Lecture 4: Cardiovascular Regulation Flashcards
Arterial Bp = CO x R means what?
Resistance and Arterial BP are directly proportional
If Resistance goes up, what goes up?
Pressure
What is Total Peripheral Resistance? (R)
ALL the resistance in ALL the blood vessels.
What kind of Resistance does it mean?
Resistance to the blood moving ; resistance to flow
When talking about the Total Peripheral Resistance, it is….
the total resistance to flow in the whole system
What contributes to the resistance to flow?
friction of blood rubbing up against blood vessel wall
What does friction depend on?
Vessel length and vessel diameter
The longer the vessel is, _____________________.
the more surface we have for blood to rub up against the wall.
With respect to the vessel diameter, what happens to the vessel?
the smaller the vessel is and more friction.
TRUE OR FALSE.
Can we change vessel length in a human?
FALSE
What is the main control for friction?
Changing the diameter of the blood vessel
The relationship between vessel length and resistance are______________.
Linear
If vessel length doubles, what happens to the resistance?
It doubles. ( Vis versa)
If we decrease the diameter of our blood vessel by half, resistance goes up by what?
16 times
Why is this important?
We don’t have to change the diameter of a blood vessel very much to change blood pressure.
At what level does our blood pressure regulation takes place?
Arterial
Why is it important that we do most of our adjustment at arteriolar level?
Because we have a huge # of arterioles and not many arteries
Higher viscosity of a fluid = what?
the more resistance to flow
What happens to a person with liver failure who doesn’t have enough plasma proteins being produced?
Plasma proteins help make the blood the right viscosity. And if we don’t have those, the blood gets thinner and makes less friction. This means less resistance and lower blood pressure.
A person has a hemorrhage and their body moves water around to defend their BP and hadn’t had time to make the RBCs that they lost. What happens to their blood?
Their blood gets thinner for a while and is harder to maintain their BP.
TRUE OR FALSE.
Do you need to change viscosity to adjust blood pressure?
FALSE
The thicker the line in a blood vessel means what?
the faster the blood is moving
What is the most efficient way for blood to move through a blood vessel?
Laminar Flow
What is Laminar flow?
(QUIET)
Blood next to the wall rubs on the wall most = moves the most slowly.
Blood in the middle doesn’t rub at all = moves the most quickly.
What is Turbulence?
( NOISY)
If there was a plaque formed, the layers that are hitting the plaque are getting bounced and disturb the other layers.
What is a total cross-sectional area?
Cut all elastic arteries of a person and measure the circle and add it all together
The biggest arteries have the lowest ____________.
cross sectional area
What is the highest cross sectional area?
Capillaries because we have billions of them
Blood pressure is highest where?
In the elastic arteries
Blood drops when?
It continuously moves through the body
The blood vessel with the biggest cross sectional area, have the most ____________.
slowly moving blood.
Blood in capillaries move slower in any other blood vessel. Why is this essential?
It gives you more time for exchange and diffusion
The slow speed of blood moving through capillaries lets what to occur?
Lets CO2 and O2 inside and outside the capillary to reach equilibrium.
Why is arterial BP important?
keeps blood moving through our capillaries
In the larger elastic arteries, is arterial BP constant?
NO, IT IS NOT
The highest BP in an artery?
Systolic pressure
In an elastic artery, what does the BP drops to when you’re NOT having ejection?
Diastolic Pressure
What is the difference between Systolic Pressure and Diastolic pressure.
Pulse Pressure
What is the Pulse Pressure equation?
Systolic Pressure - Diastolic Pressure = Pulse Pressure
What is the Dicrotic notch?
Proof of blood pressure tracing that aortic valve closes; causes a pressure wave.
What is mean arterial pressure ?
A weighted average of blood pressure
Why doesn’t BP drop to 0 during diastole?
It doesn’t drop to 0 because there is still fluid in the artery.
Normal arterial BP is what?
120 / 80 mm Hg
What do you call abnormally LOW BP?
Hypotension
What do you call abnormally HIGH BP?
Hypertension
In a normal situation, where a person is resting, the amount of blood leaving the heart should be___________.
equal to the amount of blood coming back from the heart.
The volume of blood coming back from the heart is called what?
Venous Return
Why are veins and pressure in veins are more affected by gravity?
Because the walls of veins are thinner and pressure are lower.
