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65 Cards in this Set
- Front
- Back
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blood leaving the RIGHT ventricle supply what circulation
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pulmonary circulation
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blood leaving the LEFT ventricle supply what circulation
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systemic circulation
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what are the SEVEN steps of the Contraction Process
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1. initiated by SPONTANEOUS AP in sinoatrial node
2. conducted through atria into ventricle. AP TRANSMISSION through atria into ventricle 3. DELAY 4. rapidly CONDUCTED through special fibers 5. ELECTROMECHANICAL COUPLING, calcium enters myocytes 6. CONTRACTION 7. EJECTION into large vessel |
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what is stroke volume
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blood volume ejection per contraction
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where is the greatest loss of pressure
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high resistance arterioles
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what is compliance
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the relationship between the amount of volume change to the amount of pressure change in closed system
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cardiac output
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volume pumped by heart per minute
CO=SVxHR |
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what is venous return and what is it numerically equal to
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the amount of blood pumped back into the right atria
equal to cardiac output |
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how is the CO an organ recieves related to its resistance
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INVERSE
organs with a higher resistance receive smaller % of CO organs are PARALLEL |
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what type of arrangement do vessels of the SAME type have within organs
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PARALLEL
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what arrangement do vessels groups of DIFFERENT types have within organs
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SERIES
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what is the composition of the walls of most blood vessels
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connective tissue (elastin and collagen)
vascular smooth muscle (VSM) |
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vascular smooth muscle is present in all vessel walls EXCEPT
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capillaries
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which vessel walls have the greatest percentage of vascular smooth muscle
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arterioles
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what happens when vascular smooth muscle CONTRACT? RELAX?
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contract: makes vessel stiffer
relax: makes vessels less stiff |
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what are general features of ELASTIC ARTERIES (conduit)
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aorta and lg branches conduct blood with little energy loss since they have low resistance to blood flow
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what are general features of MUSCULAR ARTERIES (distributing)
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conduct blood from larger arteries to and within organs
contribute to overall resistance in combination with arterioles |
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what are general features of ARTERIOLES (resistance vessel)
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regulate blood flow to capillary networks by changing their diameter, effects resistance to flow
high resistance is due to significant energy loss across arterioles |
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what is total peripheral resistance (TPR)?
what is the major determinant in TPR? |
totaly resistance to blood flow presented by the entire systemic vasculature
major determinant: ARTERIOLES |
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what are general features of PRECAPILLARY SPHINCTER (terminal arterioles)
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distal seg. of arterioles that guard entrance to capillaries
"fine-tuning" for localized capillary network pressure, flow and exchange area |
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what are general features of CAPILLARIES (exchange vessels)
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network of interconnected vessels 3-8 um in diameter comprising the blood-tissue exchange region
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what are general features of VENULES/VEINS (capacitance vessels and blood volume reservoir)
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thin walled
have vascular smooth muscle provide return pathway to heart store/metabolize blood vol. |
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what three components effect blood pressure
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cardiac pump
blood volume gravity |
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lowest pressure value?
highest pressure value? |
lowest: diastolic
highest: systolic |
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what is intravascular pressure
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total pressure inside vessels
cardiac pumping + blood vol. + gravity |
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perfusion pressure is equal to
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perfusion pressure=mean aortic pressure (MAP) - central venous pressure (CVP)
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in circulation where is the larger drop in blood pressure
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along the ARTERIOLES
high resistance |
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compared to the arterioles how is the change in the systemic venous pressure
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change in systemic venous pressure is much more GRADUAL than in the arterioles
much less resistance in systemic venous system |
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where is the lowest pressure in circulation
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near right atria
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what is the relationship between pressure difference, blood flow and resistance
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pressure difference= (blood flow)(resistance)
relationship not restricted to single blood vessels, can be applied at any two point in the body |
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describe vascular resistance
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blood moving through vessels
part of energy loss in form of heat due to friction balanced by an equal amount of energy supply in form of pressure |
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what formular is used to calculate total peripheral resistance (TPR)
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TPR= (MAP-CVP)/CO
TPR= perfusion pressure divided by cardiac output |
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the venous side holds what percentage of the systemic blood volume
blood volume in men? women? |
2/3
men: 6L women: 5L |
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what is the specific formula for resistance? general
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specific: R=(128/pi)(viscosity)(L/D^4)
general: R=perfusion pressure/blood flow |
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what is transmural pressure
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the difference between the extravascular pressure and intravascular pressure in blood vessels
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transmural pressure acts in what direction?
perfussion pressure acts in what direction? |
transmural pressure: radial
perfussion pressure: axial |
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what is the relationship between blood flow v.s. blood velocity
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Blood Velocity=(Flow)/(Area)
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what is shear stress
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the required force to move blood through vessels
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describe blood velocity along the circulation
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fastest coming out of the aorta
slowest through the capillaries because of the amount of cross sectional areas in the capillary beds and parallel arrangements. speeds up as its leaving the capillaries going into the venous system. |
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hematocrit
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volume concentration of red blood cells
viscosity increase directly but not linearly with increase in hemocrit |
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what is constant in a resistance SERIES? resistance PARALLEL?
