Question

Rings of ……. present in the trachea, bronchi, and bronchioles prevent their collapse when air is not passing through them.
A. Cartilage
B. Collagen
C. Bone
D. None of the above.

Answer 1

Hint:- Respiratory system is the network of organs or tissues which are essential for breathing. This system helps to absorb oxygen from the air and includes parts such as the nose, mouth, throat, voice box, windpipe, and lungs.

Complete Answer:-
The main organ of the respiratory system is the lungs which help in the exchange of gases. These are pairs of spongy, air-filled organs which are located on either side of the chest or thorax.
The trachea or windpipe is a long wide flexible tube that is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that secrete mucus. The trachea inhales oxygen into the lungs through its tubular branches, known as bronchi. Two primary bronchi are situated inside the lungs, and the right bronchus is slightly larger than the left bronchus, because of this foreign bodies breathed into the lungs also ends up in the right bronchus. Further bronchus branches into smaller tubes called bronchioles. These bronchioles deliver oxygen-rich air to the sac-like structures known as alveoli which are the actual site for the exchange of gases.
In the trachea, tracheal rings or tracheal cartilages are present, these cartilage are strong and flexible tissue. These tracheal rings help support the trachea and preserve its stiffness while it allows the trachea to move and flex during respiration. Generally, sixteen to twenty individual cartilage rings are present which varies from person to person. C-shaped cartilage of trachea is stacked one on another and is open at the area where the trachea is close to the esophagus which leads from throat to the stomach. These rings of cartilage prevent the trachea from collapsing in the absence of air and also aids in protecting it. They stabilize the trachea and make them rigid and allow them to expand when breathing.

So, as we have discussed the correct option is A (Cartilage).

Note:- Respiratory system cleans waste gases from the body such as carbon dioxide from the blood. Oxygen is inhaled and transported to different parts of the body and are used in the breakdown of glucose or burning of food particles at the cellular level.