Hemodynamics Flashcards
Veins
How do you determine the systemic pressure difference that drives blood flow (Q)?
Why is turbulent flow bad in the systemic vasculature?
- Can cause endothelial damage –> inflammation, dysfunction of endothelium (important for local vasodilation and autoregulation of CV system) –> can lead to atherosclerosis and / or thrombus formation
- Local pockets of static blood that’s not moving as much –> more likely to clot
In the CV system, what determines compliance?
- Changes in […] alter peripheral venous pressure
- How can venous pressure be altered?
- Nitroglycerin is a selective venodilator. What affect will this drug have on pre-load and oxygen demand?
- Blood volume
- Changes in venous tone via SNS activation
- It will vasodilate veins, increasing blood in veins, thereby decreasing blood that is returned to heart so decrease pre-load and decrease oxygen demand
Capillaries are arranged in parallel. This allows the body to alter local vasoconstriction and vasodilation to alter blood flow locally to tissues without changing total resistance. If total resistance is unchanged and flow is constant, then pressure will not change.
What must be the relationship between the pressure gradient and vascular resistance in order for blood flow to occur?
Pressure gradient must be high enough to overcome TPR
Normally the viscosity of blood does not change. However, there are circumstances that can change viscosity. When would this happen?
Polycythemia = genetic condition, too many RBCs
What 4 factors determine the resistance to blood flow?
- decreased
Capillaries