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HEART PHYSIOLOGY

(HOW THE HEART WORKS). HEART PHYSIOLOGY. HEART SOUNDS. HEART SOUNDS. Blood turbulence from closing valves 2 sounds: Lubb (closing of valves between atria and ventricles) Dupp (closing of valves after ventricles). HEART SOUNDS. Heart physiology.

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HEART PHYSIOLOGY

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  1. (HOW THE HEART WORKS) HEART PHYSIOLOGY

  2. HEART SOUNDS

  3. HEART SOUNDS • Blood turbulence from closing valves • 2 sounds: • Lubb (closing of valves between atria and ventricles) • Dupp (closing of valves after ventricles) HEART SOUNDS

  4. Heart physiology • Internal pacemaker regulates beating of heart by setting a rhythmic electrical excitation • Begins in (1) sinoatrial node (in right atrium) • to atrioventricular node (2)(between atria) to 3. bundle of His (3)to 4. right and left bundle branches (interventricular septum towards apex) (4) to 5. Purkinje fibers (from apex upward) (5) This “wave” of activity is picked up by an electrocardiogram (ECG)

  5. ELECTROCARDIOGRAM(ECG or EKG)

  6. Recorded electrical currents of heart • Determine healthy heart

  7. P wave: atrial depolarization (contraction follows) • QRS complex: ventricular depolarization • T wave: ventricular repolarization (start relaxing)

  8. BLOOD FLOW

  9. pulse • Alternating expansion and recoil of an artery • Wrist pulse = radial artery • Neck pulse = carotid artery

  10. Blood pressure • Generated by contraction of ventricles • Pressure exerted by blood on walls of a blood vessel • Highest in aorta; falls as distance from left ventricle increases • Bp, as a vital sign, measures pressure in aorta/large arteries

  11. Blood pressure • 2 measurements: systolic (heart contraction) and diastolic (relaxation) pressure. EX. 120/80 • Affected by cardiac output and peripheral resistance

  12. Cardiac output • Stroke volume x heart rate • Stroke volume (SV) = amount of blood ejected from heart each minute. • HR = # of beats per min.

  13. resistance • Affected by • diameter of blood vessel: • Blood viscosity (ratio of rbc to fluid): increase by dehydration, polycythemia; decrease to anemia, hemorrhage • Total blood vessel length: obesity

  14. What does blood pressure measure? • What factors can raise blood pressure? Systolic Diastolic

  15. FACTORS AFFECTING BLOOD FLOW

  16. Vol. of blood through any tissue for a given time period. • Factors: • Cardiac output: heart rate x stroke volume (amount of blood per minute) • Blood pressure • Resistance • Size of vessel diameter • Blood viscosity • Total blood vessel length

  17. HYPERTENSION

  18. High blood pressure • Major cause of heart failure and stroke • Causes: • Overweight • Excessive alcohol • Lack of exercise • Diet: • high saturated fat (meat/butter)*****, high salt, low minerals (potassium, calcium) • Stress ******** newest science indicates processed food is to blame, not saturated fat

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