Ch. 7.8 Circulatory System Key Terms
Ch. 7.8 Circulatory System Key Terms
The valve that prevents blood from flowing back into the left ventricle after it has been pumped into the aorta.
6. Circulatory System
Also known as the cardiovascular system, it is often referred to as the "transportation" system of the body. It consists of the heart, blood vessels, and blood.
Left Atrium
The upper left chamber of the heart that receives oxygenated blood from the lungs and pumps it to the left ventricle.
Pericardium
A double-layered membrane, or sac, that covers the outside of the heart.
Septum
A muscular wall that separates the heart into a right side and a left side, preventing the mixing of blood.
Arrhythmias
Irregular or abnormal heart rhythms that occur when something interferes with the normal electrical conduction pattern of the heart.
Diastole
The period of ventricular relaxation when the atria are filling, and blood is flowing into the ventricles (part of the cardiac cycle).
Left Ventricle
The lower left chamber of the heart that pumps oxygenated blood into the aorta (and the rest of the body).
Plasma
The liquid part of the blood, composed mainly of water (about 90 percent) with many dissolved or suspended substances, including proteins, nutrients, salts, hormones, and waste products.
Systole
The period of ventricular contraction when the ventricles forcefully push blood out into the arteries (part of the cardiac cycle).
Arteries
Blood vessels that carry blood away from the heart; the aorta is the largest artery in the body and carries blood from the left ventricle. Arteries are more muscular and elastic than veins.
Endocardium
The smooth inner layer of cells that lines the inside of the heart and is continuous with the inside of blood vessels.
Leukocytes
White blood cells (WBCs), which are not as numerous as erythrocytes. Their main function is to fight infection by engulfing, ingesting, or destroying pathogens, or by creating antibodies.
Pulmonary Valve
The valve located between the right ventricle and the pulmonary artery; it prevents blood from flowing back into the right ventricle.
Thrombocytes
Also called platelets, these are cell fragments that play a vital role in the clotting of blood.
Blood
The fluid that flows through the circulatory system, often called a tissue, composed of plasma and formed elements (red cells, white cells, and platelets). It transports oxygen, nutrients, hormones, and waste products.
Erythrocytes
Red blood cells (RBCs), produced in the red bone marrow, which contain hemoglobin to carry oxygen.
Mitral Valve
The valve located between the left atrium and left ventricle; it prevents blood from flowing back into the left atrium when the left ventricle contracts.
Right Atrium
The upper right chamber of the heart that receives deoxygenated blood from the body via the superior and inferior vena cava.
Tricuspid Valve
The valve located between the right atrium and right ventricle; it prevents blood from flowing back into the right atrium.
Capillaries
Tiny blood vessels that connect arterioles with venules; they have thin walls (only one layer of cells) allowing for the exchange of substances between blood and body cells.
Hemoglobin
A complex protein compound contained in erythrocytes that carries both oxygen and carbon dioxide.
Myocardium
The muscular middle layer of the heart.
Right Ventricle
The lower right chamber of the heart that pumps deoxygenated blood into the pulmonary artery (to the lungs).
Veins
Blood vessels that carry blood toward the heart. They often contain valves to prevent the backward flow of blood.