Ch. 7.8 Circulatory System Key Terms
Aortic valve
Aortic valve: A one-way valve located between the left ventricle and the aorta. It closes to prevent blood from flowing back into the left ventricle.
Arrhythmias
Arrhythmias: Abnormal heart rhythms resulting from interference with the heart's normal electrical conduction pattern.
Arteries
Arteries: Blood vessels that carry blood away from the heart. They are muscular and elastic, receiving blood pumped from the heart.
Blood
Blood: The fluid tissue of the circulatory system, composed of plasma and blood cells, which transports oxygen, nutrients, wastes, and hormones.
Capillaries
Capillaries: Tiny, thin-walled blood vessels that connect arterioles and venules. They are the site for the exchange of gases and nutrients between blood and body cells.
Circulatory system
Circulatory system (Cardiovascular system): The body's "transportation" system, consisting of the heart, blood vessels, and blood.
Diastole
Diastole: The brief period of rest in the cardiac cycle when the atria relax and the chambers fill with blood.
Endocardium
Endocardium: The smooth, innermost layer of cells lining the inside of the heart and continuous with the blood vessels, ensuring smooth blood flow.
Erythrocytes
Erythrocytes (Red blood cells): Cells produced in the red bone marrow that contain hemoglobin and are primarily responsible for carrying oxygen.
Hemoglobin
Hemoglobin: A complex protein in erythrocytes that contains iron and carries oxygen and carbon dioxide.
Left atrium
Left atrium: The upper left chamber of the heart that receives oxygenated blood from the lungs.
Left ventricle
Left ventricle: The lower left chamber of the heart that pumps oxygenated blood into the aorta for transport to the body.
Leukocytes
Leukocytes (White blood cells): Cells formed in bone marrow and lymph tissue whose main function is to fight infection (e.g., through phagocytosis and antibody development).
Mitral valve
Mitral valve: A one-way valve located between the left atrium and left ventricle. It closes to prevent blood from flowing back into the left atrium during contraction.
Myocardium
Myocardium: The thick, muscular middle layer of the heart tissue responsible for the pumping action (contraction).
Pericardium
Pericardium: A double-layered membrane, or sac, that covers the outside of the heart, containing fluid to prevent friction.
Plasma
Plasma: The fluid portion of blood (about 90% water) that contains dissolved substances like proteins, nutrients, and electrolytes.
Pulmonary valve
Pulmonary valve: A one-way valve located between the right ventricle and the pulmonary artery. It closes to prevent blood from flowing back into the right ventricle.
Right atrium
Right atrium: The upper right chamber of the heart that receives deoxygenated blood returning from the body.
Right ventricle
Right ventricle: The lower right chamber of the heart that pumps deoxygenated blood into the pulmonary artery to the lungs for oxygenation.
Septum
Septum: A muscular wall that separates the right and left sides of the heart, preventing blood from moving between the two sides.
Systole
Systole: The period of ventricular contraction in the cardiac cycle when blood is pushed out of the heart.
Thrombocytes
Thrombocytes (Platelets): Fragments of cells that are vital for the clotting process to stop bleeding.
Tricuspid valve
Tricuspid valve: A one-way valve located between the right atrium and the right ventricle. It closes to prevent blood from flowing back into the right atrium during contraction.
Veins
Veins: Blood vessels that carry blood back to the heart. Most contain valves to prevent the backward flow of blood.