The document describes the respiratory system and its functions. It explains that respiration involves breathing to intake oxygen and release carbon dioxide through two processes - breathing and cellular respiration. The respiratory system includes the nose, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. Breathing is powered by the diaphragm and rib muscles to diffuse oxygen into red blood cells and transport it to tissues through cellular respiration. Some respiratory disorders mentioned are asthma, emphysema and SARS.

1. Life Science 2.4The Respiratory System

2. Objectives:Describe the parts of the respiratory system and their functions.Explain how breathing happens.Discuss the relationship between the respiratory system and the cardiovascular system.Identify two respiratory disorders.

3. Respiration and the Respiratory SystemRespiration Process by which a body gets and uses oxygen and releases carbon dioxide and water. Breathingis only one part of respiration.Cellular respiration Second part of respiration.Involves chemical reactions that release energy from food.Respiratory systemGroup of organs that take in oxygen and get rid of carbon dioxide.

5. Nose, Pharynx, and Larynx Your nose is the main passageway into and out of the respiratory system. From the nose, air flows into the pharynx, or throat. The larynx is the part of the throat that contains the vocal chords.

6. TracheaThe larynx guards the entrance to a large tube called the trachea, or windpipe.Bronchi and Alveoli The trachea splits into two branches called bronchi.One bronchus connects to each lung. In the lungs, each bronchus branches into bronchioles, which branch to form thousands of tiny sacs that are called alveoli.

7. BreathingBreathing is done by the diaphragm and rib muscles.The diaphragm is a dome-shaped muscle beneath the lungs.In cellular respiration, oxygen is used by cells to release energy stored in molecules of glucose. When you breathe, you take in oxygen, which diffuses into red blood cells and is carried to tissue cells.Breathing and Cellular Respiration

8. Respiratory DisordersRespiratory disorders include asthma, emphysema, and severe acute respiratory syndrome (SARS).Asthma causes the bronchioles to narrow. An asthma attack may be triggered by irritants such as dust or pollen.SARS is caused by a virus.