BLOOD FLOW

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(No Transcript)
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HEART PHYSIOLOGY

• (HOW THE HEART WORKS)

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HEART SOUNDS
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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
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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)
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ELECTROCARDIOGRAM(ECG or EKG)
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• Recorded electrical currents of heart
• Determine healthy heart

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

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BLOOD FLOW
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pulse

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

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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

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Blood pressure

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

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Cardiac output

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

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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

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• What does blood pressure measure?
• What factors can raise blood pressure?

Systolic Diastolic
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FACTORS AFFECTING BLOOD FLOW
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• 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

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HYPERTENSION
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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