irregularly shaped, central area between the lungs in the thoracic cavity; contains heart, great vessels, thymus, trachea, & esophagus

the arteries, arterioles, capillaries, venules, and veins going to, within, and coming from the lungs

arteries, arterioles, capillaries, venules, and veins everywhere in the body except the lungs

temporary, small blood vessel in the fetal heart that connects the pulmonary trunk to the aorta; closes within 24 hrs after birth

layer of cells that lines the atria, ventricles, and valves of the heart

heart valve between the right atrium and right ventricle; has three leaflets or "cusps"

• small area of tissue between the right atrium and right ventricle
• is part of the conduction system of the heart, receiving electrical impulses from the SA node

• an impulse from the SA node changes the permeability of the myocardial cell membrane
• changes from the normally negative charge in a resting myocardial cell and causes a contraction of the heart

resting period between contractions of the heart

contraction of the atria or ventricles

constriction of smooth muscle in the wall of a blood vessel, causing it to become smaller in diameter

largest veins in the body (superior & inferior)

heart attack; death of myocardial tissue

a backward flowing; eg. the backflow of blood through a deficient heart valve

4 defects:

• ventricular septal defect
• narrowing of pulmonary trunk
• hypertrophy of right ventricle
• abnormal position of the aorta

abnormal heart sound created by turbulence as blood leaks thorugh a defective heart valve

• any type of irregularity in the rate or rhythm of the heart
• also known as a dysrrhythmia

arrhythmia in which there is a fast but regular rhythm (between 100 up to 200 beats/minute)