1
Q
What two things determine the flow of blood in vessels?
A
Pressure gradient
Resistance
2
Q
How is flow affected as branching occurs down the arterial tree?
A
Resistance increases so flow decreases
3
Q
What systems will aid venous return?
A
Valves in the veins
Respiratory movements
Movements of skeletal muscles surrounding veins acting as pump
Constriction of veins by sympathetic nervous system
4
Q
What is preload?
A
Venous return to the right ventricle
5
Q
What effect does the drug nitro-glycerine have on the heart?
A
Reduces preload
6
Q
How do nitrates work to reduce preload?
A
They cause vasodilation which reduces central venous pressure
