Circulatory System

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

the thickest layer, the muscular middle layer

double-layered membrane, or sac that covers the outside of the heart; a lubricating fluid, pericardial fluid, fills the space between the 2 layers to prevent friction and damage to the membranes as the heart beats or contracts

A muscular wall that separates th heart into a right and left side, prevents blood from moving between the right and left sides of the heart

2 upper chambers of the heart, R atrium: receives blood as it returns from body cells &, L atrium: receives oxygenated blood from lungs

2 lower chambers of the heart; R ventricle receives blood from right atrium and pumps blood into pulmonary artery, which carries blood to lungs for oxygen; L ventricle: receives blood from the left atrium and pumps the blood into aorta for transport to body cells

located between the right atrium and ventricle, closes when R ventricle contracts, allowing blood from flowing back into R atrium

located between the right ventricle and pulmonary artery, a blood vessel that carries blood to the lungs, it closes when right ventricle has finished contracting, preventing blood from flowing back into the right ventricle

located between left atrium and left ventricle, it closes when left ventricle is contracting, allowing blood to flow into the aorta (for transport to the body) and preventing blood from flowing back into left atrium

located between left ventricle and the aorta, the largest artery in the body, closes when the left ventricle is finished contracting, allowing blood to flow into the aorta and preventing blood from flowing back into left ventricle

part of the heartbeat cycle (cardiac) cycle: a brief period of rest

part of heartbeat (cardiac) cycle: a period of ventricular contraction

group of nerve cells located in the right atrium, called “pacemaker” sends out electrical impulse that spreads out over the muscles in the atria

abnormal heart heart rhythm and can be mild to life threatening

carry blood away from the heart, aorta is the largest artery

connect arterioles with venules, the smallest veins, located in close proximity of almost every cell in the body

blood vessels that carry blood back to the heart, venules are the smallest branches of the veins

flows through the circulatory system, is called a tissue because it contains many kind of cell, made of plasma fluid and blood cells

approximately 90% percent water with many dissolved or suspended substances; blood proteins, nutrients, electrolytes/mineral salts, metabolic water products, hormones, and enzymes

red blood cells produced in the red bone marrow at a rate of about 1 million per min

complex protein composed of the protein molecule called globin and the iron compound called heme, gives blood, its red color, when carrying oxygen, present in erthrocytes

white blood cells, that are not as numerous as erthrocytes fromed in bone marrow and lymph tissue, usually live about 3-9 days, and fight infection

also called platelets, are usually described as fragments or pieces of cells because they lack nuclei and vary in shape and size, formed in bone marrow, important for blood clotting because they form a sticky plug, secrete a chemical serotonin, causes blood vessel to spasm

an inadequate number of red blood cells, hemoglobin or both. symptoms: pallor, fatigue, dyspnea, and rapid heart rate