The Respiratory System 9 Biology

Vocabulary Breathing Gas exchange Lungs Alveoli Capillary bed Inhalation Exhalation Diffusion

Importance of Respiratory System Sustains cellular respiration by supplying oxygen and removing carbon dioxide. Two Components: 1. Breathing- mechanical movement of air into and out of the lungs 2. Gas exchange External: exchange of gases between atmosphere and blood Internal: exchange of gases between blood and body cells

Turn to your neighbor: Discuss the difference between gas exchange and breathing.

Anatomy of Respiratory System

Structures: Nose pharynx larynx trachea Bronchus bronchioles alveoli Capillary beds in alveoli are where gases are exchanged.

Alveoli Thin walled cells surrounded by thin capillaries O2 diffuses in, CO2 diffuses out CO2 in blood exists as carbonic acid dissolved in plasma, bound to hemoglobin

Turn to your neighbor: Explain why the O2 diffuses into the capillary beds of the alveoli and why CO2 diffuses out.

Mechanics of Breathing: Inhalation- diaphragm goes down to allow filling of lungs Exhalation- diaphragm goes up to push air out of lungs Intercostal muscles (between ribs) assist with process

Respiratory Disorders Asthma- airways swell, restricting air flow Bronchitis- airways become infected Emphysema- alveoli break down, reducing surface area for gas exchange Pneumonia-infection of lungs that causes mucous to collect in alveoli Pulmonary tuberculosis- bacterial infection that reduces capillary absorption Lung cancer- uncontrolled cell growth in lungs that causes coughing, shortness of breath, pneumonia, infection and death.

Respiratory Disorders