mechanism of breathing

• What is the definition of external respiration?

  Ventilation or breathing
• What gases are exchanged during external respiration?

  Oxygen and Carbon Dioxide
• What is internal respiration?

  Exchange of gases between tissue and blood
• What is anaerobic glycolysis?

  Metabolism without oxygen
• What does Boyle's Law state about gas volume and pressure?

  If volume increases, pressure decreases
• What is the barometric pressure at sea level?

  760 mm Hg
• What is the intra-alveolar pressure at rest?

  760 mm Hg
• What is the intrapleural pressure at rest?

  758 mm Hg
• What is eupnoea?

  Normal, unlabored breathing
• What is the mechanism of inspiration?

  Active process involving muscle contraction
• How much does the diaphragm move during eupnoea?

  1.5 cm
• What is the role of external intercostal muscles during inspiration?

  Facilitate rib movement
• What happens to lung volume during expiration?

  Lung volume decreases
• What is the pressure in the lungs during expiration?

  761 mm Hg
• What muscles are involved in expiration?

  Anterior abdominal wall muscles
• What is the effect of the Valsalva maneuver on intrapulmonary pressure?

  Increases pressure by +100 mm Hg
• What is the physiological reason for negative intrapleural pressure?

  Balance between lung collapse and thoracic expansion
• What happens during deep inspiration to intrapleural pressure?

  Decreases to -30 mm Hg
• What is the clinical significance of emphysema?

  Loss of lung elasticity and decreased pressure
• What is the effect of gravity on intrapleural pressure?

  Varies from -7 at apex to -2 at base
• What is the formula for airflow in relation to pressure and resistance?

  F = (Pa - Pi) / R
• What factors primarily affect airway resistance?

  Radius of conducting airways
• What is the effect of parasympathetic stimulation on airway resistance?

  Constricts the airways
• What are the diseases associated with airway resistance?

  • Colds: Increased mucus production
  • Asthma: Constriction of small airways
  • Bronchitis: Thickened walls and excess mucus
  • Emphysema: Collapse of smaller airways
• What is the consequence of alveolar surface tension deficiency?

  Increased negative intrapleural pressure
• What are the key components of the mechanics of respiration?

  • Inspiration and expiration
  • Muscles involved in pulmonary pressure
  • Pressure changes during ventilation
  • Intrapleural and intrapulmonary pressure
  • Measurements and normal values
  • Applied aspects