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112 Cards in this Set
- Front
- Back
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Give me the route of the right heart
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Vena cava, atrium AV valve, ventricle, semilunar valve, pulmonary arteries
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Give me the route of the left heart
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pulmonary veins, atrium, av valve, ventricle, semilunar valve, aorta
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Myogenic
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self contracting
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How many chambers does the heart have?
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4
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How many directions can blood flow through a heart valve
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one
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Are cardiac muscle cells and pacemaker cells the same thing?
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No
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Blood comes back from the venus system through the
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vena cava
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From the vena cava ino the
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right atrium
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From the right atrium through the
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Right AV valve
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Right AV valve names
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tricuspid
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Through the tricuspid to the
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right ventrical
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From the right ventricle to the ____ through the ____
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lungs, Right pulmonary semilunar valve
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From the lungs back to the heart via the
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pulmonary veins
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From the pulmonary veins into the
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left atrium
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From the left atrium through the
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av valve
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Left av valve other names
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mitral valve, bicuspid
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Through the left av valve into the
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left ventricle
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From the left ventricle through the
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left semilunar valve
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Through the left semilunar valve and into the
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aorta
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Which heart is working more the left or right?
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Left
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How can you tell visibly that the left is working harder
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it has more muscle
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Why is the left heart working harder
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because its pumping blood through the entire body, righty is just going to the lungs.
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What valve opens first
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tricuspid
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What valve opens second
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pulmonary semilunar
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What valve opens third
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bicuspid
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What valve opens fourth
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aortic semilunar
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What allows for the blood to be pushed through valves
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pressure gradient
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When the left ventrical contracts, what contracts to close semilunar valve?
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Chordae tendinea and papillary muscles
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Difference between myogenic and neurogenic cells
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myogenic is in verts. Neuro is in inverts
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How does an action potential arise in pacemaker cells
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Permeability to sodium channels open. However important note: complete refractory period so that tetanus doesn’t occur |
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What are the 2 characteristics of cardiac muscle account for the plateau
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ap is caused by fast NA and slow Ca-Na channels. They open slow and stay open longer and cause the plateau. Plus calcium entering the cell enhance the contractile process. Immediately after onset of AP, permeability to K decreases by 5X, reducing outflux of K+ that is needed to return fibers to resting potential
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Syncytium
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the heart is made of many cells but functions as a hunit
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Heart cells are connected via
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gap junctions/electrical synapse
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2 types of heart cells
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autorhythmic and cardiac muscles
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What are the autorhythmic cells?
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SA node, AV node, purkinje fibers. They don’t contract.
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Where do cardiac and autorhythmic cells originate?
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Muscle blas cells
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What is distinctive about the action potential in pacemaker cells?
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Action potential ocilates
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What is different between heart cells and skeletal muscles in terms of DHPR?
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DHPR is not connected to the RyR.
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SERCA
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ATP bound pump which functions to pump calcium ions back into the sarcoplasmic reticulum
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HCN
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hyperpolarization activated cyclic nucleotide gated channel. The funny channel.
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What conducts the calcium current?
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Funny Current
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Chronotropes
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chemicals that change heart rate
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Neuropenephrine and epinephrine are examples of?
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Positive chronotropes
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Ach is an example of?
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Negative chronotropes
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Why is Ach inhibitory?
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Receptors in the heart are different than in the NMJ
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What causes muscle contraction?
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AP in muscle
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Why is the falling phase more prolonged in the cardiac muscles?
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Ca2+
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How much more prolonged is the cardiac muscle than the skeletal muscle?
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20-30X
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Sodium calcium exchanger
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Antiporter which removes calcium from the muscle cells to the extracellular fluid
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Calcium triggered calcium release
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calcium goes through channels to open the RyR to open the SR to release calcium
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Why regulate calcium?
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Heart can’t bulk up like a regular bicep muscle. So you can regulate the calcium. The more comes in, the more is removed.
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Event leading to Vth?
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Skeletal is through the AChR, but cardiac is through an electrical synapse. Pacemaker has a funny channel.
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Why is there no refractory period in a pacemaker cell?
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It’s continuously ocilating
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Skeletal cardiac and pacemaker: Difference in Vm
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S:-70mV stable C: -90mV stable P:-60mV Unstable
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Skeletal cardiac and pacemaker: Difference of rising phase of ap
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S: Na+ entry C: Na+ Entry P: Ca2+ Entry
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Skeletal cardiac and pacemaker: Difference in repolarization
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S: Rapid K+ Efflux C: Plateau due to Ca2+ entry, K+ efflux increases, Ca2+ decreases P: Rapid K+ efflux
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Skeletal cardiac and pacemaker: Difference in the Duration of AP
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S: Short 1-2ms C: extended 200+ms P: Variable (150+ms)
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Skeletal cardiac and pacemaker: Difference in refractory period
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S: Brief, just enough to reset the Na+Ch gates C: Long. resetting of Ca+ Ch delated until end of AP. P: None
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What generates the action potential?
