The respiratory system

Airways and Lungs

  1. Introduction
  2. Slides
  3. Test


The respiratory system

The respiratory system is divided into a conducting section and a respiratory section.

The conducting section consists of the:

and is responsible for conducting air to the lungs.

The respiratory section consists of the:

and is responsible for gaseous exchange

The conducting section

The respiratory section

General histology of the lungs

Lung lobules are pyramid shaped, with an apex (towards the hilum) and a basis (towards the surface of the lungs).

The branches of the pulmonary artery follows the branching of the bronchi and bronchioles. In the interalveolar septae these blood vessels become capillaries that merge to form interlobular veins.

The pleura covers the lungs. It has two layers, parietal and visceral. Both membranes are composed of mesothelial cells resting on a fine connective tissue layer with collagen and elastic fibres. These two layers define a cavity lined entirely with mesothelial cells which is filled with a thin layer of fluid.

Medical fact: The walls of the pleural cavity are very permeable to water and other substances, and therefore fluid accumulation (pleural effusion) occurs frequently.


Nostril Slide 71
Very low magnification

Fig 71-001

Olfactory epithelium Slide 108
Very low magnification of olfactory epithelium
Fig 108-001 Fig 108-002 Fig 108-003

Epiglottis Slide 111
Fig 111-001

Trachea Slide 73
Fig 73-001 Fig 73-002 Fig 73-003

Lung Slide 74 & Slide 72K
Very low magnification of the lung

Very low magnification of the lung

Fig 74-002 Fig 74-003 Fig 74-004 Fig 74-005
Fig 74-007 Fig 72-001 Fig 72-002


© februarie 2005 marius loots