📗 Lectura

The purpose of the respiratory system is to perform gas exchange. Pulmonary ventilation provides air to the alveoli for this gas exchange process. At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.

• Ventilation: Is the process of inhaling and exhaling, with oxygen entering the alveoli (large surface area).
• Gas exchange: Process of exchanging one gas for the other between the alveoli and capillaries. (Carbon dioxide for oxygen).
• Cell Respiration: The chemical process occurring in the mitochondria where energy is released as ATP.

A ventilation system is needed in order to obtain oxygen for living organisms and to get rid of carbon dioxide. Surface diffusion utilized by many smaller organisms is not sufficient in supplying the oxygen needs of the body. It is also needed to maintain a concentration gradient in the alveoli.

Because gas exchange is a passive process, a ventilation system is needed to maintain a concentration gradient in alveoli. Oxygen is consumed by cells during cellular respiration and carbon dioxide is produced as a waste product. This means oxygen is constantly being removed from the alveoli into the bloodstream (and CO2 is continually being released)

The lungs function as a ventilation system by continually cycling fresh air into the alveoli from the atmosphere. They also have a large surface area to increase the rate of gas exchange.