Ch. 7.8 Circulatory System Key Terms
Aortic valve
- Located between the left ventricle and the aorta.
Circulatory system
- also known as the cardiovascular system, is often referred to as the "transportation" system of the body. It consists of the heart, blood vessels, and blood. It transports nutrients and wastes, oxygen and carbon dioxide.
Left atrium
- receives oxygenated blood from the lungs.
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. It prevents blood from moving between the right and left sides of the heart.
Arrhythmias
- abnormal heart rhythms and can be mild to life threatening.
Diastole
- a brief period of rest.
Left ventricle
- pushes blood into the aorta, sending the blood to all other parts of the body. The blood in the right side of the heart is low in oxygen and high in carbon dioxide.
Plasma
- approximately 90 percent water, with many dissolved, or suspended, substances.
Systole
- a period of ventricular contraction
Arteries
- carry blood away from the heart.
Endocardium
- a smooth layer of cells that lines the inside of the heart and is continuous with the inside of blood vessels. It allows for the smooth flow of blood.
Leukocytes
- white blood cells, are not as numerous as erythrocytes. They are formed in the bone marrow and lymph tissue and usually live about 3-9 days. A normal count is 4,500-11,000 leukocytes per cubic millimeter of blood. Leukocytes can pass through capillary walls and enter body tissue. Their main function is to fight infection. Some do this by engulfing, ingesting, and destroying pathogens, or germs, by a process called phagocytosis.
Pulmonary valve
- located between the right ventricle and the pulmonary artery, a blood vessel that carries blood to the lungs.
Thrombocytes
- also called platelets, are usually described as fragments or pieces of cells because they lack nuclei and vary in shape and size. They are formed in the bone marrow and live for about 5-9 days.
Blood
- made of the fluid called plasma and formed or solid elements called blood cells
Erythrocytes
- Also referred to as red blood cells, are produced in the red bone marrow at a rate of about one million per minute. They live approximately 120 days before being broken down by the liver and spleen
Mitral valve
- located between the left atrium and left ventricle. It closes when the left ventricle is contracting, allowing blood to flow into the aorta (for transport to the body) and preventing blood from flowing back into the left atrium.
Right atrium
- receives blood as it returns from the body cells.
Tricuspid valve
- located between the right atrium and the right ventricle. It closes when the right ventricle contracts, allowing blood to flow to the lungs and preventing blood from flowing back into the right atrium.
Capillaries
- located in close proximity to almost every cell in the body. They have thin walls that contain only one layer of cells.
Hemoglobin
- Carries both oxygen and carbon dioxide. When carrying oxygen, hemoglobin gives blood its characteristic red color. When blood contains a lot of oxygen, it is bright red; when blood contains less oxygen and more carbon dioxide, it is a much darker red with a bluish cast.
Myocardium
- the muscular middle layer.
right ventricle
- receives blood from the right atrium and pumps the blood into the pulmonary artery, which carries the blood to the lungs for oxygen.
Veins
- blood vessels that carry blood back to the heart.