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
What does Interstitial Fluid Hydrostatic Pressure?
Pushing water in
If you have both hydrostatic pressures moving in the same direction, what does this mean?
Something is wrong
What is Net filtration?
It determines whether fluid moves into a capillary or moves out of a capillary
Net Filtration Pressure (NFP) is what equation?
Outward pressures added together - inward pressure added together = Net Filtration
If OUT - IN is NEGATIVE, it is called __________.
Reabsorption
The most important pressure is what?
Capillary Hydrostatic Pressure
Why is the Capillary Hydrostatic Pressure most important?
It is bigger than the other pressures and one most likely to change
If my arterial BP goes up, further down the line, what happens to my capillary hydrostatic pressure?
my capillary hydrostatic pressure up
For about the first 2/3rd of a capillary the outward pressures are more than the inward pressures. What does this mean?
It means that water is moving out of the capillary.
If water is moving out of the capillary, what happens to the capillary hydrostatic pressure?
Capillary hydrostatic pressure goes down because there is less blood in the capillary
What happens to capillary osmotic pressure when water is moving out of the capillary?
Osmotic pressure goes up because particles are NOT leaving, the water is. (Same # of particles but less and less water.)
When water leaves the capillary, where does it go?
Interstitial Fluid
As we move down the capillary and the water is leaving, what happens?
the capillary hydrostatic pressure is dropping and interstitial fluid osmotic pressure goes up.
As we move along the capillary, what happens to the outward and inner pressure?
The outward pressure gets smaller and the inward pressure are increasing.
At one point in this capillary, under normal circumstances, 2/3 to 3/4 of the way down, the inward pressures are going to become MORE than the outward pressures. What does it do?
To put water back in the capillary
At the beginning of a capillary, a healthy person in a resting situation, the capillary hydrostatic pressure is___________.
35 mm Hg
At the end of a capillary the capillary hyrdostatic pressure is__________.
18 mm Hg
Capillary Hydrostatic Pressure dropped in half. The only way to do that is when….
You want water to leave
The same # of particles in progressively less water, the concentration of particles has to go __________.
UP
When we have less and less water in the capillary, what happens?
The capillary hydrostatic pressure drops
When we have more and more water outside the capillary diluting the particles, what happens?
The Interstitial fluid osmotic pressure drops, capillary osmotic pressure goes up to suck water in, increase hydrostatic pressure to push more water in.
As we move down the capillary, there’s a point at which is equal. Before that, out pressure > inward pressure , what happens during this?
pulling water in the capillary
After that, the rest of the length of the capillary, inward pressure > outward pressure, what happens during this?
pulling water back in the capillary.
In a normal situation, in the last 1/3 or 1/4 of the capillary, you will reabsorb…
90% of water that get filtered in the first 3/4
If a person has hypertension and their capillary hydrostatic pressure starts with 50 mm Hg,
Even though fluid is moving, bc my capillary hydrostatic pressure is high coming into the capillary, instead of hitting balance point. Bc Out > In pressure for more of a length of a capillary, i’m filtering more water by far than reabsorbing. Blood volume goes down bc leaving water outside the blood vessel.
What does edema tell you in a patient?
It tells you that their outward pressure are high longer than they should be. Either something is wrong with their CHP or IFOP which causes fluid to move out.
If a patient is dehydrated, what does this tell us about the pressure?
COP is higher than it should be.
It means when i add my COP to my interstitial fluid, my outward pressure > inward pressure EARLIER in the length of the capillary. Steals water from interstitial fluid to increase blood volume.
What raises CHP?
it makes you filter more water out and lower blood volume
What lowers CHP?
move balance point to beginning point of the capillary and lets you pull in more water.
What lowers COP?
filter more
What is the main outward pressure?
Capillary Hydrostatic Pressure
What is my main inward pressure?
Capillary Osmotic Pressure.
What causes capillary osmotic pressure?
particles in the blood attracting water
What happens to a person with a low COP?
A person with liver failure and can’t make enough plasma proteins and can’t hold water in blood vessel and their blood volume drops.
What is pulmonary edema?
Water has left the pulmonary capillaries and is accumulating in the air sacs. CHP is too high or COP is too low.
At your capillaries_______________ move from the plasma into the interstitial fluid by filtration.
24 L of fluid
How many liters of those 24 L will be reabsorbed in the same capillary?
20.4 L
What is the goal of regulation for your cardiovascular system?
to maintain arterial blood pressure high enough to guarantee that all your parts are getting perfused (blood is getting delivered to them)
What helps us get blood to the areas of the body that need blood?
