FINAL EXAM - Lecture 1 Flashcards
Major functions of circulatory system include
Transporting nutrients to tissues, waste products away from tissues, and transporting hormones for signaling
Volume
L or mL
something with size
Velocity
Distance over time, or Meters/second
Pressure
how much force is needed, typically mmHG in the CV system.
Other organs systems
-lungs: cm/H2O
Area
Size that we have, may be cross-sectional (center of tube), or surface area (walls of the cylinder)
How we measure internal diameter?
Cross-sectional
How do we measure walls of a cylinder?
Surface area
Blood flow is given in
volume divided by time
ml/min, ml/sec, l/min
Vascular resistance is a big determination on what kind of ______ we have
Pressures and blood flow
i.e. Less resistance = greater blood flow
If we have an area in our artery that has an increased vascular resistance in one spot (chokepoint), is the pressure greater or lower distal to that high resistance area?
Lower
If we have an area in our artery that has an increased vascular resistance in one spot (chokepoint), is the pressure greater or lower proximal to that high resistance area?
Higher
Vascular resistance will dictate how much
pressure we have
How does brain control blood flow?
Increasing/decreasing vascular resistance
Inverse of vascular resistance?
Vascular conductance
Vascular conductance is
How easy it is to drive flow through a conduit (blood vessel)
If its easy to drive flow, it has a high conductance
If its hard to drive flow, it has a low conductance
Vast majority of our blood is stored in
systemic veins
If we took two individual tubes and stacked them end to end, and they each had their own resistance, this would be a
system in series
The resistance is added together.
if we took individual tubes that were parallel to eachother, and blood has an option to go between 4 tubes, this would be
System in parellel
Which system arrangement has a lower resistance?
System in parellel
Aorta has how much cross-sectional area?
2.5 cm2
Small arteries has a cross-sectional area of
20 cm2
Capillaries have how much cross-sectional area
2500cm2
Venae cavae has a cross-sectional area of
8cm2
As the blood gets further from the heart, the cross-sectional area cm2 of each section will ________. As it returns the to heart, the cross-sectional area cm2 will __________.
get larger; lessen
If we have a small cross-sectional area, blood flow will have a ________.
high velocity
As blood gets further from the heart, what happens to the velocity of the blood?
Low velocity
Left atrium has how much pressure?
Very low pressure
As we get further from the heart, what happens to the blood pressure?
decreases.
How does the pressure in the large arteries compare to the aorta? How do the small arteries compare to that? Arterioles? Capillaries?
Mostly the same, small arteries it starts to decrease.
Arterioles is when it really decreases, and then capillaries its the least.
Our high resistance blood vessels in systemic circulation are
Small arteries and arterioles
Chokepoint vessels in our bodies are
small arteries and arterioles
Veins in capillaries are ____ walled and _____.
thin;compliant
pressure gradient between capillaries and right atrium
only about 10mmHg
Kidney will manage blood flow by
adjusting vascular resistance
Can we have all of the blood vessels open all the time?
No, then there would be no pressure
Blood flow through the tissue will be dictated by the
metabolic rate
Laminar flow
Blood in the middle of the vessel will go the furthest
Blood closer to the walls of the tube wont make it as far, because the walls are the resistance.
The type of flow we would want to have everywhere and why?
Laminar flow. Its nice and orderly, its efficient, and it doesnt cause problems.
Turbulant flow is also called and what is it
disorderly flow. Its inefficient, and theres turbulance in the blood vessels. Blood flow can be fish hooked and moving not all in the same direction.
issues that turbulent flow can cause
deposit cholesterol and calcium into vessel walls
What can cause turbulent flow
Clot or blockage in the blood vessel. If there is a narrow opening for blood to go through, the blood will shoot through it very fast and when it gets to the other side of the obstruction, it sprays all over the place.
Think of putting your thumb over a garden hose.
What predicts the odds that turbulent flow will occur?
Reynolds equation
Kidneys get how much cardiac output per minute?
20% or 1L
Total cardiac output per minute
5L
Which organ gets more perfusion than it needs? why?
Kidneys. They need the blood flow to filter the blood.
How to measure blood flow?
Ultrasonic probe
Ohm’s law
V = IR but rewritten…
Voltage = current x resistance now becomes… Pressure, Blood flow, and vascular resistance (F = Delta pressure/ vascular resistance)
Delta pressure
difference of pressure between one end of the tube and the other
If there is a large delta pressure, we will expect
more flow
If there is a small delta pressure, we will expect
less flow
A very small change in blood vessel diameter, will
cause a huge change in blood flow
Vascular resistance is solved by? example?
using ohm’s law (R = delta pressure/flow)
In kidney, has 100mmHg of pressure in artery coming into kidney..
Coming out of kidney, renal vein has 0 blood pressure. (just easy number for example)
If kidney gets 20% of cardiac output, it gets 1000ml/min
Delta pressure = 100 - 0 mmHg
Flow = 1000ml/min
R= 100/1000 = 0.1
Renal vascular resistance = 0.1mmHg/ml/min
If conductance is the inverse of resistance, then
conductance = 1/Resistance
Capillary starling forces
important in determining whether fluid will move from inside of capillary to outside, or from outside to in.
Flow through a capillary pressure beginning and end
30 and 10
Delta P of capillary
20
