A&P final Flashcards
What increases the probability of having circus movement?
slow conduction of the heart
Circus movements predisposes us to
V-fib
Which drug is fairly safe but can slow down the conduction system in the heart which makes it dangerous by predisposing the pt to V-fib
Lidocaine
Most common condition that can predispose the heart to a slow AP is
Hyperkalemia
Major functions of the circularity system that is the kidney?
- Transporting nutrients to tissues
- Transporting waste products away from tissues
- Transporting hormones: signaling
Volume units?
some form of liter,
gallon
velocity units?
distance/time
m/s
k/h
pressure is _____
Most of the pressure we are dealing with in the cardiovascular system is in this type of unit________
a force
mmHg
Pressure is how much force do I need to drive a column of mercury up by 1mm
what unit of pressure do we use in the lungs?
cm/H20
What is area in a&p?
size of the circle of a tube (vessel)
Could also refer to surface area
units used to refer to blood flow
volume/time
mL/min
L/sec
what is the most important factor that effects blood flow?
vascular resistance
vascular resistance determines what kind of ______ we have
pressure
If you measure the pressure between source of blood and resistance you would expect what kind of pressure?
high pressure
If you measure the pressure downstream to the resistance in a vessel, you would expect what kind of pressure?
low pressure
Pressure is used to drive ______
flow
i.e. brain uses CPP to drive brain blood flow
Flow is altered or controlled by what the body is doing to _______
vascular resistance
Vascular conductance is defined by
how easy it is to drive some kind of flow through some kind of conduit
ease-high conductance
difficult-low conductance
Poiseuille’s Law measures ____ and takes into account other things like viscosity and/or density
Vascular resistance
vast majority of blood is stored in
the rest of the blood is in the
systemic veins
higher pressure areas of the cardiovascular system
the kidneys are in control of how much fluid we have in our body which is tied to
how much blood that we have.
i.e. kidneys retain fluid or get rid of fluid which changes our blood volume
Why do the kidneys retain fluid?
vague answer
make up for some kind of deficit in blood volume
It’s okay to think of the kidney as a
big filter
It also is the control of the overall volume found in the cardiovascular system
One tube connected to the end of another tube is called a system set up in _______
System in series
Having multiple tubes for the blood to choose to flow through is called a system set up in _______
System in parallel
which gives a lower over all resistance:
Series or Parallel?
parallel system
What is the math to find the total resistance in a series
Formula for parallel total resistance? (said we didn’t have to know until spring)
Rtotal=R1+R2+R3 etc.
Rtotal=1/R1 +1/R2 etc.
What is the cross sectional area of a tube?
The diameter of the end of a tube
What is the cross sectional area of the aorta?
2.5cm2
What is the total cross-sectional area of the small arteries?
20cm2
It is so much higher than the aorta because there are a lot of them
What is the total cross sectional area of capillaries?
2500cm2
There are many many many capillaries in the body so total cross sectional area is much larger than the other types of vessels.
Total cross sectional area is reduced as we get ______ to the heart.
Why?
closer
There are >capillaries>veins>aorta.
Has to do with the quantity of that type of vessel.
If we have a lot of cross sectional area, the velocity of blood flow through any of those tubes is going to be
lower
There are so many of them that it has a ton of routes to choose from
If the cross sectional area is small, blood flow is going to have a ______ velocity
high
All of the blood has to go through this small cross section area
The left atrium has what kind of pressure?
low
The left ventricle pressure
high
BP _______as we get farther away from the________
decreases
heart
What are we seeing in this graph?
a product of the blood having reduced pressure as it flows through a conduit that has a high resistance.
What are our high resistance blood vessels in the systemic circulation?
small arteries and arterioles
phenylephrine effects on the arteriole side of things?
squeezes resistance arterioles and small arteries.
If you enhance the squeeze and then measure BP in the larger artery between the heart and the “choke point” you are going to have high pressure
If we look at the proximal side of the high resistance vessel (when giving phenylephrine) you would expect pressure to be _______
high
If we look at the distal side of the high resistance vessel (when giving phenylephrine) you would expect pressure to be _______
low
The main choke point or resistance vessels that determine what our BP is, are the:
small arteries and arterioles
Veins don’t have much_____
They are thin walled and compliant
resistance
What is the pressure gradient in veins between the end of the capillary and the right atrium?
