Lecture 1 8/21/24 Flashcards
What is the basic function of the CV system?
pump blood in order to meet metabolic needs while maintaining adequate perfusion pressure and low filling pressures
How does the cardiac output of the left and right heart compare over time?
they are equal over time
How do systemic and pulmonary circulation differ in terms of O2 and pressure?
-systemic circ. has high O2, high pressure
-pulmonary circ. has low O2, low pressure
How does the geometry of the ventricles differ?
-right vent. has pyramidal geometry
-left vent. has cylindrical geometry
What is resistance?
measure of opposition to electrical current
What is the equation for BP?
BP = CO x VR
How does vessel radius impact resistance and pressure?
increased radius leads to decreased resistance and less pressure needed for flow
What is stroke volume?
volume of blood that the heart ejects each systole
What is cardiac output?
volume of blood pumped by the heart in one minute
What are the determinants of cardiac output?
-heart rate
-preload
-afterload
-contractility
What is preload?
force that stretches the myocardium prior to contraction
What is the relation between heart rate and cardiac output?
direct
What is the relationship between cardiac output and preload?
direct
What is afterload?
force that opposes ventricular ejection
What is the relationship between cardiac output and afterload?
inverse
What is the relationship between contractility and cardiac output?
direct
What is contractility?
strength of the myocardium
What is heart failure?
-impaired emptying or filling of the heart
-leads to clinical signs of exercise intolerance and/or congestion
How does heart failure differ from heart disease?
heart failure is a syndrome that can result from any heart disease
What is Stage A heart failure?
predisposed to the development of heart failure
What is Stage B1/B2 heart failure?
-subclinical structural heart disease
-chamber enlargement in B2 stage
What is Stage C heart failure?
-structural heart disease
-current or prior clinical signs
What is Stage D heart failure?
refractory heart failure
What are the possible anatomical classifications of heart failure?
-pericardial
-myocardial
-endocardial/valvular
-conduction system
What are the potential pathophysiologic mechanisms of heart failure?
-volume overload
-pressure overload
-contractile dysfunction
-diastolic dysfunction
-arrhythmias
-high cardiac output states
What are the characteristics of eccentric hypertrophy?
-response to volume overload
-in-series replication of sarcomeres
-hypertrophy and dilation
-increased diastolic volume
-preserved ratio of wall thickness to lumen
What are the characteristics of concentric hypertrophy?
-response to pressure overload
-parallel replication of sarcomeres
-hypertrophy without dilation
-normal diastolic volume
-increased ratio of wall thickness to lumen
