Trachea

Function

The trachea is a 10–12 cm windpipe kept perpetually open by 16–20 C-shaped cartilage rings, the open side facing posteriorly where the soft membranous wall shares the oesophagus' company. The smooth muscle spanning that gap lets coughing narrow the lumen to jet mucus upward.

Its ciliated pseudostratified epithelium is a living escalator: each of its 10^9 cilia beats 12–15 times per second, driving the mucus blanket — with its trapped dust and microbes — up to the larynx at ~1 cm per minute. Warm (37 °C), humidified (100% RH) air is delivered to the lungs whatever the weather outside.

Blood supply

Inferior thyroid arteries (upper) and bronchial arteries (lower).

Nerve supply

Vagus (recurrent laryngeal branch) and sympathetic fibres; cough receptors pepper the mucosa.

Clinical relevance

Tracheal stenosis

Intubation cuffs and tracheostomies scar the cartilage rings, narrowing the airway breath by breath.

Foreign body aspiration

The right main bronchus's steeper, wider course traps inhaled objects on the right — bronchoscopy retrieves them.

Related conditions

• Acute bronchitis
• Influenza (flu)