Heart Valves <ul><li>Atrioventricular valves </li></ul><ul><ul><li>Tricuspid and Bicuspid </li></ul></ul><ul><ul><li>Preve...
Mechanisms to aid in return of blood to heart <ul><li>One way Valves </li></ul><ul><ul><li>Open to allow blood through the...
Problems with blood return <ul><li>Fainting </li></ul><ul><ul><li>Standing still too long without moving; particularly you...
Heart sounds <ul><li>Heart valves closing during each heartbeat create stereotypical sound “lub-dup” </li></ul><ul><li>“ L...
Heartbeat conduction <ul><li>Myogenic: </li></ul><ul><ul><li>The ability of the heart to contract is a property of the hea...
Heartbeat Diastole Diastole 0.40 Systole Diastole 0.30 Diastole Systole 0.15 Ventricles Atria Time (in seconds)
Conduction of heartbeat = 0.85 sec
Electrical and Contractile Sequence of the Heart Beat   <ul><li>SA node fires, initiating an impulse that rapidly travels ...
<ul><li>AV node transfers signal to rapid conduction pathway called the bundle of His  </li></ul><ul><li>Bundle branches d...
Extrinsic control of heartbeat <ul><li>Nervous Control of Heartbeat </li></ul><ul><ul><li>Cardiac center  in medulla oblon...
Hormones in heartbeat <ul><li>Chemical messengers (hormones) called catecholamines, which consist of adrenaline (epinephri...
Heart rate (72 beats/min) <ul><li>Factors: age, gender, exercise, body temp. </li></ul><ul><ul><li>fetus 140-160 beats per...
Blood Pressure <ul><li>The pressure the blood exerts against any unit area of the blood vessel walls </li></ul><ul><li>Sys...
Measured in the arteries
Sounds of Korotkoff <ul><li>Cuff tightens it cuts off the blood flow to your arm. As pressure is released, a thump is hear...
 
ECG (Electrocardiogram) <ul><li>Recording of electrical changes during a cardiac cycle </li></ul>
ECG   <ul><li>Normal heartbeat   </li></ul><ul><ul><li>Is the result of an electrical impulse  </li></ul></ul><ul><ul><li>...
 
ECG <ul><li>P wave-electrical activity initiated by SA node causing atria to contract </li></ul><ul><li>QRS wave-impulses ...
Arrhythmia (Irregular heart beat) <ul><li>Problems that affect the electrical system of the heart muscle  </li></ul><ul><l...
Irregular heart beats : Too slow <ul><li>Bradycardia  </li></ul><ul><ul><li>heart rate slower than 60 beats per minute </l...
Irregular heart beats : Too fast <ul><li>Tachycardia   </li></ul><ul><ul><li>abnormally fast heart rate, over 100 beats pe...
Heart Murmur <ul><li>Small deformity in valve – blood passes back into the atria after the valves have closed </li></ul><u...
Emergency Defibrillation <ul><li>Heart attack induces ventricular fibrillation </li></ul><ul><li>Regain normal rhythm </li...
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Lecture 3 summer 2004