10mmHg
The kidney manages the blood flow by adjusting:
vascular resistance
Why can’t we have all the pipes (blood vessels) open all the time?
We wouldn’t have any blood pressure
Blood flow through any tissue is typically dictated by ________
metabolic rate
High metabolic rate means you’ll need to increase _________
blood volume
The kidneys help manage this.
What is laminar flow?
A type of flow described as: nice orderly flow
-Very efficient blood flow.
-Blood closest to the wall of the tube doesn’t go as far. The walls are the resistance and the middle blood goes farther since it is farther away from resistance.
What type of blood flow do you want and why?
Laminar flow
It is efficient and doesn’t cause damage/problems
What is turbulent flow?
A type of flow described as: disorderly flow/turbulent flow of blood.
-Not efficient blood flow
-Blood goes in all different directions, looks like fishhooks, twists and turns
Turbulent flow causes what problems?
Remodeling of the vessels.
Things getting stuck that wouldn’t normally.
You could have Ca++ and cholesterol slammed into the vessel walls. The force of this causes them to stick in the sides of the walls
Like having your thumb over the end of the end of a garden hose, the blood coming out gets sprayed in every direction
what causes turbulent flow?
Having a clot in the vessel causing a narrow opening for blood to go through
Like having your thumb over the end of the end of a garden hose, the blood coming out gets sprayed in every direction
What does the Reynolds equation tell us?
The odds that turbulent flow is going to occur
Kidneys get what percent of minute cardiac output?
20%
1L/min
The kidneys are one of the few organs that gets much more______ than it actually needs. Why is this?
blood flow
They need the extra to be an efficient filter
Most tissues’ blood flow is determined by the metabolic demands of that tissue. Is this the case for the kidneys?
The kidneys are partially controlled by their metabolic requirements and part of the blood they get is extra so that they can be efficient filters.
How can you measure blood flow?
You can put an ultrasonic probe around the artery or blood vessel and look at things that way.
What formula should you use if you’re going to determine how much blood flows through a vessel?
Ohms law V=IR with some swapped variables
DELTA blood pressure=blood flow X vascular resistance
delta pressure is
differences in the pressures at the opposite ends of the tube
Ohm’s law rearranged to solve for flow
F= DELTA Pressure/Resistance
A very small change in blood vessel diameter can result in a very-
large impact on how much blood flows through that tube
constricting the vessel a little can reduce flow a lot
Ohm’s law rearranged to solve for resistance
R= DELTA P/ F
What are we saying is the blood pressure in the renal artery? (it is probably a little lower than this)
This is also about the pressure that would be in the
100mmHg
abdominal aorta
What are we saying is the blood pressure in the renal vein? (to make math easy?) (it is probably a little higher than this)
0mmHg
(probably really about 10mmHG)
Renal blood flow is about _____ of our cardiac output
20%
Conductance is the inverse of
resistance
We can think of the kidney in A&P as a
big ball of blood vessels that coordinate their actions to make the kidney a good filter
Capillary starling forces are very important in determining whether
Fluid will move from the inside of the capillary to the outside or if fluid outside the tube will move into the tube
(capillary hydrostatic pressure) Blood pressure at the beginning of a systemic capillary is almost always _______
Blood pressure at the end of a systemic capillary is almost always______
so delta P is ______
Delta P tells us what?
What do we have to take into consideration?
30mmHg
10mmHg
20mmHg
It is what drives flow through the tube from one end to the other
Whether the tube is permeable to fluid coming in or out.
How many capillary starling forces are there?
4
The inverse of vascular resistance is __________
vascular conductance
If you have a cardiac output of 5L/min, what would the blood flow be in the renal vein?
1L/min
or
1000mL/min
(20% of cardiac output)
Solve for resistance if your renal artery pressure is 100mmHg and your renal vein pressure is 0mmHg.
Renal Vascular resistance= 100mmHg-0mmHg/1000mL/min= 0.1mmHg/mL/min
How could you solve for resistance for the entire circulation ? (SVR)
SVR= aorta pressure - pressure in the right atrium / CO
