Question

Why are the cartilage rings in the trachea c-shaped?

Answer 1

Hint: The trachea is a windpipe, which is a passage reaching from the primary bronchi of the lungs to the larynx or voice box. It allows air to travel from and to the lungs. In human adults, the trachea is roughly 1.5 to 2 centimeters in diameter and 4 inches in length. The trachea is classified into two smaller tubes known as bronchi. One bronchus is present in each lung. The trachea moistens and warms the air, as it passes through the lungs.

Complete answer

                                       Fig: Trachea and Cartilage Rings
The trachea contains ciliated pseudostratified columnar epithelium-lined tubular structures supported by rings of hyaline cartilage. The cartilage rings present in the trachea are c-shaped because the trachea passes through the esophagus. The rings prevent collapsing in the absence of air. There are 15 to 20 incomplete c-shaped cartilaginous rings present in humans. The rings prevent the trachea from collapse. They are incomplete because this permits the trachea to collapse slightly to allow food to pass down the esophagus. They reinforce the lateral and anterior sides of the trachea for protecting and maintaining the airway. They are not O-shaped due to the trachea’s proximity to the esophagus, which runs behind the trachea. The open part of the cartilage rings faces the esophagus, permitting the trachea to be compressed slightly when the esophagus bulges outward when the food is swallowed.

Note:
Hyaline cartilage offers structural support to the trachea, bronchi, and larynx in the respiratory system. It holds the airway of the trachea open through cartilage rings. The perichondrium is a layer of dense irregular connective tissue, surrounding the cartilage. Two or more cartilage rings are united, partially or completely bifurcated. When food or liquid passes through the esophagus, the rings allow the expansion of the esophagus.