a serious life threatening inflammation of the pericardium
pulmonary circuit
the blood vessels that carry blood to and from the lungs
systemic circuit
the blood vessels that carry blood to and from all body tissues
epicardium
also known as the visceral layer; external heart surface which is an integral part of the heart wall
myocardium
the middle layer of the heart; composed mainly of cardiac muscle; the layer that contracts
endocardium
the inner layer of the heart wall; white sheet of endothelium resting on a thin connective tissue layer
atria
superior heart chambers that receive blood
ventricles
inferior heart chambers that pump blood
auricles
small, wrinkled appendages located on top of atria which increase atrial volume a bit
fossa ovalis
a shallow depression in the interatrial septum where an opening called the foramen ovale existed in the fetal heart
fossa ovalis
depression marking the spot of the foramen ovale in the fetal heart
superior vena cava
returns blood from body regions superior to the diaphragm
inferior vena cava
returns blood from body regions below the diaphragm
coronary sinus
collects blood draining from thee myocardium
pulmonary veins
transports blood from lungs to heart
coronary circulation
the functional blood supply to the heart muscle itself
angina pectoris
thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium caused by vasospasm or stress induced from too much activity
myocardial infarction
prolonged coronary blockage leading to oxygen deficiency in affected area and cell death
stenosis
narrowing and stiffening of the valve
atrioventricular (AV) valve
prevent back-flow into the atria when the ventricles contract
tricuspid valve
right AV valve; has 3 flexible cusps
mitral valve
left AV valve with only 2 cusps; also known as bicuspid valve
papillary mucles
contract with other ventricular muscles to apply pressure to the chordae tendineae
chordae tendineae
tiny white collagen cords attached to each AV valve anchoring them to the papillary muscle
semilunar (SL) valves
aortic and pulmonary valves; guard the bases of the large arteries of the large arteries issuing from the ventricles; prevent back-flow into ventricles
sinoatrial (SA) node
generates impulses about 75 times/minute when person is resting; depolarizes faster than any other part of the myocardium; found in the right atrial wall
sinus rhythm
determines heart rate
atrioventricular (AV) node
smaller diameter fibers; fewer gap junctions so conducts impulses more slowly;
atrioventricular (AV) bundle
bundle of His; in the superior part of the interventricular septum; only electrical connection between atria and ventricles
right and left bundle branches
two pathways in the interventricular septum that carry the impulses toward the apex of the heart
purkinje fibers
complete pathway into the apex and ventricular walls
ectopic focus
abnormal pacemaker takes over
electrocardiogram (ECG or EKG)
a composite of all the action potentials generated by nodal and contractile cells at a given time
heart murmurs
abnormal heart sounds most often indicative of valve problems
cardiac cycle
all events associated with blood flow through the heart during one complete heart beat
systole
contraction
diastole
relaxation
heart rate (HR)
number of beats per minute
stroke volume (SV)
volume of blood pumped out by a ventricle with each heart beat
cardiac reserve
difference between resting and maximal cardiac output
preload
degree of stretch of cardiac muscle cells before they contract
contractility
contractile strength at a given muscle length, independent of muscle stretch and EDV
afterload
pressure that must be overcome for ventricles to eject blood, pressure in aorta and pulmonary trunk
hypocalcemia
not enough calcium; depresses heart
hypercalcemia
too much calcium; increases irritability of heart and may cause spastic contractions
hypokalemia
not enough potassium; arrhythmias and weak beats
hyperkalemia
too much potassium; lowers resting potential and can lead to block and arrest
tachycardia
abnormally fast heart rate, greater than 100 bpm
bradycardia
heart rate slower than 60 bpm
coronary atherosclerosis
poor blood flow to cardiac cells makes the heart weak and unable to contract
commotio cordis
mild blow to the chest cause heart to stop
cor pulmonale
right sided heart failure due to excessive pressure in the pulmonary circuit