Blood Pressure

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Blood Pressure
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What is Blood Pressure?

• Blood Pressure is the force that blood exerts
  against the vessel walls.

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Blood Exerts Forces on Vessel Wall
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BP is the result of two forces

• The first force is when the heart pumps bloods
  into the arteries and through the circulatory
  system.
• The second is resistance to blood flow by the
  arteries as smooth muscles in their walls dilate
  (relax get larger) and constrict (contract get
  smaller)

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Vasoregulation

• The changing of the lumen (opening) size of a
  blood vessel regulated by smooth muscle in the
  walls

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Vasodilaton

• During Vasodilation, smooth muscle in blood
  vessel walls relax, reducing resistance to flow.
• Blood pressure is lowered.
• Vasodilation occurs near skin when it is hot to
  release heat and during exercise to allow blood
  to flow easier.

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Vasoconstriction

• During vasoconstriction, smooth muscles in blood
  vessel walls contract, increasing resistance to
  flow.
• Blood pressure increases.
• Vasconstriction in blood vessels. next to skin to
  conserve heat.
• Caffeine and Nicotene are powerful
  vasoconstrictors

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Cardiac Cycle

• The cardiac cycle has two phases, the heart is
  either working or resting.
• Systole the work phase where the heart muscle
  contracts
• Diastole the rest phase where the heart muscle
  relaxes
• The cardiac cycle alternates Systole, Diastole,
  Systole, Diastole

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Cardiac Cycle
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Systolic BP

• During systole, blood is forced into the arterial
  system, and the pressure rises.
• The peak pressure during systole is called the
  systolic blood pressure.

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Diastolic BP

• During diastole, the heart relaxes and the
  pressure falls.
• The pressure within your vessels during the
  diastole is called your diastolic BP.

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Blood Pressure Curve
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How is BP recorded?

• BP is recorded as a ratio.
• The systolic BP, or pressure during the work
  phase is recorded in the numerator. 110
• The diastolic BP is, or pressure during the rest
  phase is recorded in the denominator. 60
• Ex 110/60 mmHg

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How is BP measured?

• BP is measured with a sphygmomanometer (blood
  pressure cuff) and stethoscope.

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Normal BP Reponses to Exercise
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BP Responses to Breath-holding