Human Anatomy: Blood Vessels Part 1 – Histology

These flashcards cover the vocabulary related to the structure and function of blood vessels, as discussed in the lecture on human anatomy.

Tunica adventitia

The outer layer of blood vessels, composed of connective tissue, providing outer protection and binding the vessel to surrounding structures.

Tunica media

The middle layer of blood vessels, made up of circularly arranged smooth muscle, responsible for regulating vessel diameter and lumen size.

Tunica intima

The inner layer of blood vessels, also known as endothelium, which is in direct contact with the blood and facilitates exchange of gases, nutrients, and waste products.

Arteries

Blood vessels that carry blood away from the heart; they possess all three tunics and have elastin fibers in the tunica media to allow expansion.

Arterioles

Small blood vessels that regulate blood flow to tissues; they have all three tunics and a unique structure called precapillary sphincters.

Capillaries

Tiny blood vessels with a diameter of about 8 microns, allowing for the exchange of gases, nutrients, and waste due to their thin walls and high surface area.

Continuous capillaries

The most common type of capillary, featuring tight junctions that provide selective permeability and are mainly located in muscle, connective tissue, and the nervous system.

Fenestrated capillaries

Capillaries characterized by perforated endothelial cells that allow rapid exchange of fluids and small solutes, found mainly in the kidneys and endocrine glands.

Sinusoidal capillaries

Capillaries that permit exchange of large cells and proteins, with large gaps in the basement membrane, found in the red bone marrow, liver, and spleen.

Venules

Blood vessels that collect blood from capillaries and transport it to veins, composed of three very thin tunics.

Veins

Blood vessels that bring blood back to the heart, characterized by a large lumen, thin walls, and often featuring valves to prevent backflow.

Varicose veins

Dilated and deformed veins due to poor valves and venous hypertension, often leading to discomfort or complications.

Atherosclerosis

The hardening of the arteries due to the buildup of cholesterol plaque in the vessel wall, which can lead to cardiovascular problems.