Question

Why the trachea not collapse even of the air pressure is less inside it?

Answer 1

The trachea does not collapse even if the air pressure is less inside it because it has a series of cartilaginous rings which form a relatively rigid arrangement. The C - shaped cartilage rings are present till the trachea bifurcates into the bronchi. The rings are connected to the trachealis muscle which runs down the back of the windpipe. This makes the whole structure look like a half circle. It allows the contents of the oesophagus to pass behind the trachea. This prevents it from collapsing due to pressure changes.

Answer 2

The correct answer is - due to the presence of the cartilaginous C-shaped rings.

The trachea is made up of a series of cartilaginous rings that are incomplete. These incomplete rings form the shape of a ‘C’ and form a rigid arrangement. They help in resisting the collapsing effects due to the positive intra-thoracic pressures during expiration.

Also, these rings have a dorsal gap and the trachea is soft in this place. This weak place is bridged by the trachealis muscle, which when contracted prevents the wall from bulging into the lumen.