Overview of Circulation Flashcards
Systemic circulation feeds the
body
pulmonary circulation feeds the
lungs
what has the majority of the blood
veins & venules
left side pressure
high
right side pressure
low
pulmonary circulation pressures are much
lower
rate of blood flow to each tissue is almost always precisely controlled in relation to
tissue needs
if you’re exercising and some tissues needs more blood, what happens to rate of blood flow to that tissue
it will be met - it will get more blood if it needs more blood
cardiac output is controlled mainly by the sum of all
local blood flow
arterial pressure is controlled independently of:
local blood flow or cardiac output control
what determines blood flow through a vessel
ohms law
ohms law states that flow is dependent on
change in pressure over the resistance
ohms law equation:
Q = delta P/R
what does Q stand for in ohms law
flow
what does R stand for in ohms law
resistance
what does P stand for in ohms law
pressure difference
what equation governs flow throughout the body
ohms law: Q deltaP/R
most blood flows in the body by what type of flow
laminar flow
describe laminar flow
middle layer flowing faster than the outside ones
laminar flow, how does it sound
silent - you don’t hear it flowing in your arm, etc
describe turbulent flow
causes murmurs
how does turbulent flow sound
causes sound, sounds like a murmur
how does turbulent blood flow flow?
movement in opposite directions, the middle isn’t going faster than the rest like in laminar flow
two pressures that are the same on both sides of vessel, what happens to blood flow
it won’t flow
Flow =? (equation)
Flow = arterial - venous pressure/resistance
what is blood pressure
force exerted by the blood against any unit area of the vessel wall
what determines blood pressure
how much volume is in the vessel
where do we see the greatest drop in pressure
arterioles
why do we see greatest drop in pressure in arterioles
arterioles are resistance vessels of body - they can dilate or constrict
if arterioles constrict what happens to blood flow
less blood flows through them
arterioles help contribute to
blood pressure
if arterioles dilate what happens to blood flow
more blood flows through them
what happens to blood pressure if arterioles constrict
it increases
what happens to blood pressure of arterioles dilate
decreases
what is resistance
impediment to blood flow in a vessel
can resistance be directly measured
no
Resistance = ? (equation)
deltaP/Q
if you decrease resistance in organ, what happens to flow
increase
pressure gradient of 100 and decrease resistance what happens to flow
increase
increase resistance with pressure gradient of 100 what happens to flow
decrease
systemic side circulation, pressure is
high
why is systemic side circulation high
more resistance to blood flow
look at pg 12
12
in pulmonary hypertension, to get same amount of blood to flow through vessels what has to happen?
pressure has to increase
what is primary reason for resistance change
size or lumen of vessel
flow is proportional to the ___ power of the radius
4th
if diameter doubles, what happens to blood flow
see pg 13
review pg 13
13
what can change resistance besides pressure and radius
viscosity and length
what does poisuille’s law say
blood flow is affected by pressure differnece, radius, viscosity, length
what does l stand for in poiseuille’s law
length
longer vessel does what to resistance & flow
more resistance, less flow
increase in viscosity does what to flow
decreases
increase in viscosity does what to resistance
more
when would you get viscosity decrease in regards to blood
anemia
what happens to flow in anemia
increases
R total series =?
R1 + R2+ R3 + R4
how are our blood vessels arranged, series or parallele?
parallel
R = ? in parallel
1/Rtotal = 1/R1 + 1/R2 + 1/R3 + 1/R4
adding another vessel in parallel does what to total resistance
decreases
removing vessels does what to resistance in parallel
increase resistance
what is the ultimate purpose of the parallel in regards to flow ad our body
Permits each tissue to regulate its own blood flow independently of flow to other tissues
if blood flow to legs change will change to GI change?
no
what happens to venous return if more blood flow goes to legs (and GI flow doesn’t change)
goes up
when venous return increases what does it do
increase cardiac output - it will stretch heart which increases CO
more RBC will cause what to viscosity
increased viscosity
go through the questios he gave us
pg 18-21
