Ch. 17 (TEST #3) Flashcards
Is the pulmonary system high pressure?
NO
overall it is a lower pressure (less distance and allows more time for gas exchange)
Is the systemic system low pressure?
NO
it is under higher pressure (needs to be for the distance the blood has to travel)
What makes up the pulmonary system? (circulatory)
The right side of the heart and the pulmonary vessels
What makes up the systemic system? (circulatory)
Left side of the heart and the systemic vessels
Is the volume of blood pumped through each side of the heart different?
NO
They are actually the same volume, which is surprising considering what each side is pumping to
If a clot forms on the venous side of systemic circulation where will it most likely go?
Back to the heart and most likely will get lodged somewhere in the lungs
If a clot dislodges from the left side of our heart or our arterial systemic circulation what might happen?
It could get lodged somewhere in out systemic circulation.
Where do the coronary vessels branch from?
The AORTIC ARCH
Do the atrias have valves that prevent blood flow from the vena cava (right atrium) or the pulmonary vein (left atria)?
NO NO NO
Can the veins store some blood as a compensatory mechanism? What about the liver?
YES YES YES (but it can become s problem)
The liver can store up to 2L of blood if it needed to
How much of the blood volume do the arteries generally contain?
about 1/6 of TBV
venous side carries the majority
What happens if our blood volume gets too low?
Our vessels could collapse
What are two things that create a resistance to fluid flow?
Constricting arterioles
Increased hemotocrit
What are the two things that cause the pressure difference of our circulatory system?
The heart creating a pressure difference at the ends of the vessel (heart pushes blood through and creates the blood pressure to keep vessels open)
The vessels resistance to blood flow constricting arterioles and increased hematocrit increase this resistance)
Look at the slide she has that shows the pressure differences in each compartment of the heart… (about 13 minutes into her tegrity lecture is where you will find it)
SHE SAID WE DONT HAVE TO MEMORIZE THE NUMBERS, BUT IT IS A GREAT WAY TO UNDERSTAND THE CONCEPT OF DIFFERENCE IN PRESSURE IN THE HEART
DO IT NOW!
How does a higher pressure difference affect our flow rate?
it increases it
How does the blood flow between pressure differences?
It will travel from the area of higher pressure to the area of lower pressure.
What is the main difference in the anatomy between arteries and veins that give them their pressure differences (as well as their abilities to function under high pressure)? What about capillaries?
The arteries have a thicker muscular layer (tunica media) while the veins don’t
If the veins get under too high of pressure they will start becoming leaky (edema)
The capillaries have single layer walls that allow for the nutrient, oxygen, and fluid exchange
What cells make up the inner lining of all the blood vessels?
endothelial cells
creates a smooth surface and decreases resistance
What is laminar blood flow and where would it be the fastest? The slowest?
This is smooth regular blood flow
It will move the fastest in the center
It will move the slowest on the outside
What is turbulent blood flow?
This is interrupted forward current flow by crosswise flow
What are some things that can cause turbulent blood flow?
Branch points
obstructions
rough surfaces
increased velocity
decreased viscosity
What is one really bad thing that can happen with turbulent blood flow?
Platelets can get aggregated and form a clot
What do we look for when we are assessing for turbulent blood flow?
Murmurs (the heart)
Bruits
Thrills
Does our body sometimes create a purposeful turbulent flow?
YES
for instance, hemostasis
What does the law of LaPlace state?
The amount of tension generated in the wall of any vessel depends on the size (this includes the radius of the lumen as well as the thickness of the walls)
Dumb down the law of laplace.
Basically there is a pressure that is pushing out on the vessel walls that keep them from collapsing because of the tension that the vessel wall creates (which is dependent on the walls size and the radius)
WALL TENSION IS A PRODUCT OF THE ELASTICITY OF THE VESSEL (INTERNAL RADIUS)
What does the law of Poiseuille state?
Movement of blood through the vascular system is opposed by the force of resistance
In relation to poiseuilles law, what is the most important determinant of resistance?
