Cardiac Output Flashcards
1
Q
Cardiac Output
definition
A
the volume of blood pumped by the heart every minute
stroke volume X heart rate
2
Q
Determinants of Stroke Volume
A
contractility (+)
preload (+)
afterload (-)
3
Q
Intrinsic Control of Stroke Volume
A
increased preload
- increases venous return/increases EDV
- this increases strength of cardiac contraction, leading to increased stroke volume
4
Q
Extrinsic Control of Stroke Volume
A
- increased sympathetic activity leads to contraction of venous system, increasing venous return
- epinephrine increases Ca 2+ influx, increasing contractility
5
Q
Compensatory Methods for Heart Failure
A
- increase sympathetic activity
- kidneys retain salt and water to increase blood volume
6
Q
Stroke Volume
definition
A
the amount of blood ejected by the ventricle in one beat
7
Q
Effect of Parasympathetic System
A
- no effect on ventricles
- negative inotropic effect on atria
- increases AV nodal delay
- decreases funny current
8
Q
Effect of Sympathetic System
A
- increases heart rate
- increases contractility
- opens more Na+ channels, increases funny current
