CARDIOVASCULAR SYSTEM

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CARDIOVASCULAR SYSTEM

• CHAPTER 15
• BLOOD PRESSURE

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BLOOD PRESSURE

• Definition
• Fluid pressure exerted on walls of vessels
• Usually arterial pressure
• Decreases as distance from heart decreases
• Fluctuations between ventricular contractions
• Systolic number top number
• Pressure as ventricles contract
• Arteries expand ? pulse
• Diastolic bottom number
• Resting pressure as ventricles relax
• Pulse pressure difference between systolic and
  diastolic pressures
• Directly related to cardiac cycle

DIAGRAM
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HOW TO TAKE C.A. 15.5 (598)

• Sphygomanometer
• Attach cuff to upper left arm
• Brachial artery
• Increase cuff pressure greater than arterial
  pressure
• Place stethoscope on antecubital
• No sound ? no blood flow
• Slowly decrease pressure
• 2-5 mmHg / sec for best results
• Korotkoffs Sound thump
• When you first hear sound Systolic
• When you stop hearing sound diastolic
• Normal values 120/80
• Younger people lower normal BP
• Hypertension abnormally high BP

PRESSURE IN VESSELS
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FACTORS AFFECTING PRESSURE

• Heart Action
• Stroke Volume amt. / heart beat
• Cardiac Output amt. / minute
• Stroke volume X heart rate
• Increase action increase BP
• Blood Volume
• More Blood higher BP
• Blood Viscosity
• Peripheral Resistance
• Vasoconstriction and vasodilation
• Disease
• Atherosclerosis fatty deposits (cholesterol)
• Arteriosclerosis hardening of arteries

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CONTROL AND PROBLEMS

• Starlings Law of Heart- greater the distention
  greater the force of contraction
• Keeps blood flowing
• Baroreceptors in carotid art. and aorta
• Cardiac center
• Parasympathetica and sympathetic NS
• Exercise, body temp, emotions
• Vasomotor reflexes
• Chemical influences
• CO2, H ions, O2

• Hypertension chronic high blood pressure
• Silent killer heart overgrowth
• Aneurysm
• Embolisms
• Stroke
• Kidney diseases
• Angiotensin II
• Alsosterone
• High sodium
• Obesity
• Stress
• Treatment
• Lifestyle and medications

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Blood Pressure and the Cardiac Cycle
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Pressure Vs Distance