Cardiovascular and Pulmonary Responses to Microgravity

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Cardiovascular and Pulmonary Responses to
Microgravity

• Wow, what a long title

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Overview

• Review Fluid Shift
• Cardiovascular and Pulmonary Physiology
• Responses to Space Flight

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If you can remember long ago

• Body fluids shift towards upper torso in
  microgravity
• Baroreceptors sense change in blood pressure
• Fluid unloading begins - astronauts lose lots of
  fluid volume

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Cardiopulmonary System
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Life of a Red Blood cell

• It takes 20 seconds for an RBC to make a full
  circuit of the body
• RBCs lifetime is about 4 months
• One RBC travels about 1500 km in that time

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Blood Pressure
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Stuff that Increases BP

• Blood Volume Increases
• Blood Viscosity Increases
• Stroke Volume Increases
• Peripheral Resistance Increases
• Heart Rate Increases

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Blood Components
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Consequences of Fluid Shift
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Heart Size in Microgravity
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Measuring Fluid Shift and Stuff
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Now Stand on Your Head!
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Countermeasures
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Review and Things to Remember

• Review Fluid Shift - why do astronauts pee so
  much?
• What happens to our hearts in microgravity?
• What happens to our blood content in
  microgravity?
• What things can change blood pressure?

• Cardiopulmonary system takes oxygen to the body
  tissue
• Increased activity increases stress on the
  cardiovascular system
• Changes in environment can affect the way our
  bodies work huh?

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Questions?