6.2 The Blood System

Artery

A blood vessel that carries blood away from the heart

Systolic

Blood pressure in the arteries during contraction of the ventricles.

Tunica intima

The innermost layer of a blood vessel

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.

Tunica externa

outer layer of a blood vessel which connects it to surrounding tissues

Vasoconstriction

Narrowing or constricting of blood vessels

Diastolic pressure

Occurs when the ventricles are relaxed; the lowest pressure against the walls of an artery

Vasodilation

Increase in diameter of a blood vessel

Pulse

Beat of the heart as felt through the walls of the arteries.

Capillaries

Microscopic vessel through which exchanges take place between the blood and cells of the body

Vein

A blood vessel that carries blood back to the heart.

Valve

A flap of tissue in the heart or a vein that prevents blood from flowing backward.

Muscle fiber

Long slender skeletal muscle cells

Elastin Fiber

A protein with elastic or springlike properties; found in large arteries and in the airways

Superior vena cava

A vein that is the second largest vein in the human body and returns blood to the right atrium of the heart from the upper half of the body.

Aorta

Branches off the left ventricle; carries oxygen rich blood to parts of the body above the heart

Pulmonary Valve

Valve positioned between the right ventricle and the pulmonary artery

Right Atrium

Receives deoxygenated blood from the body

Inferior vena cava

A vein that is the largest vein in the human body and returns blood to the right atrium of the heart from bodily parts below the diaphragm.

Left pulmonary veins

Bring oxygen-rich blood from the left lung to the left atrium

Left Atrium

Receives oxygenated blood from the lungs

Left Ventricle

Pumps oxygenated blood to the body

Interventicular septum

The curved slanting wall that separates the right and left ventricles of the heart and is composed of a muscular lower part and a thinner more membranous upper part.

Right ventricle

Pumps blood to the lungs

Sinoatrial node

Pacemaker of the heart

Myogenic

Describes muscle tissue (heart muscle) that generates its own contractions.

Pacemaker

A device that delivers electrical impulses to the heart to regulate the heartbeat

Atrioventricular (AV) node

Neurological tissue in the center of the heart that receives and amplifies the conduction of impulses from the SA node to the bundle of His

Cardiac Cycle

A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles

Medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

Cardiovascular center

Regulates the rate and force of the heartbeat and the diameter of blood vessels \n \n Located inside of the Medulla Oblongata

Epinephrine

Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline.

Coronary Artery

The artery that supplies heart tissue with blood

Angina

Chest pain resulting from myocardial ischemia