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Lecture 3 summer 2004

  1. 1. Heart Valves <ul><li>Atrioventricular valves </li></ul><ul><ul><li>Tricuspid and Bicuspid </li></ul></ul><ul><ul><li>Prevent backflow into the atria when ventricles are contracting </li></ul></ul><ul><li>Semilunar valves </li></ul><ul><ul><li>Pulmonary and Aortic semilunar valves </li></ul></ul><ul><ul><li>Prevent backflow into the ventricles when they are relaxing </li></ul></ul>
  2. 2. Mechanisms to aid in return of blood to heart <ul><li>One way Valves </li></ul><ul><ul><li>Open to allow blood through then close to prevent backflow </li></ul></ul><ul><li>Skeletal muscle contractions </li></ul><ul><ul><li>Help to pump blood through by constricting veins and squeezing blood </li></ul></ul><ul><li>Breathing </li></ul><ul><ul><li>Help to pump blood through by constricting veins and squeezing blood </li></ul></ul>
  3. 3. Problems with blood return <ul><li>Fainting </li></ul><ul><ul><li>Standing still too long without moving; particularly your lower body </li></ul></ul><ul><ul><li>less blood circulating because of accumulation in veins; already have low blood pressure </li></ul></ul><ul><li>Varicose veins </li></ul><ul><ul><li>stretching of veins caused by accumulation of blood; </li></ul></ul><ul><ul><li>weak valves (allowed pooling of blood), standing too much </li></ul></ul><ul><li>Light headedness from lifting </li></ul><ul><ul><li>improper breathing </li></ul></ul>
  4. 4. Heart sounds <ul><li>Heart valves closing during each heartbeat create stereotypical sound “lub-dup” </li></ul><ul><li>“ LUB” = two atroventricular valves close during ventricular contraction </li></ul><ul><li>“ DUP” = two semilunar valves close during ventricular relaxation </li></ul>
  5. 5. Heartbeat conduction <ul><li>Myogenic: </li></ul><ul><ul><li>The ability of the heart to contract is a property of the heart muscle itself; it is not dependent on the body's nervous system </li></ul></ul><ul><li>But brain does control the rate </li></ul>
  6. 6. Heartbeat Diastole Diastole 0.40 Systole Diastole 0.30 Diastole Systole 0.15 Ventricles Atria Time (in seconds)
  7. 7. Conduction of heartbeat = 0.85 sec
  8. 8. Electrical and Contractile Sequence of the Heart Beat <ul><li>SA node fires, initiating an impulse that rapidly travels across the atria </li></ul><ul><li>Atria contract almost simultaneously (as a unit) forcing blood across the valves and into the ventricles </li></ul><ul><li>Signal passes on to the septum separating right and left halves of the heart : Atrioventricular node </li></ul><ul><li>AV node delays conduction of impulses from the atria to the ventricle (to ensure complete atrial contraction before ventricles begin contraction) </li></ul>
  9. 9. <ul><li>AV node transfers signal to rapid conduction pathway called the bundle of His </li></ul><ul><li>Bundle branches divide into right and left halves going to right and left ventricles respectively </li></ul><ul><li>Bundle of His accelerates the impulse and passes it down the interventricular septum to the Purkinje fibers </li></ul><ul><li>Purkinje fibers carry the impulse deep into the ventricular myocardial walls </li></ul><ul><li>Ventricles contract simultaneously (as a unit), forcing the AV valves shut, and pumping the blood into the aorta on the left and the pulmonary arteries on the right </li></ul>
  10. 10. Extrinsic control of heartbeat <ul><li>Nervous Control of Heartbeat </li></ul><ul><ul><li>Cardiac center in medulla oblongata can alter heartbeat through autonomic nervous system </li></ul></ul><ul><ul><li>Parasympathetic system promotes normal responses including slowing down heartbeat </li></ul></ul><ul><ul><li>Sympathetic system promotes stress responses including speeding up heartbeat </li></ul></ul><ul><ul><li>Need for oxygen, increase in blood pressure, etc. may activate systems </li></ul></ul>
  11. 11. Hormones in heartbeat <ul><li>Chemical messengers (hormones) called catecholamines, which consist of adrenaline (epinephrine) and noradrenaline (norepinephrine) help to speed up heart rate </li></ul><ul><li>Acetylcholine, has the opposite effect, causing the heart rate to slow </li></ul>
  12. 12. Heart rate (72 beats/min) <ul><li>Factors: age, gender, exercise, body temp. </li></ul><ul><ul><li>fetus 140-160 beats per min (FYI) </li></ul></ul><ul><ul><li>faster in women </li></ul></ul><ul><li>Exercise raises heart rate </li></ul><ul><ul><li>increases systemic blood pressure and routes more blood to the working muscles. </li></ul></ul><ul><ul><li>Trained athletes may be as low as 40-60 beats per min. </li></ul></ul>
  13. 13. Blood Pressure <ul><li>The pressure the blood exerts against any unit area of the blood vessel walls </li></ul><ul><li>Systolic (heart contracting) : Less than 120mm Hg </li></ul><ul><li>Diastolic (pressure at the moment your heart relaxes to permit blood flow into its chambers) : Less than 80mm Hg </li></ul><ul><li>Normal blood pressure written as 120/80mmHg </li></ul>
  14. 14. Measured in the arteries
  15. 15. Sounds of Korotkoff <ul><li>Cuff tightens it cuts off the blood flow to your arm. As pressure is released, a thump is heard (Systolic). This is what we hear as the “LUB” sound </li></ul><ul><li>As the cuff is loosened further, the pressure continues to fall and the lighter thumps are heard as the blood finds it easy to push pass the cuff. Thumping stops (Diastolic). This is what we hear as the “DUP” sound </li></ul>
  16. 17. ECG (Electrocardiogram) <ul><li>Recording of electrical changes during a cardiac cycle </li></ul>
  17. 18. ECG <ul><li>Normal heartbeat </li></ul><ul><ul><li>Is the result of an electrical impulse </li></ul></ul><ul><ul><li>Originates in a specialized area in the wall of the right atrium called the SinoAtrial node </li></ul></ul><ul><li>SinoAtrial node (a.k.a) SA node (a.k.a) Pace Maker </li></ul>
  18. 20. ECG <ul><li>P wave-electrical activity initiated by SA node causing atria to contract </li></ul><ul><li>QRS wave-impulses to stimulate ventricle to contract </li></ul><ul><li>T wave- electrical recovery of ventricles </li></ul>
  19. 21. Arrhythmia (Irregular heart beat) <ul><li>Problems that affect the electrical system of the heart muscle </li></ul><ul><li>Irregularities in initiation or conduction of impulses </li></ul><ul><li>Results in abnormal heart beat </li></ul><ul><li>Cause the heart to pump less effectively </li></ul><ul><li>Occurs due to </li></ul><ul><ul><li>coronary artery disease, high blood pressure, diabetes, smoking, excessive use of alcohol, drug abuse and stress </li></ul></ul>
  20. 22. Irregular heart beats : Too slow <ul><li>Bradycardia </li></ul><ul><ul><li>heart rate slower than 60 beats per minute </li></ul></ul><ul><li>Result </li></ul><ul><ul><li>low body temp, certain drugs, brain edema after head trauma </li></ul></ul><ul><li>In endurance type athletes, heart rate can lower and still provide the same cardiac output </li></ul>
  21. 23. Irregular heart beats : Too fast <ul><li>Tachycardia </li></ul><ul><ul><li>abnormally fast heart rate, over 100 beats per minute </li></ul></ul><ul><li>Due to </li></ul><ul><ul><li>stress, elevated body temp, stress, certain drugs or heart disease. Can promote fibrillation </li></ul></ul><ul><li>Rapid and irregular or out of phase contractions </li></ul><ul><li>Defibrillation - strong electrical shock </li></ul>
  22. 24. Heart Murmur <ul><li>Small deformity in valve – blood passes back into the atria after the valves have closed </li></ul><ul><li>Produces a swishing noise </li></ul><ul><li>Reduce efficiency of blood flow </li></ul><ul><li>Can hinder person’s ability to sustain normal activity levels </li></ul>
  23. 25. Emergency Defibrillation <ul><li>Heart attack induces ventricular fibrillation </li></ul><ul><li>Regain normal rhythm </li></ul><ul><li>CPR (Cardio-Pulmonary Resuscitation) </li></ul>
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