Local autoregualtion
What is Local autoregulation?
adjusting the resistance of arterioles in a particular area based on the chemical environment.
If O2 is low in a particular region, what does this cause?
Vasodilation of the arterioles
If I dilate blood vessels that lead to a place that needs more O2, what happens to the resistance?
there’s less resistance and more blood will go that way.
What causes vasodilation?
-O2 is low
-CO2 levels high
-Temperature being high
-pH being low
What causes vasoconstriction?
- O2 is high
-CO2 is low
What is Reactive Hyperemia?
reactive : (in response to ) hyperemia: (more blood than normal)
response to what that group of muscle is doing by sending them more blood to give them the energy and O2 to keep doing that
Neural control mechanisms. What are the arrow answers if there is HIGH BP?
⬆ BP> baroreceptor detects > CCC->CIC> ↓HR > ↓Q > ↓HR
baroreceptor ALSO detects > VMCC> vasodilate > ↓R > ↓BP
What does VMCC do?
(vasomotor control center) controls smooth muscle in the blood vessels.
controls if it vasodilate or vasoconstricts
Neural control mechanisms. What are the arrow answers if there is LOW BP?
↓BP> baroreceptor detects > CCC->CIC> ⬆️HR > ⬆️Q > ⬆️HR
baroreceptor ALSO detects > VMCC> vasoconstricts > ⬆️R > ⬆️BP
What is Autonomic tone?
Some level of sympathetic and parasympathetic activity all the time because it gives you the ability to increase or decrease both of them.
What is Vasomotor tone?
Always have at rest, some degree of vasoconstriction.
If arteries are partly contstricted, I have the ability to vasodilate. If they are fully relaxed, all I can do to raise my BP.
What makes ADH?
Hypothalamus
What releases ADH?
Posterior pituitary gland
Why would Posterior Pituitary gland release ADH?
Osmoreceptors in hypothalamus that monitor the osmotic concentration of body fluids. If osmotic concentration of body fluids gets high, it means either too many particles, or not enough water. ADH will be released and act on kidneys to make sure you retain more water.
What else does ADH do?
Vasoconstriction for an extended period of time
Where does Erythropoietin come from?
Liver
Where does the change of erythropoietinogen to erythropoietin occur?
Kidneys
What would be the stimulus to release more erythropoietin?
Low O2 in blood
Renin-Angiotensin Aldosterone System (RAAS)
is a vasoconstrictor that gears to increasing blood pressure.
When blood pressure detected by kidney baroreceptors are low, kidneys release a hormone called _____________ into the blood.
Renin
What does Renin do?
convert angiotensinogen to angiotensin I
The liver makes an inactive precursor called_____________ .
Angiotensinogen
What does Angiotensinogen do?
releases in the blood to be readily available.
Why is Angiotensin I made for?
a vasoconstrictor to be acted on again by a different enzyme to be converted into something else.
What does Angiotensin I become?
Angiotensin II
What does ACE inhibitor stand for?
Angiotensin converting enzyme
What is the job of ACE?
Converts Angiotensin I -> Angiotensin II
Where do we find ACE?
A membrane protein in endothelial cells of lung capillaries
Why is Angiotensin II the superhero of all hormones?
-increases contractility
-increases SV
-increases cardiac output
-increases erythropoietin conversion
-increases ADH release
-2 main stimuli for ADH release
-thirsty
What do we get from ADH?
water retention
what is the main stimulus for Aldosterone release?
Angiotensin II
What do you get from Aldosterone?
-increase Na+ retention
-increase K+ and H+ loss
What are three major components to act like blood when you bleed out?
-water
-sodium to retain the water
-RBC
What are the two different ways to get ADH release?
-you get dehydrated (increase osmotic concentration of body fluids that osmoreceptors in hypothalamus are looking at)
-have hemorrhage ( not gonna have an increase in osmotic pressure in my body fluids bc not only did I lose the fluid, the particles is lost too)
If you have less blood and no osmotic stimulus, how do you hold onto the water?
get ADH to go UP
How does Angiotensin II stimulate ADH release?
gives us a way to increase water retention even when we don’t have an osmotic stimulus
Where does Atrial Natriuretic Hormone come from?
The Heart
What causes Atrial Natriuretic Hormone to be released?
The atria being stretched more than they should
This long stretch causes what?
Cells in the wall of the atria to release ANH into the blood.
Atrial Natriuretic Hormone is BOTH what?
An antagonist and inhibitor of ADH and aldosterone
What does an inhibitor do?
block the release of something OR prevent it from binding to the receptor it needs to bind to , to do its job
What does an antagonist do?
