Which component is NOT part of the respiratory system?

The heart is not a component of the respiratory system; instead, it is part of the circulatory system. The primary function of the respiratory system is to facilitate the exchange of gases—specifically oxygen and carbon dioxide—between the body and the environment. This system includes structures such as the diaphragm, nose, and trachea, all of which play significant roles in breathing and gas exchange.

The diaphragm is a muscle that aids in the inhalation process by contracting and creating a vacuum that allows air to be drawn into the lungs. The nose serves as the entryway for air and is involved in filtering, warming, and humidifying it before it enters the lungs. The trachea, commonly known as the windpipe, is a flexible tube that connects the throat (pharynx) to the lungs, allowing air to flow in and out during the breathing process. Understanding the distinct roles of these components furthers the comprehension of how the respiratory system operates separately from the circulatory system, which is responsible for circulating blood and nutrients throughout the body.