1. Assessing Breathing Models Lesson 10

2. Breathing, or ventilation, is the process through which the respiratory system moves air into and out of the lungs.

3. Breathing/ ventilation is not the same thing as respiration. Respiration refers to cellular respiration which is a metabolic activity in which the energy needed to support life is released. (carbon dioxide and water are the waste products of cellular respiration.

4. The respiratory system and the circulatory system are both needed for cellular respiration. The respiratory system delivers oxygen to the blood stream and the circulatory system transports nutrients and oxygen to the cells and carries away waste product.

5. The respiratory system transports carbon dioxide out of the body during exhalation.

6. Steps in the breathing process Inhalation The diaphragm is a broad, think muscle that separates the chest cavity from the abdomen. During inhalation, the diaphragm contracts and moves downward, increasing the size of the chest cavity

7. The intercostal, or rib muscles, also contract and cause the ribs to move upward and outward. This contraction serves two purposes: A. It increases the volume of the chest cavity B. It reduces the air pressure in the lungs.

8. During inhalation, the walls of the lungs are pulled outward. Because the air pressure is now higher outside the lungs than inside, air rushed into the lungs through the mouth and trachea

9. Exhalation Three main things happen during exhalation A. The intercostal muscles relax B. The volume of the chest cavity decreases C. Internal air pressure increases All of these serve to force air out of the lungs.

10. In the breathing process, oxygen and carbon dioxide are exchanged between the lungs and the bloodstream by diffusion. Oxygen is moved into the lungs during inhalation and carbon dioxide is removed during exhalation.

11. The bloodstream carries carbon dioxide to the lungs from the body cells and delivers oxygen from the lungs to the body cells.

12. The lungs are enclosed in a double layered membrane, called the pleura. Between the two layers is a narrow space called the pleural cavity, which is filled with pleural fluid. The fluid helps the lungs glide easily against the chest wall during breathing.