What is the Orthostatic effect?
Blood tends to want to stay in the legs bc gravity wants to pull down on it.
When a person that’s been sitting down stands up, what happens to their blood pressure and why?
Their BP drops because their body is not used to fighting gravity to get that blood back out of their legs.
What are the two names of drop of BP?
Postural Hypotension or Orthostatic Hypotension
What are the two mechanisms in the body that helps us move blood towards the heart?
Skeletal Muscle Pump and Respiratory Pump
What happens during the FIRST half of the skeletal muscle pump?
When the skeletal muscles contract, it puts pressure on the vein and makes the pressure gradient bigger and more blood will move up.
What happens during the SECOND half of the skeletal muscle pump?
What happens when you relax the muscle. When the muscle relaxes, the blood moves backwards and the valve closes.
Why does your legs become stiff when standing too long?
Blood is accumulating in your legs
What is the job of muscles?
Doing the work of making a bigger pressure gradient
What is the job of valves?
Doing the work of preventing blood from going back to where it started to progressively make progress
What is the respiratory pump?
When the diaphragm contracts, thoracic cavity gets bigger and abdominopelvic cavity gets smaller.
When you move the diaphragm down to breathe in, what happens to the pressure in the thoracic cavity?
the pressure in thoracic cavity drops.
When the diaphragm moves down, all the stuff that’s in the abdominopelvic cavity is in a smaller box. What happens to the pressure in the abdominopelvic cavity?
The pressure in the abdominopelvic cavity is higher
What runs through both of the thoracic cavity and the abdominopelvic cavity?
Inferior Vena Cava
What is the Pressure Gradient of thoracic part of IVC and abdominopelvic part of IVC?
At the inferior part of the IVC, there is more pressure on it bc pressure in the abdominopelvic cavity went up, it pushes more on the IVC, so the pressure in the IVC (abdominal part) goes up.
I lower pressure on the thoracic cavity, which means the pressure on the thoracic part of the IVC went down so the pressure in the IVC went down.
A Bigger pressure gradient means what?
More blood to move from the abdominal part of IVC to the thoracic part
When you breathe out, your diaphragm goes back where it was. (It relaxes) Since the thoracic cavity is smaller, what happens to the pressure?
The pressure went up bc diaphragm went up to where it should be and abdominopelvic cavity is bigger than IT WAS when taking a breath in. Pressure in the abdominopelvic cavity went down.
If Volume goes UP, what happens to pressure?
Pressure goes DOWN
If Volume goes DOWN, what happens to pressure?
Pressure goes UP
If blood flow towards the heart, what happens to the pressure?
the pressure ALWAYS has to be LOWER in the thoracic cavity than the abdominal cavity. Or else blood will flow in other way.
What are the two stage pumps?
Inspiration and Expiration
What is stage 1?
Inspiration : Move blood from the abdominal IVC to the thoracic IVC
What is stage 2?
Expiration: Moves blood from the legs (the abdominal IVC) and move blood from thoracic IVC into the heart.
When do you need these pumps?
During exercise
Why is does exercise change your breathing?
The harder you exercise, the more deeply you’re breathing. The further down your diaphragm moves, the bigger pressure difference from abdominal cavity and thoracic cavity.
What are the four pressures involved with moving fluid in the capillaries?
Capillary Hydrostatic Pressure, Capillary Osmotic Pressure, Interstitial fluid Hydrostatic Pressure, and Interstitial Fluid Osmotic Pressure
Capillary Hydrostatic Pressure
Blood pressure in the capillary
Capillary Osmotic Pressure
Osmotic concentration in the capillary
Interstitial Fluid is ________.
fluid that’s outside the blood vessels and between cells ; also pushes on wall of capillary
Interstitial Fluid Osmotic Pressure
the osmotic concentration in the fluid OUTSIDE the capillary
What are the two pressures to move fluid out of the capillary?
Capillary Hydrostatic Pressure and the Interstitial Fluid Osmotic Pressure
What does Capillary Hydrostatic Pressure do?
Pushes the water out
What does Interstitial Fluid Osmotic Pressure?
Pulls water out
What are the two Inward pressures?
Capillary Osmotic Pressure and Interstitial Fluid Hydrostatic Pressure
What does Capillary Osmotic Pressure do?
Sucks water in