Week 11 - Resp Phys master

• What is respiration?

  It is the exchange of gases between the atmosphere, blood, and cells
• What three processes are required for respiration to occur?

  • Ventilation (breathing)
  • External (pulmonary) respiration
  • Internal (tissue) respiration
• What is the average volume of air breathed per breath at rest?

  500 ml
• How many times does a normal human breathe at rest?

  12 to 15 times a minute
• How much air is inspired and expired per minute at rest?

  6 to 8 litres per minute
• What happens to oxygen and carbon dioxide during gas exchange in the lungs?

  Oxygen enters the blood in the pulmonary capillaries while carbon dioxide enters the alveoli
• What are the structural divisions of the respiratory system?

  • Upper respiratory system: nose, pharynx, larynx, and associated structures
  • Lower respiratory system: trachea, bronchi, and lungs
• What are the functional divisions of the respiratory system?

  • Conducting zone
  • Respiratory zone
• What is anatomical dead space?

  It refers to the part of the airway not involved in gas exchange, averaging 150 ml
• How is the volume of fresh gas calculated during ventilation?

  Volume = 500 ml inhaled - (500 ml - 150 ml) x 15 breaths/min = 5,250 ml/min
• What is alveolar dead space?

  It refers to alveoli that are ventilated but not perfused
• What are the functions of the conducting zone?

  • Transports air to the lungs
  • Warms, humidifies, filters, and cleans the air
  • Voice production in the larynx
• What structures make up the upper airway?

  Nose, pharynx, larynx, and associated structures
• What structures make up the lower airway?

  Trachea and bronchial structures to the alveolus
• How do the main-stem bronchi branch?

  They branch into lobar bronchi and then into segmental bronchi
• What is the significance of the carina in the trachea?

  It is the point where the trachea divides into the right and left main-stem bronchi
• Why is nasal breathing preferred?

  It filters particulate matter and humidifies inspired air
• What is the role of the diaphragm in respiration?

  It is the most important muscle of inspiration
• What happens to breathing during exercise?

  Switch to mouth breathing due to higher resistance in the nose
• What is Boyle's Law?

  The volume of a gas varies inversely with its pressure
• How does Boyle's Law apply to the lungs during inhalation?

  When the volume of the thorax increases, the pressure in the lungs decreases, allowing air to flow in
• What is the primary principle of ventilation?

  Air moves down its pressure gradient from high pressure to low pressure
• What is Fick's Law in relation to gas exchange?

  It states that the blood gas barrier is extremely thin and has a large surface area
• What is transpulmonary pressure?

  It is the pressure difference across the lungs
• How does fluid in the lungs affect diffusion distance?

  It increases the distance of diffusion
• What factors can reduce lung compliance?

  Conditions that make lung tissue stiffer, such as pulmonary fibrosis
• What is lung compliance?

  It is the ease with which the lungs and thoracic wall can be expanded
• What disorders can affect lung elasticity?

  Disorders such as emphysema can affect ventilation
• What is the role of elasticity in the lungs?

  It allows the lungs to stretch on inhalation and recoil during exhalation
• What is the structure of a normal alveolus?

  • Type I cells line most of the alveolar surface
  • Type II cells occupy about 7% of the alveolar surface
  • Capillaries surround the alveoli
• What is the diffusion pathway for oxygen and carbon dioxide in the pulmonary capillary?

  It consists of the alveolar–capillary barrier, plasma, and erythrocyte
• What is the primary function of the respiratory system?

  Gas exchange
• What are the two types of cells that line the alveolar surface?

  Type I and type II cells
• What is the role of type I cells in the alveoli?

  They facilitate optimal gas diffusion
• What is the function of type II cells in the alveoli?

  They produce surfactant, decreasing surface tension
• What is the structure that separates the alveoli from the pulmonary capillaries?

  The alveolar–capillary barrier
• What is the significance of the pulmonary circulation?

  It brings deoxygenated blood from the right ventricle to the gas-exchanging units
• What is the bronchial circulation responsible for?

  Nourishing the lung parenchyma
• What happens during external respiration?

  Oxygen diffuses from the alveoli into the pulmonary capillaries
• What occurs during internal respiration?

  Oxygen diffuses from systemic capillaries into tissues