Vascular Control I Flashcards
Input=
Venous return
The heart is a _____________ that acts upon an _____________ in order to produce an __________________.
Dynamic system
Input
Output
Output=
Cardiac output
If there are changes in a hearts input, are changes in output required?
Yes, the body does everything it can to keep these equal to one another
What is preload?
End diastolic volume
What is afterload?
End systolic pressure
What happens when preload increases?
Stroke volume and cardiac output also increase
Is preload or after load a reflection of volume status?
Preload
Where does the majority of the volume reside in the circulatory system?
In the peripheral venous compartment
Which vascular compartment is associated with preload?
Central venous compartment
What vascular compartment is associated with after load?
Arterioles
Blood leaves the central ventouse compartment (right atrium) by entering the right ventricle at a rate that is equal to…..
Cardiac output
What is the definition of venous return?
The rate at which blood returns to the thorax from the peripheral vascular beds (the rate it enters the central venous compartment)
What anatomical structures comprise the central venous compartment?
Great veins in thorax and right atrium
Which pressure is larger, peripheral venous pressure, or central venous pressure?
Peripheral venous pressure
What happens when peripheral venous pressure is EQUAL to central venous pressure?
There is no flow
When blood volume or venous return increases, what happens to the venous function curve?
It shifts to the right
What happens to the RAP at any constant CVP with an increase in pump flow?
It decreases
at increase pump rates, the amount of blood in the arterial system _______________ while the amount of blood in the venous system _______________. What is the effect on the pressure for each?
Increases
Decreases
The arterial pressure increases and the venous pressure decreases
What is MSFP?
Mean systemic filling pressure. It is the bold pressure at zero flow.
Does MSFP increase or decrease with greater blood volume?
It increases
At any given RAP, an increase in CVP with increased blood volume drives greater venous return. What is the effect on the vascular function curve?
A shift upwards
Do vasoconstriction and vasodilation effect MSFP?
No, because blood volume has not changed (you are just shifting where it is)
When arterioles vasodilate, what is the effect on stroke volumes and cardiac output?
Stroke volume increases, cardiac output increases
A transient increase in RAP, there would be an _____________ in CO and a _____________ in VR (venous return).
Increase
Decrease
What are the effects of a transfusion on MAP and CO?
There is an increase in both
What is the way to produce a different steady state match between venous return and CO?
Change BOTH the cardiac function curve and the vascular function curve