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Series: FLOW constant
PARALLEL: PERFUSION PRESSURE constant |
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how to calculate Mid Capillary Pressure (Pc)
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1. subtracting pressure loss across Ra from Pa
2. adding Pv to pressure loss across Rv 3. Pc=Pv(Ra/Rt)+Pa(Rv/Rt) approximation: Pc~Pv+Pa(Rv/Ra) |
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compliance
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the ease with which a blood vessel can expand when transmural pressure is increased
C=(change vol.)/(change pressure) |
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elastic modulus
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a measure of how much force must be applied to increase the length of the wall material
greater the required force, greater the E |
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LaPlaces Law
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an equilibrium radius occurs if tension in a wall just balances effect of the distending tendencies of the transmural pressure
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what is the difference between tension and stress
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tension: force/length
stress: force/area |
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normal cardiac conduction pathway
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1. SA node spontaneously depolarize and act as normal pacemaker
2. Bachmanns Bundle: specialized inter-atrial tract; conduction pathway from RA to LA 3. Conduction pathway: SA to AV 4. AV node: slow and delayed, allows atria contraction to occur before ventricular contraction starts 5. Bundle of His: insert into interventricular septum, goto L/R bundle branches 6. Bundle Branches: travel down R/L branches, LEFT divides into 2 pathways 7. Purkinje Fibers: FAST, causes synchronous contraction throughout heart |
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what are the 5 phases of Fast Response Action Potential
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0. upstroke/rapid depolarization
1. early rapid repolarization 2. plateau* 3. repolarization 4. restin membrane potential *main characteristic of this phase |
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QRS complex
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reflects movement of the DW as it rapidly sweeps down the septum and depolarizes the ventricle apex, lateral wall and base
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what is the first measurable EKG?
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atrial deplorization, which causes the P-wave
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what is preload? what is it called in the heart
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in single muscle fiber, amount of stretch on the fiber as it starts to contract
at ventricle...end diastolic volume |
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Frank-Starling: law of the heart
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force and pressure developed by contraction depends directly on the PRELOAD
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contractility
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myocardial force-generating and length shortening potential at a given preload...INOTROPIC STATE
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intracellular calcium pool depends on what THREE aspects
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1. magnitude of I(ca)
2. relative duration of Ca++ influx (systole) and efflux (diastole) 3. extracellular [Ca++] |
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+ inotropic effects?
+ lusitropic effects? |
+ inotropic: effects describe increased force and rate
+ lusitropic effects: describes enhanced relaxation features of heart |
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effect on Vmax and shortening rate of afterload
increase in afterload causes... increase in contractility causes... |
increase afterload causes...DECREASE in SHORTENING RATE
increase contractility causes...Vmax and shortening rate INCREASES |
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best index for afterload is...
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stress in the LV wall that needs to be overcome by contracting muscle for muscle to shorten
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contractility as related to cardiac function curve
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increase in contractility shifts the CFC upward resulting in a greater SV for any preload
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cardiac cycle
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ventricle relaxed, chamber pressure low, matrial valve open, aortic valve closed.
1. filling rapid, then as pressure increases it slows down. 2. SA node fires, atrial kick 3. isovolumic contraction 4. ejection |
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when does isovolumic relaxation starts in the cardiac cycle
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when pressure in the relaxing ventricle falls below aortic pressure
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what is the best indicator of pump function
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ejection fraction: fraction of EDV ejected
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heart sound 1 is a result of...
heart sound 2 is a result of... |
S1: the onset of ventricular systole and the closing of the inlet valves
S2: the onset of diastole and the closing of the outlet valves. |
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stroke volume is equal to...
stroke work is equal to... |
stroke volume=width of the PV Loop=EDV-ESV
stroke work=area of PV loop approximated by the product of SV and MAP |
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what is pulse pressure
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the difference between the systolic and the diastolic
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name three ways systolic pressure and pulse pressure can increase
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increase rate of LV ejection
increase stroke volume decrease aortic compliance |
