Module 3 Flashcards
Right Atrium
reservoir; receives low O2 blood from Vena Cava and coronary sinus
Ventricular Diastole
venous blood flows through tricuspid valve into right ventricle (80% of flow is passive)
Atrial Kick
contraction of atrium; responsible for 20% of blood flow to ventricle
Right Ventricle
pump contents through pulmonic valve into pulmonary artery; it is low in pressure compared to left, has thinner walls and a bellow-like contraction
Left Atrium
forms most of base of heart; receives O2 rich blood from pulmonary veins (4); blood flows through mitral valve to left ventricles; walls are slightly thicker than right
Interatrial septum
wall between right and left atria
Left Ventricles
pumping chamber; longer and thicker than right; has smooth outflow tract; has much more and thicker trabeculae than right; blood is pushed out of ventricle once enough pressure is generated to overcome resistance of semilunar valves
Systole
when the AV valves close and the semilunar valves open causing blood to be pumped into systemic circulation
Interventricular Septum
between the right and left ventricle; rigid just before contraction; serves as a fixed hinge
Inferior/Superior Vena Cava
a great vessel of the heart; empty low O2 blood from systemic circulation into right atrium
Pulmonary veins (4)
great vessel of the heart; 2 per lung; empty O2 rich blood into left atrium
Pulmonary artery
great vessel of heart; gets low O2 blood from right ventricle through pulmonic valve to lungs; branches into right and left pulmonary artery that connect for gas exchange at alveolar membrane
Aorta
great vessel of heart; O2 rich blood from left ventricle enters aorta through aortic valve; blood is sent to systemic circulation via brachiocephalic trunk, left common corotid artery, and subclavian artery
Tricuspid valve
AV valve; btw right atrium and right ventricle; prevents backflow of blood during ventricular systole; movement of valve is controlled by chordae tendinae (keep tension)
Mitral Valve
AV valve; 2 cusped valve between left atrium and left ventricle; prevents backflow during ventricular systole; chordae tendinae are thicker, stronger and more numerous than tricuspid
Pulmonic Valve
semilunar valve; 3 cusped valve btw right ventricular and pulmonary artery; prevents backflow into ventricle during right ventricular diastole; not supported by chordae tendinae or papillary muscles
Aortic Valve
semilunar valve; 3 cusped valve btw left ventricle and aorta; prevents backflow during left ventricular diastole; **coronary arteries originate above cusps of this valve at 3 sinuses; also not supported by chordae tendinae; secured by fibrous ring
Endocardium
inner most layer of chambers, valves, and vessels; smooth, single layer; functions to decrease RBC trauma and accumulation of platelets
Myocardium
middle layer of cardiac wall; the heart muscle- mechanical contraction; striated, involuntary; capable of fast electrical spread of excitation
Pericardium (epicardium)
outer most layer of cardiac wall; adheres to external wall of heart; composed of connective and adipose tissue; secures heart within thorax and allows passage of larger blood vessels and nerves that supply the heart
Pericardial Fluid
fills space between parietal and visceral layers of pericardium to minimize friction
Left coronary artery
passes between left atrium and pulmonary trunk and divides into LAD and LC
Left Anterior Descending Artery (LAD)
supplies anterior 2/3 of interventricular septum and anterior surface of left ventricle
Left Circumflex (LC)
supplies lateral and posterior walls of left ventricle
Right coronary artery
supplies right atrium and right ventricles; main branch is posterior descending coronary artery
Posterior Descending Coronary Artery
supplies inferior and posterior ventricles and posterior 1/3 of interventricular septum
Coronary artery disease
obstruction of blood flow to myocardium can cause damage to structures that coronary arteries supply
Coronary Sinus
coronary veins bring low O2 blood through myocardial capillaries to right atrium through the coronary sinus
Cardiac Output
volume of blood ejected from the left ventricle to aorta in 1 minute; CO= HR X SV
Stroke Volume
volume of blood ejected from ventricles per beat; determined by preload, afterload, and contractility
Preload
component of SV; association between the amount of myocardial stretching at the end of diastole (filling) and volume of blood ejected during next systolic contraction (the greater the distension in diastole, the greater the volume ejected in next systole)
Afterload
component of SV; resistance the ventricle must overcome during systole to propel blood into great vessels (resistance of aorta and pulmonic valve)
Myocardial Contracility
component of SV; changes in force generated by myocardium; determined by specific preload/afterload conditions
Heart Rate
determined by balance btw sympathetic and parasympathetic tone of NS (vagal tone)
Cardiac Index (CI)
used to compare CO amongst individuals since CO is dependent on body size; calculated by dividing CO by body surface area (BSA)
