Cardiac Definitions Flashcards
What is frank starlings law?
Higher the end diastolic vol (vol in each ventricle before it undergoes contraction) = harder contraction
Increase EDV Increase preload increase myocytes stretch increase contraction strength increase stroke vol increase cardiac output
What is starlings law on blood vessels (most relevant to capillaries)?
ONCOTIC PRESSURE = Force keeping blood in by albumin pressing on blood vessel walls
HYDROSTATIC PRESSURE = force squeezing fluid out by increase pressures of fluid
Stroke volume
The volume of blood ejected from each ventricle during systole
Cardiac output
The volume of blood each ventricle pumps as a function of time (liters per minute)
Total peripheral resistance
The total resistance to flow in systemic blood vessels from beginning of aorta to vena cava - arterioles provide the most resistance
Preload
the volume of blood in the left ventricle which stretches the cardiac myocytes before left ventricular contraction - how much blood is in the ventricles before it pumps (end-diastolic volume). When veins dilate it results in a decrease in preload (since by dilating veins the venous return decreases).
Afterload
the pressure the left ventricle must overcome to eject blood during contraction - dilate arteries = decrease in afterload
Contractility
Force of contraction and the change in fibre length - how hard the heart pumps. When muscle contracts myofibrils stay the same length but the sarcomere shortens - force of heart contraction that is independent of sarcomere length
Elasticity
Myocardial ability to recover normal shape after systolic stress
Diastolic dispensibility
The pressure required to fill the ventricle to the same diastolic volume
Compliance
How easily the heart chamber expands when filled with blood volume