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Atrium
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How does the heart pulse signal send?
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SA node passes it to the AV node. Atrium contracts. AV node to the bundle of his to perkinjie fibers. Ventricle contracts
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Why is there an AV node delay?
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The blood from the atrium should go through the ventrical, then from the ventrical out. If it happens simultaneously the blood wouldn’t move anywhere
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ECG
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Electrical view of the 3D heart, sum of total electrical activities
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3 major components of the ECG
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P wave QRS complex and T wave
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P wave
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atrial contraction
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QRS wave
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ventrical depolarization
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T wave
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Ventrical repolarization
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Where does the ECG start?
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Atrial depolarization
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Where does the ECG end
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just before the next atrial depolarization
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PR interval
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atrial contraction
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QT interval
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ventrical contraction
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Why is the QT interval longer than PR
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because of the AV delay
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Diastole
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relaxation/filling 70% of the cycle
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Systole
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contraction 30% of the cycle
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5 phases of the cycle
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mid/end diastole, atrial systole, isovolumic contraction, ventricular ejection, isovolumic relaxation
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What parts of the cardiac cycle are in systole? What parts in diastole?
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Systole is the isovolumic contraction and relaxation and the ventricular ejection. Diastole is the mid/end diastole and atrial systole
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Describe the pressure in the heart during late diastole
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Pvc>Pa>Pv
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Describe the pressure in the heart during Atrial systole
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Pa>>Pv (so the blood is forced into the ventricle)
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Describe the pressure in the heart during EDV
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Paorta>>Pv>Pa. Blood is not moving because the SL and AV are closed
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Describe the pressure in the heart during Ventricular ejection
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Pv>Paorta. Ventrical pressure exceeds arteries and SL valves open and blood is ejected
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Describe the pressure in the heart during Isovolumic ventricular relaxation
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Paorta>Pv>>Pa blood flows back into the cups of the semilunar valves and closes them. Blood may flow into the atrium
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Where is the Lub in the wiggers diagram and where is the dub?
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Lub is S1, Dub is S2
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Label this diagram:
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1: AV valves close. 2: Isovolumetric contraction. 3: SL valves open. 4: SL valves close. 5: Isovolumetric relaxation. 6: AV valves open. 7: Ventricular ejection. 8: Ventricular filling
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Draw a pressure volume loop of one cardiac cycle. Label it.
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EDV
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Preload, the amount of blood loaded before the heart ejects blood
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Is big or little EDV better for heart function?
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Big
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Factors affecting the work done by the heart
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EDV and afterload
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Cardiac output is impacted by?
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Heart rate and stroke volume
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EDV is affected by
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elasticity of ventricle wall, filling time, venous return, filling pressure, venous return
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ESV is affected by
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afterload and intropy
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What do ESV and EDV dictate?
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The work done by the heart
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If preload is high, stroke volume will?
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Increase
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If after load is high, stroke volume will?
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Decrease
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What determines how much blood goes into a ventricle?
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The more an artery contracts
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Good of ventrical compliance?
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More blood can get into the ventricle
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Venous compliance is bad because?
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More blood can get stuck int the venous system, then you can’t increase the pressure.
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The higher the heart beat
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the shorter the fill time, stroke volume decreases
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Venous return is reliant upon
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muscle contraction, respiration, gravity, vasoconstriction.
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Respiration and EDV
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Diaphragm constricts, relieving pressure around the heart, dropping ventricular pressure.
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Afterload
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resistance to ventricular ejection, the load that the heart must eject the blood against, aortic pressure.
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Starlings law of the heart
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as EDV increases pressure generated increases
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Positive intropes
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increase pressure without change in volume by increasing contractility
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Increaseing afterload on stroke volume?
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Decrease
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Decreasing intropy on stroke volume?
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Incrase
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Increase preload on stroke volume?
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Increase
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How is blood pressure monitored?
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Baroreceptors (aortic and carotid)
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If baroreceptors sense that your BP is too high
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vasodilation
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If baroreceptors sense that your BP is too low
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vasoconstriction
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Cardiac outputs most important function?
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Maintain MAP
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Cardiac function is to
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maintain blood pressure
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What affects TPR?
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Arterioles
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What affects arterioles?
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ANS (chronotropes and ionotropes) and hormones
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What affects heart rate?
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ANS (Chronotropes and ionotropes)
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