Structure and Function of Blood Vessels

These flashcards cover key vocabulary and definitions related to the structure and function of blood vessels, blood flow, and relevant clinical concepts.

Blood Vessels

Form a closed delivery system transporting blood to and from all body tissues.

Arteries

Carry blood away from the heart.

Veins

Carry blood toward the heart.

Capillaries

Sites of exchange between blood and tissues.

Tunica intima

Innermost layer of blood vessels; composed of endothelium and subendothelial connective tissue.

Tunica media

Middle layer of blood vessels containing smooth muscle and elastic fibers; responsible for vasoconstriction and vasodilation.

Tunica externa (adventitia)

Outer layer of blood vessels composed of connective tissue for structural support.

Elastic arteries

Largest arteries (e.g., aorta) with high elastic fiber content allowing stretch and recoil.

Muscular arteries

Medium-sized arteries with more smooth muscle for precise control of blood distribution.

Arterioles

Smallest arteries, regulators of blood flow into capillary beds.

Continuous capillaries

Most common capillaries with tight junctions limiting fluid movement.

Fenestrated capillaries

Capillaries with pores for increased permeability, found in kidneys and small intestine.

Sinusoid capillaries

Capillaries with large gaps for passage of cells and large molecules.

Vasoconstriction

Decrease in lumen diameter of blood vessels, increasing resistance and blood pressure.

Vasodilation

Increase in lumen diameter of blood vessels, reducing resistance and blood pressure.

Atherosclerosis

Buildup of plaque in arterial walls, reducing blood flow.

Varicose veins

Incompetent venous valves leading to pooling of blood.

Aneurysm

Localized dilation of an artery due to wall weakness.

Cardiac output (CO)

Volume of blood pumped by the heart per minute.

Blood pressure (BP)

Force exerted by blood on vessel walls.

Resistance (R)

Opposition to blood flow, mainly due to vessel diameter.

Mean arterial pressure (MAP)

Average pressure driving blood flow to tissues.

Short-term regulation

Neural and hormonal mechanisms adjusting vessel diameter and heart rate for immediate demands.

Hypertension

Chronically elevated blood pressure increasing the risk for heart disease and stroke.

Hypotension

Abnormally low blood pressure leading to inadequate tissue perfusion.

Systemic circulation

Delivers oxygenated blood to tissues and returns deoxygenated blood to the heart.

Pulmonary circulation

Carries blood between the heart and lungs for gas exchange.

Coronary circulation

Supplies myocardium; blockage can lead to myocardial infarction.

Cerebral circulation

Provides blood to the brain, including the Circle of Willis for redundancy.

Hepatic portal circulation

Directs nutrient-rich blood from digestive organs to the liver.

Anastomoses

Alternate pathways for blood flow, important for maintaining perfusion if a vessel is blocked.