Vascular System Key Terms and Concepts

A comprehensive vocabulary review of key terms, structures, and mechanisms related to the vascular system based on the provided lecture notes.

Anastomosis

A natural connection between two vessels.

Aneurysm

Bulge in an arterial wall that results when a portion of the arterial wall weakens.

Arteries

Blood vessels that carry blood away from the heart.

Arteriole

The smallest arteries; also called resistance vessels.

Baroreceptors

Sensory nerve endings in the aortic arch and carotid arteries that sense changes in pressure.

Capacitance vessels

Another name for veins because of their great capacity for storing blood.

Capillary

Microscopic vessels that link arterioles to venules; site where nutrients, wastes, and hormones are exchanged between blood and tissue.

Circle of Willis

Circle of arteries at the base of the brain.

Colloid osmotic pressure

Process whereby albumin in the blood pulls tissue fluid into capillaries.

Conducting arteries

The body's largest arteries; also called elastic arteries.

Diastolic pressure

Pressure within arteries when the ventricle relaxes.

Diffusion

Process by which molecules of a substance move from an area of higher to lower concentration.

Distributing arteries

Carry blood to specific organs and tissues; also called muscular arteries.

Edema

Condition characterized by an excess of fluid in the tissues.

Elastic arteries

The body's largest arteries; also called conducting arteries; expand as blood surges into them.

Filtration

Process of removing particles from a solution by allowing the liquid portion to pass through a membrane.

Hypertension

Blood pressure consistently higher than $140\,mm\,Hg$ systolic over $90\,mm\,Hg$ diastolic.

Metarterioles

Short vessels that connect arterioles to capillaries.

Muscular arteries

Also called distributing arteries.

Peripheral resistance

Resistance to blood flow resulting from the friction of the blood against the walls of the vessels.

Portal system

System of vessels in which blood passes through a capillary network, a large vessel, and then another capillary network before returning to the systemic circulation.

Pressure gradient

Difference in pressure between two structures.

Resistance vessels

Arterioles; help regulate blood pressure and control how much blood enters an organ.

Respiratory pump

The process by which breathing promotes the flow of venous blood in the thoracic and abdominal cavities, where inhalation lowers chest pressure, raises abdominal pressure, squeezes the inferior vena cava, and draws blood toward the heart.

Sinusoid

Large, permeable capillary found in organs such as the liver, spleen, and bone marrow that allows for the passage of large cells and proteins.

Skeletal muscle pump

Process by which the contraction of skeletal muscles aids in venous return by massaging leg veins to propel blood toward the heart while valve flaps prevent backward flow.

Systolic pressure

Pressure in arteries when the ventricle ejects blood.

Tunica externa

Outer layer of blood vessels; composed of strong, flexible, fibrous connective tissue.

Tunica intima

Innermost layer of blood vessels; consists of simple squamous epithelium.

Tunica media

Middle layer of blood vessels; composed of smooth muscle and elastic tissue.

Vasoconstriction

Reduction in the diameter of a vessel.

Vasodilation

Increase in the diameter of a vessel.

Vasomotion

The process by which blood vessels adjust their diameter.

Vasomotor center

Area in the medulla of the brain that sends impulses to alter blood vessel diameter and therefore blood pressure.

Veins

Blood vessels that return blood to the heart; called capacitance vessels because of their capacity for storing blood.

Vena cava

The body's chief vein, which serves to return blood to the heart.

Venule

The smallest veins; serve to collect blood from the capillaries.