Orthostatic Hypotension

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Orthostatic Hypotension

• Jessamy Toohey
• Jana Burkholder
• Kristen Parkin
• Rachael Williams
• Sonia Beljean

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Predictions

• What will change
• Stroke volume?
• Cardiac output?
• Arterial pressure in the foot?
• Capillary pressure in the foot?
• Heart rate?
• Total peripheral resistance?
• Venous pressure in the foot?
• Pressure in large cerebral arteries

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Pertinence to Class

• Bio 348/206 Discussed cardiovascular system
• Will be discussed next week in Lab and Lecture
• This is an introduction to concepts of blood
  pressure and peripheral resistance
• Also a review of reflex systems and homeostatic
  mechanisms

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Orthostatic Hypotension

• Orthosupright statikos to stand
• Hypotension low blood pressure
• Condition also known as postural hypotension.
• Orthostatic Hypotension is an abnormal decrease
  in blood pressure when a person stands up from a
  supine (laying down) position.

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Parameters defined

• Stroke Volume
• the amount of blood pumped by left ventricle
  during one contraction
• Heart Rate
• number of beats per minute
• Cardiac Output
• stroke volume X heart rate
• Total Peripheral Resistance
• resistance to blood flow created primarily by the
  arterioles

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Baroreceptor Reflex

• Baroreceptor stretch sensitive mechanoreceptors
  that respond to changes in pressure. Located in
  the carotid and aortic arteries.

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• When baroreceptors sense the decrease in blood
  pressure, they trigger a response via a
  homeostatic mechanism that increases heart rate
  and the force of contraction, causes
  vasoconstriction, which increases peripheral
  resistance and cardiac output, returning the
  blood pressure to normal.

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Analogy

• Water bottle on its side, all the water within
  it is evenly distributed.
• Stand the bottle up quickly and all the water
  rushes to the bottom of the bottle thus leaving
  no water at the top.
• Alka-Seltzer is dropped into the bottle. First
  the tablet will sink to the bottom, and as
  everything is activated, it starts to fizz and
  evenly distributes throughout the bottle.

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Questions?