The document summarizes key aspects of the respiratory system in 3 paragraphs or less: 1) The respiratory system performs ventilation through breathing, gas exchange between air and blood in the lungs, and cellular respiration utilizing oxygen. Partial pressures and composition of gases change as air moves through the respiratory tract. 2) The conducting zone includes nasal passages and pharynx that warm and cleanse air before it reaches the lungs. The lungs contain alveoli with a large surface area for efficient gas exchange. 3) Breathing is regulated by brainstem centers that control the muscles of inspiration and expiration in response to chemoreceptors monitoring blood gas levels, maintaining homeostasis. Gases are transported via hemoglobin in red blood

1. RESPIRATORY SYSTEM

7. Respiratory Anatomy

8. Nasal passages & Pharynx trachea esophagus nasopharynx (food) (air)

10. Trachea Next Slide

12. Mechanics of Respiration Ventilating the Lung - getting air into and out of the lung Inspiration and Expiration

14. This principle governs the movement of air into and out of the lung. Muscles of inspiration shown in the next slide cause the thoracic cavity to expand and the lung is “pulled” open, thus reducing the air pressure in the lung. Since the pressure in the air around us (atmospheric pressure) is higher, air will move from the region of higher pressure to the region of lower pressure, and fill the expanding lung. Expiration at rest is a rather “passive” process and relies on the elastic recoil of the lung and thoracic wall to reduce the size, increase the pressure in the lung (“intrapulmonic”), and force the air out. During exercise, muscles contract more forcefully, and the process is more “active”.