11/04 Flashcards by Rae Perry

What increases the probability of having circus movement?

slow conduction of the heart

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Circus movements predisposes us to

V-fib

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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

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Most common condition that can predispose the heart to a slow AP is

Hyperkalemia

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Major functions of the circularity system that is the kidney?

Transporting nutrients to tissues
Transporting waste products away from tissues
Transporting hormones: signaling

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Volume units?

some form of liter,
gallon

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velocity units?

distance/time
m/s
k/h

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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

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what unit of pressure do we use in the lungs?

cm/H20

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What is area in a&p?

size of the circle of a tube (vessel)
Could also refer to surface area

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units used to refer to blood flow

volume/time
mL/min
L/sec

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what is the most important factor that effects blood flow?

vascular resistance

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vascular resistance determines what kind of ______ we have

pressure

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If you measure the pressure between source of blood and resistance you would expect what kind of pressure?

high pressure

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If you measure the pressure downstream to the resistance in a vessel, you would expect what kind of pressure?

low pressure

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Pressure is used to drive ______

flow

i.e. brain uses CPP to drive brain blood flow

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Flow is altered or controlled by what the body is doing to _______

vascular resistance

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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

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Poiseuille’s Law measures ____ and takes into account other things like viscosity and/or density

Vascular resistance

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vast majority of blood is stored in

the rest of the blood is in the

systemic veins

higher pressure areas of the cardiovascular system

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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

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Why do the kidneys retain fluid?
vague answer

make up for some kind of deficit in blood volume

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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

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One tube connected to the end of another tube is called a system set up in _______

System in series

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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)

R_total=R₁+R₂+R₃ etc. R_total=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?

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