Cardiac Part 2 Flashcards
(81 cards)
What is the precordium?
Area on anterior chest overlying heart and great vessels
How many chambers does the heart have?
Four chambers: atria and ventricles
What are the two major blood circulation loops?
- Pulmonary circulation
- Systemic circulation
What is the pericardium?
Tough, fibrous, double-walled sac that surrounds and protects heart
Define myocardium.
Muscular wall of heart
What is the endocardium?
Thin layer of endothelial tissue that lines inner surface of heart chambers and valves
What are the two pump systems in the heart?
Each side of the heart has an atrium and a ventricle
What is the main purpose of heart valves?
Prevent backflow of blood
How do heart valves operate?
Open and close passively in response to pressure gradients in moving blood
Name the types of valves in the heart.
- Two atrioventricular (AV) valves
- Two semilunar (SL) valves
What is the function of the tricuspid valve?
Right AV valve
What is the function of the bicuspid or mitral valve?
Left AV valve
What occurs during diastole?
Ventricles relax and fill with blood; 2/3 of cardiac cycle
What happens during systole?
Heart’s contraction, blood pumped from ventricles fills pulmonary and systemic arteries; 1/3 of cardiac cycle
What is isometric contraction?
Contraction against closed system that builds high level pressure in ventricles
What does S1 signify?
Closure of AV valves; signals beginning of systole
What does S2 signify?
Closure of semilunar valves; signals end of systole
True or False: The volume of right and left ventricular systole is always equal.
True, but can be affected by respiration
What is the third heart sound (S3) associated with?
Occurs when ventricles resistant to filling during early rapid filling phase (protodiastole)
What does the fourth heart sound (S4) indicate?
Occurs at end of diastole when ventricle resistant to filling
What are heart murmurs caused by?
- Increased blood velocity
- Decreased blood viscosity
- Structural defects in valves
What is cardiac output?
Volume of blood pumped by heart per minute; CO = HR x SV
Define preload.
Venous return that builds during diastole
What is afterload?
Opposing pressure ventricle must generate to open aortic valve against higher aortic pressure