angina
pain caused by partial blockage of the coronary arteries by the buildup of plaque and lack of oxygen to the heart muscle
aorta
major artery of the body that takes blood away from the heart
arteriole
small vessel that connects an artery to a capillary bed
artery
blood vessel that takes blood away from the heart
atherosclerosis
buildup of fatty plaques in the coronary arteries in the heart
atrioventricular valve
one-way membranous flap of connective tissue between the atrium and the ventricle in the right side of the heart; also known as tricuspid valve
atrium
(plural: atria) chamber of the heart that receives blood from the veins and sends blood to the ventricles
bicuspid valve
(also, mitral valve; left atrioventricular valve) one-way membranous flap between the atrium and the ventricle in the left side of the heart
blood pressure (BP)
pressure of blood in the arteries that helps to push blood through the body
capillary
smallest blood vessel that allows the passage of individual blood cells and the site of diffusion of oxygen and nutrient exchange
capillary bed
large number of capillaries that converge to take blood to a particular organ or tissue
cardiac cycle
filling and emptying the heart of blood by electrical signals that cause the heart muscles to contract and relax
cardiac output
the volume of blood pumped by the heart in one minute as a product of heart rate multiplied by stroke volume
cardiomyocyte
specialized heart muscle cell that is striated but contracts involuntarily like smooth muscle
closed circulatory system
system in which the blood is separated from the bodily interstitial fluid and contained in blood vessels
coronary artery
vessel that supplies the heart tissue with blood
coronary vein
vessel that takes blood away from the heart tissue back to the chambers in the heart
diastole
relaxation phase of the cardiac cycle when the heart is relaxed and the ventricles are filling with blood
double circulation
flow of blood in two circuits: the pulmonary circuit through the lungs and the systemic circuit through the organs and body
electrocardiogram (ECG)
recording of the electrical impulses of the cardiac muscle
endocardium
innermost layer of tissue in the heart
epicardium
outermost tissue layer of the heart
gill circulation
circulatory system that is specific to animals with gills for gas exchange; the blood flows through the gills for oxygenation
hemocoel
cavity into which blood is pumped in an open circulatory system
hemolymph
mixture of blood and interstitial fluid that is found in insects and other arthropods as well as most mollusks
inferior vena cava
drains blood from the veins that come from the lower organs and the legs
interstitial fluid
fluid between cells
lymph node
specialized organ that contains a large number of macrophages that clean the lymph before the fluid is returned to the heart
myocardial infarction
(also, heart attack) complete blockage of the coronary arteries and death of the cardiac muscle tissue
myocardium
heart muscle cells that make up the middle layer and the bulk of the heart wall
open circulatory system
system in which the blood is mixed with interstitial fluid and directly covers the organs
ostium
(plural: ostia) holes between blood vessels that allow the movement of hemolymph through the body of insects, arthropods, and mollusks with open circulatory systems
pericardium
membrane layer protecting the heart; also part of the epicardium
peripheral resistance
resistance of the artery and blood vessel walls to the pressure placed on them by the force of the heart pumping
plasma
liquid component of blood that is left after the cells are removed
platelet
(also, thrombocyte) small cellular fragment that collects at wounds, cross-reacts with clotting factors, and forms a plug to prevent blood loss
precapillary sphincter
small muscle that controls blood circulation in the capillary beds
pulmocutaneous circulation
circulatory system in amphibians; the flow of blood to the lungs and the moist skin for gas exchange
pulmonary circulation
flow of blood away from the heart through the lungs where oxygenation occurs and then returns to the heart again
red blood cell
small (7–8 μm) biconcave cell without mitochondria (and in mammals without nuclei) that is packed with hemoglobin, giving the cell its red color; transports oxygen through the body
semilunar valve
membranous flap of connective tissue between the aorta and a ventricle of the heart (the aortic or pulmonary semilunar valves)
serum
plasma without the coagulation factors
sinoatrial (SA) node
the heart’s internal pacemaker; located near the wall of the right atrium
stroke volume
the volume of blood pumped into the aorta per contraction of the left ventricle
superior vena cava
drains blood from the jugular vein that comes from the brain and from the veins that come from the arms
systemic circulation
flow of blood away from the heart to the brain, liver, kidneys, stomach, and other organs, the limbs, and the muscles of the body, and then the return of this blood to the heart
systole
contraction phase of cardiac cycle when the ventricles are pumping blood into the arteries
tricuspid valve
one-way membranous flap of connective tissue between the atrium and the ventricle in the right side of the heart; also known as atrioventricular valve
unidirectional circulation
flow of blood in a single circuit; occurs in fish where the blood flows through the gills, then past the organs and the rest of the body, before returning to the heart
vasoconstriction
narrowing of a blood vessel
vasodilation
widening of a blood vessel
vein
blood vessel that brings blood back to the heart
vena cava
major vein of the body returning blood from the upper and lower parts of the body; see the superior vena cava and inferior vena cava
ventricle
(heart) large inferior chamber of the heart that pumps blood into arteries
venule
blood vessel that connects a capillary bed to a vein
white blood cell
large (30 μm) cell with nuclei of which there are many types with different roles including the protection of the body from viruses and bacteria, and cleaning up dead cells and other waste