Mammalian Physiology--Z 315---Winter 1999

Study guide #3--Cardiac cycle

Cardiac Cycle

List the parts of the cardiac cycle and align with the EKG.

Know the status of the valves of the heart during each part of cycle and the EKG.

When are both valves shut?

What is a heart murmur?

What is the difference between stenosis and valvular insufficiency?

If the right AV valve was insufficient when would you hear a murmur?

If the right AV valve was stenotic when would you hear a murmur?

  • What would cause a diastolic murmur. During which part of th EKG would a diastolic murmur occur?
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    What is EDV? ESV? During which phase is it reached?

    What factors can change EDV? which will increase EDV which would decrease EDV?

    What factors can change ESV? which will increase ESV which would decrease ESV?

    What is the consequence of changing EDV or ESV?

     

    Cardiac performance

    What main two factors determine cardiac output?

    What factors can alter stroke volume?

  • Why is the Frank-Starling mechanism considered an intrinsic regulation of heart performance?

    Explain the physiological basis of the Frank-Starling mechanism?

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    What are the extinsic regulators of heart performance? Which factors do they alter?

    List three mechanisms by which sympathetic activity alters cardiac performance.

    What is contractility of the heart and how is it changed?

  • What is the basic mechanism by which parasympathetic activity alters cardiac performance?
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    Why would beta-blockers slow the heart rate?

    Which of the following conditions best represents the Frank-Starling mechanism at work
    which represent increased contractility?

    Condition X EDV= 150, SV=100 ml

    Condition Y EDV=120, SV= 70ml

    Condition Z EDV=120, SV= 85 ml

    What happens to CO as heart rate increases? What is the basis of this change?

     

     

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