EMT Course Chapter 6 - The Human Body - Cardiovascular/Circulatory System

The Human Body - Cardiovascular/Circulatory System

Systemic vascular resistance

The resistance that blood must overcome to be able to move within the blood vessels; related to the amount of dilation or constriction in the blood vessel.

Hypoperfusion

A condition in which the circulatory system fails to provide sufficient circulation to maintain normal cellular function; also called shock.

Tunica media

The middle and thickest layer of tissue of a blood vessel wall, composed of elastic tissue and smooth muscle cells that allow the vessel to expand or contract in response to changes in blood pressure and tissue demand.

Carotid artery

The major artery that supplies blood to the head and brain.

Chordae tendineae

Thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting.

Inferior vena cava

One of the two largest veins in the body; carries blood from the lower extremities and the pelvis and the abdominal organs to the heart.

Hypercapnia

An abnormally high level of carbon dioxide in the bloodstream; also called hypercarbia.

Dorsalis pedis artery

The artery on the anterior surface of the foot between the first and second metatarsals.

Blood pressure

The pressure that the blood exerts against the walls of the arteries as it passes through them.

Aorta

The main artery leaving the left side of the heart and carrying freshly oxygenated blood to the body.

Cardiac muscle

The heart muscle.

Pulmonary veins

The four veins that return oxygenated blood from the lungs to the left atrium of the heart.

Platelets

Tiny, disc-shaped elements that are much smaller than the cells; they are essential in the initial formation of a blood clot, the mechanism that stops bleeding.

Arterioles

The smallest branches of arteries leading to the vast network of capillaries.

Pulse

The wave of pressure created as the heart contracts and forces blood out the left ventricle and into the major arteries.

Oncotic pressure

The pressure of water to move, typically into the capillary, as the result of the presence of plasma proteins.

Heart rate

The number of heartbeats during a specific time (usually 1 minute).

Cardiac output

A measure of the volume of blood circulated by the heart in 1 minute, calculated by multiplying the stroke volume by the heart rate.

Red blood cells

Cells that carry oxygen to the body's tissues; also called erythrocytes.

Hemoglobin

An oxygen-carrying protein found in red blood cells.

Sphygmomanometer

A device used to measure blood pressure.

Posterior tibial artery

The artery just behind the medial malleolus; supplies blood to the foot.

Shock

A condition in which the circulatory system fails to provide sufficient circulation to maintain normal cellular functions; also called hypoperfusion.

Circulatory system

The complex arrangement of connected tubes, including the arteries, arterioles, capillaries, venules, and veins, that moves blood, oxygen, nutrients, carbon dioxide, and cellular waste throughout the body.

Pulmonary artery

The major artery leading from the right ventricle of the heart to the lungs; carries oxygen-poor blood.

Stroke volume

The volume of blood pumped forward with each ventricular contraction.

Systole

The contraction, or period of contraction, of the heart, especially that of the ventricles.

Hydrostatic pressure

The pressure of water against the walls of its container.

White blood cells

Blood cells that have a role in the body's immune defense mechanisms against infection; also called leukocytes.

Superior vena cava

One of the two largest veins in the body; carries blood from the upper extremities, head, neck, and chest into the heart.

Myocardium

The heart muscle.

Atrium

One of the two upper chambers of the heart.

Pulmonary circulation

The flow of blood from the right ventricle through the pulmonary arteries and all of their branches and capillaries in the lungs and back to the left atrium through the venules and pulmonary veins; also called the lesser circulation.

Brachial artery

The major vessel in the upper extremities that supplies blood to the arm.

Femoral artery

The major artery of the thigh, a continuation of the external iliac artery. It supplies blood to the lower abdominal wall, external genitalia, and legs. It can be palpated in the groin area.

Perfusion

The flow of blood through body tissues and vessels.

Ventricle

One of the two lower chambers of the heart.

Capillary vessels

The tiny blood vessels between the arterioles and venules that permit transfer of oxygen, carbon dioxide, nutrients, and waste between body tissues and the blood.

Plasma

A sticky, yellow fluid that carries the blood cells and nutrients and transports cellular waste material to the organs of excretion.

Systemic circulation

The portion of the circulatory system outside of the heart and lungs.

Diastole

The relaxation, or period of relaxation, of the heart, especially of the ventricles.

Heart

A hollow muscular organ that pumps blood throughout the body.

Radial artery

The major artery in the forearm; it is palpable at the wrist on the thumb side.