Circulatory SYstem Flashcards
Flow of blood
arterioles through capillary beds and converge on venules
pre capillary sphincters open and close
to allow blood to pass through capillaries
When precapillary sphincter is open
capillaries are more perfused
When pre capillary sphincters are closed
there is little to no blood flow to capillary
veins are known as capacitence vessels, bc
they hold majority of bodys’ blood. approx 54 %
the smallest veins are called
venules
Weak valves in veins that allow blood to pool are referred to as
varicose veins
Varicose veins in the anal canal are
hemorrhoids
When blood travels through 1 network of capillary beds, that is
a simplest pathway
When blood passes through 2 consecutive capillary beds, it is a
portal system
When there is a convergence point between 2 vessels other than capillaries and can be considered the body’s natural shortcut, that is an
anastomosis
artery flows directly into vein, bypassing capillary
AV anastomosis
veins empties into another; most common anastomosis
venous anastomosis
when 2 arteries merge
arterial anastomosis
The force of blood pushing against blood vessel wall is the
blood pressure
Blood flow is proportional to pressure
EX: Flow increases, pressure increases
Blood flow is inversely proportional to resistance
Ex: Blood flow increase, resistance decreases
Arteries have a pulsatile flow, while
veoms have a steady flow
The difference between systolic and diastolic is the
pulse pressure
Factors that determine blood pressure
cardiac output, blood volume, resistance flow
Factors that affect resistance to flow.
viscosity, vessel length, and vessel radius
Blood volume is regulated by the
kidneys
The vessel radius adjusts by vasomotion, which is both
vasodilation and vasoconstriction
What allows vessel radius to experience vasomotion?
SMooth muscle in tunica media
Blood flow is proportional to _____ power of radius.
4th, r^4
These capillaries are found in organs where absorption and filtration is needed
Fenestrated capillaries
This capillary passes proteins, new blood cells, etc. These capillaries allow big things in & out
Sinusoidal “Discontinuous Caps”