Pleura

• Thorax: Thorax can be divided into

  • Right pleural cavity

  • Left pleural cavity

  • Mediastinum

• Pleural: Each lung is encapsulated within a pleural cavity, the pleura fills with remaining space in the thorax not taken up by the mediastinum. No connection between the two pleura.

The Respiratory Tract

• Overview: Begins at the nose/nasal cavity where air enters, passes into the pharynx and enters two tubes down into the thorax to the windpipe and trachea. Continues down into the lungs where it divides into further bronchioles, bronchi which go into the alveolar, then alveolar sacs where gas exchange occurs.

• Upper: The nose takes in air and specialized structures of bone and epithelial tissue within nasal cavities called concha that is curved to allow air to flow through them into the pharynx (increases surface area) and the epithelium is specialized in humidifying area. Hair is present which can capture large pathogens with the addition of mucus that can break them down. The epiglottis covers the trachea preventing food from passing through it.

• Pleural: Each lung is encapsulated within a pleural cavity, the pleura fills with remaining space in the thorax not taken up by the mediastinum. No connection between the two pleura.

• Trachea: A flexible, hollow tube that extends from about C6 to T4/T5 (Angle Of Louie) it forks down to two paths, starting from the cricoid cartilage. It’s surrounded by C-shaped cartilaginous rings. Airways are always open but can get blocked.

• Lungs: Both lungs have an apex that projects above rib 1 and into the neck and has a base that sits on the diaphragm

  • Right: 3 lobes - Superior, Middle, and Inferior. Divided by oblique and horizontal fissures, shorter and wider than the left lung.

  • Left: Superior and inferior. Divided by an oblique fissure, it has a distinct cardiac notch and lingula (tongue-shaped region).

• Hilum: Structures from the mediastinum enter and leave the lungs at the hilum. These include the pulmonary artery as well as the pulmonary vein, main bronchus, bronchial vessels, nerves, and lymphatics. The structures also help anchor the lung in the mediastinum and support it.