To better understand whooping cough, it helps to understand the anatomy of the throat, upper airway, and lungs.

The back of throat is also referred to as the pharynx. More specifically, the pharynx is the back, upper part of the throat behind the tongue. It starts at the base of the tongue and ends at the larynx.

Anatomy examples:

• Normal pharynx in an adult
• Normal pharynx in a child
• Normal tongue

The tonsils are collections of lymphoid tissue in the back of the throat. They are located on both sides of the throat, near the base of the tongue. The tonsils generally shrink over time. At puberty, the tonsils are normally about the size of an almond.

Anatomy examples:

• Normal anatomy of the pharynx
• Normal tonsils in a child

Lung Anatomy
Inside the chest, the windpipe, or trachea, divides into two smaller tubes: the right bronchus and the left bronchus. The right bronchus enters the right lung and the left bronchus enters the left lung. The right bronchus and left bronchus branch into smaller and smaller tubes.

The smallest tubes, called bronchioles, end in tiny air sacs, called alveoli. Blood flows very close to the walls of the alveoli. Oxygen and carbon dioxide pass between the air and the bloodstream through the wall of the alveoli.

Anatomy examples:

• The lung and airways
• The bronchioles and alveoli
• The lungs