients to tissues and removing waste products.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that return blood to the heart.

Capillaries

Microscopic exchange vessels that connect the smallest arteries to the smallest veins, where nutrients, wastes, and hormones are transferred between blood and tissues.

Vascular System Framework Diagram

A diagram illustrating arteries carrying blood away from the heart (left ventricle), veins returning blood to the heart (right ventricle), and capillaries connecting them.

Tunica Intima

The innermost layer of a blood vessel, composed of simple squamous epithelium (endothelium) continuous with the heart lining, which keeps blood flowing smoothly and secretes chemicals to dilate or constrict vessels.

Tunica Media

The thickest middle layer of a blood vessel wall, composed of smooth muscle and elastic tissue innervated by the autonomic nervous system to allow vessel diameter changes.

Tunica Externa

The outer layer of a blood vessel wall made of strong, flexible, fibrous connective tissue that supports and protects the vessel; it is the thickest layer in veins.

Endothelium

The simple squamous epithelium lining the interior surface of blood vessels and the heart.

Aneurysm

A bulge in an arterial wall caused by blood pushing against a weakened area, most commonly resulting from atherosclerosis combined with high blood pressure.

Conducting Arteries

The body's largest arteries, also called elastic arteries, which contain elastic fibers in the tunica media allowing them to expand as blood surges in and recoil when ventricles relax; examples include the aorta, common carotid artery, and subclavian artery.

Distributing Arteries

Also called muscular arteries, these smaller-diameter arteries deliver blood farther from the heart to specific organs and body areas; examples include brachial, femoral, and renal arteries.

Arterioles

The smallest arteries, also called resistance vessels, which regulate blood pressure and control organ blood entry via smooth muscle contraction in their walls.

Metarterioles

Short connecting vessels that connect arterioles to capillaries.

Capacitance Vessels

Another name for veins, referring to their high stretchability that allows them to carry varying amounts of blood with almost no change in pressure.

Large Veins

Veins formed as medium-sized veins converge, characterized by a thick tunica externa; examples include venae cavae, pulmonary veins, and internal jugular veins.

Medium-Sized Veins

Veins formed by converging venules that contain one-way valves made from endothelium to prevent backflow; examples include radial, ulnar, and saphenous veins.

Venules

The smallest, porous veins that collect blood from capillaries and exchange fluid with surrounding tissues.

Precapillary Sphincters

Smooth muscle rings located at the origin of capillary beds that open or close to regulate blood flow through the network.

Microcirculation

The flow of blood through the network of capillaries linking arterioles to venules.

Resting Blood Distribution

The condition at rest where only $4\%$ of the body's blood resides in the heart, $13\%$ of vessel blood circulates in the brain, and about $90\%$ of skeletal muscle capillaries are shut down.

Venous Blood Reservoir

The distribution pattern in which veins contain more than $60\%$ of circulating blood, compared to $11\%$ in arteries.