Cardiovascular Anatomy

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Cardiovascular Anatomy
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Cardiovascular Anatomy

• Pulmonary circulation passes blood through the
  heart and lungs.
• Systemic circulation passes blood through the
  arteries, capillaries, and veins.
• Blood transfers gases, compounds, and heat.

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Cardiovascular Anatomy

• If legs are immobile, blood pools in them (venous
  pooling)
• Walking decreases ankle venous pressure.
• Walking aids blood circulation.
• Active standing is less uncomfortable than
  standing.

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Cardiac Output

• Output of left ventricle
• CO HR SV
• Basal cardiac output
• COBASL CI DBSA
• Activity cardiac output
• COACT CLMW TOTMET

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Blood Pressure

• The pressure blood puts on the blood vessel
  walls.
• Systolic pressure diastolic pressure pulse
  pressure.
• To estimate
• SBP 101.3 .68 AGE
• DBP 63.7 .36 AGE

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Metabolism

• Basal metabolism maintains body temperature,
  body functions, blood circulation.
• 1.28 W/kg for males
• 1.16 W/kg for females
• Activity metabolism provides energy for
  activities
• Very light work lt100 W/m2
• Light work 100 165 W/m2
• Moderate to heavy work 165 W/m2
• Digestion metabolism accounts for transformation
  of food

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Metabolism and Body Weight

• Basal metabolism body weight .86
• Activity metabolism hours body weight
  .86
• Digestion metabolism
• Daily calorie requirement
• Eating more or less results in weight gain or
  loss.

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Body Mass Index

• BMI (    Weight in Pounds             (Height
  in inches) x (Height in inches)) x 703

BMI
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Responses to Exercise

• Heart rate
• Stroke volume
• Arteryvein differential
• Blood distribution
• Going into debt

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Measuring Heart Rate

• Shining light on artery in earlobe
• Listening to sound through stethoscope
• Detecting surge of blood with fingers (palpation)
• Electronic recording and analysis

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Stroke Volume

• Amount of blood pumped through left ventricle
• Adjusts oxygen supply to the body
• Depends on exertion, body posture, exercise, and
  physical fitness
• Peaks at about 40 of maximum oxygen consumption

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ArteryVein Differential

• Difference between oxygen content of blood in
  arteries and blood in veins
• Increases in emergencies to up to 13 mL
• Normal coronary blood arteryvein differential is
  17 mL

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Blood Distribution

• During exercise, capillary density and muscle
  blood flow increase.
• Cramps may result from reduced digestion.

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Going into Debt

• Muscles draw on anaerobic oxygen stored in blood
• Anaerobic supply is limited and must be repaid

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Cardiovascular Limits

• Individuals work capacity is determined from
  maximum oxygen uptake (VO2max).
• VO2max is product of cardiac output and AV
  differential.
• Determined from treadmill or ergonometer test,
  step test, or walk/run test.
• Testing for screening purposes is controversial.

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Cardiovascular Limits

• What proportion of capacity is reasonable for
  work?
• Avoid anaerobic metabolism
• 50 for trained workers
• 33 for untrained workers
• Reduce for longer shifts.
• Mechanize high metabolic rate jobs.
• Reduce cardiovascular stress
• Engineering solutions (motors, wheels, balancers)
• Administrative solutions (job rotation, part-time
  work)

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Gender, Age, and Training Effects

• Average female VO2max 1530 lower than males.
• Industrial tasks should not require max output.
• VO2max decreases approx. 12/yr after age 25.
• Most of decline due to low physical activity and
  increased body fat, not age itself.
• Fitness can improve cardiovascular endurance,
  muscle strength, and flexibility.
• If work loads muscles dynamically, relax and
  stretch them.
• If work loads muscles statically, exercise should
  move them.

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Responses to Mental Work

• Mental load can be measured by heart rate
  variability.
• Low variability corresponds to high mental load.