ANATOMY

Detailed explanation-1: -In your lungs, the main airways, called bronchi, branch off into smaller and smaller passageways. The smallest airways, called bronchioles, lead to tiny air sacs called alveoli.

Detailed explanation-2: -Answer and Explanation: The structures in order from largest to smallest is B. Bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveoli. Air moves through these airways in this order during inhalation to reach the alveoli, where oxygen participates in gas exchange with the blood.

Detailed explanation-3: -It is important to note that the right main bronchus is wider, shorter, and more vertical than the left main bronchus, and it enters the right lung at roughly the level of the fifth thoracic vertebra.

Detailed explanation-4: -Bronchioles are approximately 1 mm or less in diameter and their walls consist of ciliated cuboidal epithelium and a layer of smooth muscle. Bronchioles divide into even smaller bronchioles, called terminal, which are 0.5 mm or less in diameter.

Detailed explanation-5: -There are 20-25 branching generations of conducting bronchioles after the tertiary segmental bronchi. As the bronchioles become smaller in width, they become terminal bronchioles which mark the end of the conducting zone of the respiratory system.