Anatomy and Physiology

Out with the old and in with the new—that's what the respiratory system does, delivering air to the lungs, bringing oxygen into the body, and expelling the carbon dioxide back into the air. Understanding the structure and intricacies of the respiratory system is vital to human anatomy. The respiratory system is made up of more than just the lungs; it also includes your nose, throat, larynx, windpipe, bronchi, alveolar ducts, and respiratory membrane.

The function of the respiratory system is to deliver air to the lungs. Oxygen in the air diffuses out of the lungs and into the blood, while carbon dioxide diffuses in the opposite direction, out of the blood and into the lungs. Respiration includes the following processes:

• External respiration is the process of gas exchange between the atmosphere and the body tissues. In order to accomplish this task, the following events occur:

  1. Pulmonary ventilation is the process of breathing—inspiration (inhaling air) and expiration (exhaling air).

  2. Gas transport, carried out by the cardiovascular system, is the process of distributing the oxygen throughout the body and collecting CO ₂ and returning it to the lungs.

• Internal respiration is the process of gas exchange between the blood, the interstitial fluids (fluids surrounding the cells), and the cells. Inside the cell, cellular respiration generates energy (ATP), using O ₂ and glucose and producing waste CO ₂.