Vascular System and Hepatic Portal Circulation

Critical vocabulary terms and physiological concepts related to the vascular system, liver functions, and blood pressure dynamics.

Vena cava

The body's main vein, divided into superior and inferior sections.

Superior vena cava (SVC)

The portion of the main vein that receives blood from the head, shoulders, and arms.

Inferior vena cava (IVC)

The portion of the main vein that receives blood from the lower part of the body.

Superficial veins

Veins that reside near the body surface.

Deep veins

Veins that lie deep within the body, usually alongside bones or corresponding arteries.

Hepatic veins

Veins that drain blood from the liver.

Internal jugular vein

The vein that drains most of the blood from the brain and the face; it merges into the subclavian vein.

Cephalic vein

A vein that is a frequent site for the administration of IV fluids.

Median cubital vein

The most common site used for drawing blood.

Popliteal vein

A vein that runs behind the knee.

Great saphenous vein

The longest vein in the body; it is frequently harvested for use in coronary artery bypass grafts (CABG).

CABG

Acronym for coronary artery bypass graft.

External jugular vein

A superficial vein that drains blood from the scalp, facial muscles, and other superficial structures into the subclavian vein.

Vertebral vein

The vein that drains the cervical vertebrae, spinal cord, and some neck muscles.

Hepatic portal circulation

The system where blood from digestive organs and the spleen is sent through the hepatic portal vein to the liver for processing before returning to the heart.

Sinusoids

Microscopic capillaries within the liver where portal blood is distributed.

Portal hypertension

Increased pressure in the portal vein often caused by disruptions in hepatic portal circulation.

Capillary bed

A network of capillaries that nourish a specific area and allow for nutrient and gas exchange.

Portal venous system

A configuration where one capillary bed drains into another capillary bed before the blood returns to the heart.

Hypophyseal portal system

A portal system connecting the hypothalamus and the pituitary gland for direct hormone transportation.

First pass effect

The pharmacological phenomenon where oral medicines are metabolized and potentially deactivated by the liver before reaching general circulation.

Prodrugs

Drugs designed to be taken orally that require conversion by the liver to become functional.

Pressure gradient

The difference in pressure between two structures that causes blood to flow.

Peripheral vascular resistance

The opposition to blood flow resulting from the friction of moving blood against vessel walls.

Viscosity

The thickness or stickiness of blood; greater viscosity typically slows blood flow.

Vasoconstriction

The narrowing of blood vessels which increases resistance, raises blood pressure, and decreases flow into tissues.

Vasodilation

An increase in blood vessel diameter which decreases resistance, lowers blood pressure, and increases tissue blood flow.

Angiogram

A specialized X-ray that uses dye to highlight and assess blood vessels.