What are a couple of other things that can increase resistance to flow?
CHANGE IN DIAMETER
increase in length and increase in viscosity are a couple other things
When you have an increased resistance to flow, what will have to happen?
You will need an increase in pressure
How do you calculate the flow rate of a vessel by its radius?
Take the radius to the 4th power
In relation to control of blood flow, how does the SNS (sympathetic nervous system) control it?
The SNS is the primary controller of blood flow
It mostly affects the arteries (because the veins have little innervation)
In relation to control of blood flow, how does the PSNS (parasympathetic nervous system control it?
It is an important regulator of our heart
NOT IMPORTANT TO REGULATION OF PERIPHERAL BLOOD FLOW
Name our great vessels.
Vena Cavae (inferior and superior vena cava)
Aorta
Pulmornary artery (deoxygenated)
Pulmonary vein (oxygenated)
What are the mechanical components of the heart?
The muscles of the heart and the valves
Name the layers of the heart (from the outside in) as well as their basic function.
Fibrous pericardium (tough outer layer, holds heart in position) Parietal pericardium (prevents friction)
PERICARDIUM ALSO STOPS HEART FROM BULGING TOO MUCH ON FILLING SO IT CAN BUILD A PRESSURE
Pericardial cavity (has a little bit of fluid to lubricate and prevent friction)
Visceral pericardium (prevents friction) myocardium (contractions) endocardium (smooth, prevents clots in heart)
Are you papillary muscles (connected to chordae tendinae) relaxed or contracted when the AV valves are open?
They are relaxed
So when the papillary muscles are contracted, the AV valves are closed, how can you make sense of this? (think about where the muscles are attached)
These muscles contracted along with the ventricular wall during systole, so it only makes sense that when the ventricles contract we want the AV valves closed so blood doesnt backflow.
What makes our semilunar valves open and shut?
Its all about the difference in pressure
When the pressure of the ventricles pushing on the valves exceeds the pressure on the other side of the valve (whether it be the systemic or the pulmonary circulation), it will open up, and it will closed based on the same priciple (pressure on other side of valve exceeds pressure exerted by ventricle)
Can the heart muscle generate its own action potential, is it the only muscle that can?
YES YES YES
YES YES YES
Describe the pathway of the impulses through the conduction system of the heart.
SA node
…impulse travels thorugh the intranodal pathways and bachmann bundle to the…
AV node
Bundle of his
Bundle branches (left and right)
Purkinje fibers (allow for rapid conduction of all ventricular muscles for almost synchronous contraction)
What is the primary pacemaker of the heart?
The SA node
It sets the rate (60-100)
If the SA node goes out and stops generating impulses, the AV node will take over (secondary pacemaker), what rate does the AV node set the heart to?
45-50 BPM
Describe a bundle branch block.
a delay in the bundle of his that slows transmission of impulse
Resting cardiac muscle cells have some of these channels open, what are they?
Calcium channels
The open calcium channels of resting cardiac muscle cells allow for what?
Ca2+ to leak into the cells making them more positive
What happens when enough CA2+ leaks into the cell for it to reach its threshold?
The NA+ channels will open and the cell will begin to fire
What Ion has a double + charge?
Calcium
What are the five phases of the action potential?
Phase 0 - As calcium slowly comes into the cells through the open channels it will hit threshold, causing the sodium channels to open and RAPID DEPOLARIZATION will occur
Phase 1 - There is an EARLY REPOLARIZATION where the sodium channels close
Phase 2 - Plateau,the slower calcium channels open allowing for calcium to exit the cell
Phase 3 - RAPID REPOLARIZATION, this is where calcium and sodium stops coming in potassium is pushed out
Phase 4 - RESTING MEMBRANE POTENITAL, the NA/K pumps transport NA out and K back in
Describe the absolute refractory period.
This is between phases 0-2 and early phase 3
Basically it is saying the in that time frame there cant be another stimulation (contraction) no matter how big of a stimulus, it has to go down below the threshold potential