What does Atrial Natriuretic Hormone do?
blocks the release of ADH, Aldosterone, Epinephrine, and Norepinephrine
What happens if you block the release of ADH?
lose water
What happens if you block the release of Aldosterone?
Lose more sodium
If you lose sodium, what happens?
No choice but to lose the water
If the effect of ADH, is water retention and Atrial Natriuretic Hormone makes you lose more water, what does this mean?
It makes it an antagonist of ADH
If the effect of Aldosterone is to increase sodium retention, and ANH causes you to lose more sodium, what does this mean?
It makes it an antagonist to Aldosterone
What else does ANH do?
increase water loss, increase sodium loss, and DECREASE in blood volume
If a patient has high blood pressure, what happens to RAAS?
If working right, High BP should decrease renin release, decrease angiotensin I which decrease Angiotensin II.
A change in blood pressure doesn’t have to be caused by a change in blood volume. ( vise versa) Why?
You can change the size of the pipes.
Can vasoconstrict and increase blood pressure without changing blood volume.
Can increase blood volume and not have BP go up bc you can vasodilate. (CANNOT ASSUME ONE CAUSE THE OTHER)
During light exercise, what happens?
local response where muscles uses O2 (O2 in tissue goes down, CO2 goes up, pH goes down, local vasodilators in the area cause vasodilation and more blood move into area to get more O2 there to clear out metabolic waste products
Use muscle in skeletal muscle pump to increase what?
Venous return (move blood back to heart, stretch RV, SV goes up in right side of heart, move blood from lungs into the left side of heart, SV goes up in left side of heart bc it gets stretched too)
When you heavy exercise gradually back to rest,
my respiration goes down, less respiratory pump, venous return start to drop, less stretch in RV, SV goes down, less blood gets into my LV, less stretch, SV goes down, CO goes down
Before your body picks up the idea that your blood volume and BP is dropping. What two things happen because of that?
Baroreceptor reflex to raise your blood pressure and arterial BP determines capillary hydrostatic pressure.
If my arterial BP goes down during hemorrhaging, what happens?
Capillary Hydrostatic Pressure goes down
What is a short term fix for BP?
fluid shift, baroreceptor reflex (increasing R & CO to raise BP)
What is the second wave effect on BP by
increase contractility, vasoconstriction, blood volume of ADH, Aldosterone, Erythropoietin
What are the two separate circulations?
Pulmonary circulation and Systemic Circulation
What is the Pulmonary Circulation pathway?
Right Ventricle and out to the lungs and back into the RA
What is the Systemic Circulation pathway?
LV out everywhere BUT the lungs, and back to RA
What are the areas of special circulations?
-Blood flow to the heart (myocardium)
-Blood flow to the brain
-Blood flow to the lungs
The first artery of the Systemic Circulation is ….
Aorta
What is the first branch off of the Aorta?
Brachiocephalic Artery OR Brachiocephalic Trunk
How many Brachiocephalic Artery do we have?
1
As you come off the Brachiocephalic Artery, the first branch coming off there is…
Right Common Carotid Artery
At the point where the right common carotid artery comes off, that’s the end of the brachiocephalic trunk and beginning of ….
Right subclavian artery
As you move along the subclavian artery, the next branch is smaller. This is…
Right Vertebral Artery
Why are the R & L Vertebral arteries important?
they guarantee blood flow to the brain
What does subclavian mean?
Under the clavicle
The subclavian artery changes into what?
Axillary Artery
What is the first thing that comes off the arch in the left side?
Left Common Carotid Artery
What does the Brachiocephalic trunk do?
The place of the beginning where blood supply to brain, head, and arms.
To take care of the right side of the head, right arm,.
Where is the beginning of the axillary artery?
The edge of the first rib
What does the axillary artery become?
It moves down the arm to become the brachial artery.
The brachial artery branches as we get along the elbow. Why does it branch?
So that you can flex your elbow and still have blood flow in your lower arm
What does the brachial artery branch into?
Ulnar artery and radial artery
What are the two arches found in the hands?
Palmar arches
What branches off the palmar arches?
Digital arteries
How many digital arteries are found in each finger?
2
What does the common carotid branch into?
external carotid artery (carries arterial blood for the outside of the head.)
What does the internal carotid do?
Supply blood to the brain
Where is the Carotid Sinus located?
between the internal and external
Where is the home of one set of your baroreceptors?
Carotid Sinus
What forms the basilar artery?
Two vertebral arteries
What absolutely guarantees the blood flow in the hypothalamus?
Circle of Willis (Cerebral Arterial Circle)
