The Lungs

Pulmonary Ventilation & TB

Pulmonary Ventilation & TB

Ventilation refers to the movement of air into and out of the alveoli.

There are a number of measurements involved with ventilation:

  • The tidal volume is the amount of the air which is inhaled and exhaled in one breath.
  • The functional residual capacity is the volume of air still in the lungs after exhalation of the tidal volume.
  • The expiratory reserve volume is the amount of air involved in a maximal exhalation.
  • The residual volume is the amount of air left in the lung after maximal exhalation.
  • The inspiratory reserve volume is the additional volume of air that can be inhaled after the tidal volume has been inhaled.
  • Vital capacity refers to the most amount of air that can be exhaled from the lungs after they have been maximally filled. This is the best indicator for breathing.

Pulmonary ventilation (the volume of air which ventilates the air each minute) is calculated by:

pulmonary ventilation = ventilation rate x tidal volume



TB can stay dormant for months or even years. They then begin to reproduce within the lung epithelial cells. This kills them, reducing the lung surface area further. It’s possible for the bacteria to spread throughout the body, carried by the blood stream, and destroy other areas like the nervous tissue or the kidneys.

If someone becomes infected the symptoms include chest pains and prolonged coughing which produce sputum. Sometimes people even cough up blood and, in very rare occasions, the pulmonary artery might be broken down causing massive bleeding (known as Rasmussen’s aneurysm). If the tuberculosis become chronic it can lead to damage and scarring of the lungs in the upper lobes. The new sufferer will not become infectious themselves until three or four week after infection.

Today, vaccinations are widely used in children to prevent the infection. Sufferers are treated with a combination of antibiotics. However, there are strains of tuberculosis which are highly drug-resistant.