Cardiovascular Physiology

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Cardiovascular Physiology
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Blood flow and Pressure

• Cardiac cycle (pg. 357) repeated contraction and
  relaxation of the ventricles.
• 2 phases
• Systole heart contraction (120 mmHg)
• Diastole heart relaxation (80 mm Hg)
• 0.8 seconds
• Heart sounds

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Blood Flow Whats happening?

• R and L atria collect blood
• Pressure increases in atria
• Pressure is greater in atria than ventricles the
  AV valves open
• AV valves open
• 80 of blood flows from atria to ventricles.
  Atria contract releases remaining 20 of blood.
• Pressure in ventricles is above pressure in
  atria
• AV valves close
• High pressure in ventricles cause semi-lunar
  valves to open. Ventricles contract and blood is
  ejected (systole ideal pressure 120mmHg)
• Stroke volume amount of blood ejected from
  ventricles
• Increased pressure in aorta and pulmonary trunk
  causes semi-lunar valves to close
• All valves to ventricles are closed no blood
  exits/enters. Ventricles relax (diastole ideal
  pressure 80mmHg)

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Regulation of blood pressure

• Stroke volume amount of blood ejected from
  ventriclesmore blood higher pressure
• Cardiac rate increase heart rate increase of
  blood pressure
• Resistance how much resistance the heart meets
  when it pumps blood
• Baro-receptors feedback loop between brain,
  body, and blood vessels
• Renal factors the kidneys

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Baroreceptors

• Receptors found on the carotid arteries and
  ascending aorta ? brain ? blood vessels

vasodilation
vasoconstriction
Decrease pressure
Increase pressure
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Physical laws of blood flow

• Blood flows from one end of a blood vessel to
  another end by pressure gradient
• Factors that influence blood flow
• Diameter of blood vessel
• Vasoconstriction
• Vasodilation

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Vital signs measurements that provide an
indication of the efficiency of a persons
circulatory system

• Pulse pressure wave (70-76 beats per minute)
• Blood pressure pressure exerted on the inner
  walls of the blood vessels (120/80 mmHg)
• Body temperature
• Respiratory rate

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Homeostatic Imbalance of the circulatory system

• Varicose veins
• Pericarditis
• Valvular stenosis
• Myocardium infarction
• Murmurs
• Congestive heart failure
• Pulmonary edema
• Artherosclerosis
• Arteriasclerosis
• Congenital heart defects
• Coronary artery disease

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Special Circulations

• Arterial supply of the brain and the circle of
  Willis
• Hepatic portal circulation
• Fetal circulation

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