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• Baroreceptors


  Receptors located in the vascular walls, especially of the aortic arch and carotid sinus area, that are sensitive to changes in arterial blood pressure
• Chemoreceptors


  Receptors that detect changes in chemical composition of the blood or tissues
• Baroreceptors


  • Stimulated whenever there is an increase in blood pressure
  • Cause slowing of the heart rate and increased force of ventricular contraction
  • Cause vasodilation
• The Valsalva Maneuver


  1. Subject takes a deep breath

  2. Subject expires forcefully with mouth closed

  3. Blood pressure and respiratory rate are taken
• The Valsalva maneuver is used as a test of the efficiency of the circulation in the face of decreased venous return
• During coughing or straining, the expiratory increased in intrathoracic pressure produces a marked rise in the pressure recorded from a peripheral artery
• The rise in intravascular pressure is exactly counter balanced by the rise in intra-thoracic and intra-abdominal pressures
• The differential of effective pressure in the aorta (the arterial pressure minus the intrapleural pressure) falls with a decrease in pulse pressure
• After release of the strain, there is an increase in both mean pressure and pulse pressure as the blood which has accumulated in extra-thoracic veins flood the heart
• The sinus and aortic nerves constitute a mechanism of utmost importance in controlling the arterial blood pressure and in maintaining the circulation to the brain
• The rise in diastolic pressure and increase heart rate which occur when the body changes from the recumbent to the sitting position or from the sitting to the standing position are apparently brought about through these nerves