Respiration and Gas Exchange

Vesicular breath sounds are heard throughout the chest and are best heard at the base of the lungs. They are low pitched soft sounds, best heard during inspiration.

Stridor is the name given to high pitched sounds produced when air passes through a partially obstructed or narrowed upper airway on inspiration. Stridor is associated with respiratory distress and can be life-threatening, because the airway is compromised.

Asthma is a disorder of the bronchial airways characterized by periods of reversible bronchospasm (spasms of prolonged contraction of the airway). Asthma is often called, the reactive airway disease. This complex disorder involves biochemical, immunologic, endocrine, infectious, autonomic, and psychological factors.

Hemoptysis is the expectoration (coughing up) of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs (e.g., in tuberculosis or other respiratory infections or cardiovascular pathologies).

Expiratory reserve volume is the maximal amount of gas that can be exhaled from the resting end-expiratory level. In a deep and forceful expiration, the lungs are capable of exhaling a volume which is in excess to the tidal volume and the inspiratory reserve volume. This is known as the expiratory reserve volume (ERV). In a healthy young adult ERV is approximately 1.3 – 1.5 litres.

Hyperpnoea is the term used to indicate over breathing or hyperventilation. It is an abnormal increase in the rate and depth of breathing.

About 70% of carbon dioxide is transported as bicarbonate ions (HCO3-) dissolved in plasma. CO2 enters red blood cells, is converted to carbonic acid by carbonic anhydrase, which dissociates into H+ and HCO3-, with HCO3- moving into plasma.

The hilum of the lung is a triangular part which allows the other structures forming the root of the lung to enter and exit. It permits arteries, veins, nerves, bronchi and other structures to enter and exit.

During the act of expiration, the diaphragm potentially relaxes and the elastic recoil of the lungs, chest wall, and abductor muscles compresses the lungs.

It is the volume of gas remaining in the lungs at the end of a normal tidal expiration. It is the balance point between the inward elastic recoil of the lungs and the outward elastic recoil of the chest wall.

It extends from the base of the skull to the upper surface of the soft palate. It includes the space between the internal nares and the soft palate, and lies above the oral cavity. The adenoids are lymphoid tissue structures located in the posterior wall of the nasopharynx.

Sound is generated in the larynx, and that is where the pitch and volume are manipulated. The strength of expiration from the lungs also contributes to loudness.

Each lung receives air from a single, large primary bronchus. As the primary bronchi enter the lungs, they branch off into smaller secondary bronchi that carry air to each lobe of the lung.

Cough and breathlessness are respiratory symptoms because they affect the lungs and airways. Lung infections like pneumonia or bronchitis directly cause these symptoms as the respiratory system struggles to function properly. The brain, liver, and kidneys are not involved in breathing or coughing reflexes.

This is correct.