Cardiovascular System

mediastinum

the middle cavity of the thoracic cavity where the heart is located

base

superior end of the heart that points toward the right shoulder

apex

inferior end of the heart that points toward the left hip and rests on the diaphragm

pericardium

serous membrane that surrounds the heart; also called the pericardial sac

epicardium

outer layer of the heart wall; visceral pericardium

myocardium

thick muscular layer of the heart wall that contracts

endocardium

layer of the heart wall that lines the heart chambers

coronary circulation

blood vessels that supply and drain the myocardium of the heart

atria

upper chambers that receive blood

ventricles

lower chambers that discharge blood

interventricular septum

septum that divides the heart longitudinally between the ventricles

interatrial septum

septum that divides the heart longitudinally between the atria

atrioventricular valves

valves that control the flow of blood between the atria and ventricles

semilunar valves

valves that control the flow of blood between the ventricle and the large vessels that exit the heart

chordae tendineae

tendinous cords that anchor the Av valves to prevent them from blowing back up into the atria during ventricular contraction

pulmonary circulation

blood flow from the heart to the lungs and back to the heart

systemic circulation

blood flow from the heart to the body and back to the heart

intrinsic conduction system

electrical system of the heart that sets the basic rhythm; composed of SA node, AV node, bundle of His, R/L bundle branches, and Purkinje Fibers

sinoatrial node

starts each heartbeat; also called the pacemaker

systole

refers to contraction of the ventricles

diastole

refers to relaxation of he ventricle

cardiac cycle

includes all the event in heartbeat which includes the contraction and relaxation of both atria and ventricles

electrocardiogram

a recording of the flow of electrical impulses that travel through the heart

tachycardia

rapid heart rate; over 100 bpm

bradycardia

slow heart rate; fewer than 60 bpm

cardiac output

the amount of blood pumped out by each ventricle in one minute; heart rate x stroke volume

artery

thick-walled vessel that carries blood away from the heart

vein

thin-walled vessel that carries blood toward the heart; large veins have valves to prevent backflow

capillary

tiny vessel that allows for diffusion of substances between the blood and cells

Circle of Willis

circle of connecting blood vessels that protects the brain by providing more than one route for blood

hepatic portal circulation

carriers blood from digestive organs and the spleen to the liver to be processed before entering systemic circulation

umbilical arteries

carries nutrients and oxygen from the placenta to the fetus

umbilical arteries

carries waste and carbon dioxide from the fetus to the placenta

pulse

a measure of heart rate y counting the pressure waves created by contraction of the ventricles; can be felt in arteries close to the body surface

blood pressure

the pressure of blood pushing against the inner walls of blood vessels; expressed as a fraction with systolic pressure over diastolic pressure

hypertension

high blood pressure higher than 120/80; often caused by smoking, obesity, and lack of exercise

coronary artery

when blood flow through coronary arteries is limited due to build up of plaque

atherosclerosis

a narrowing of any arteries of the body due to an accumulation of plaque

myocardial infarction

occurs when blood flow is blocked to an area of the heart muscle; heart attack

ischemic stroke

occurs when blood flow is blocked to an area of the brain due to a blood clot

hemorrhagic stroke

occurs when there is bleeding on the brain due to a broken blood vessel

arrhythmia

irregular heart rate or heart rhythm; may be corrected with a pacemaker

cardiomyopathy

disease of the heart muscle that makes it harder to pump blood; the left ventricle wall or chamber man enlarge

endocarditis

an infection of the lining of the heart chambers or heart valves

atrial septal defect

a hole in the wall between the right and left atria that allows mixing of oxygenated and deoxygenated blood