RESPIRATORY SYSTEM: EXCHANGE OF GASES

What is its role? Provides O2 needed by the body Removes CO2 produced by body Works closely with the circulatory system

The Four Processes of the Respiratory System: Breathing: air in to and out of lungs External respiration: gas exchange between air and blood (occurs in lungs) Internal respiration: gas exchange between blood and tissues (occurs in body capillaries) Cellular respiration: oxygen used to produce ATP, carbon dioxide is waste (occurs in cells)

Human Respiratory System Figure 10.1

Components of the Upper Respiratory Tract Figure 10.2

What does the Upper Respiratory tract do? Passageway for respiration Receptors for smell Filters incoming air to filter larger foreign material Moistens and warms incoming air Resonating chambers for voice

Components of the Lower Respiratory Tract Figure 10.3

What does the Lower Respiratory Tract do? Larynx: maintains an open airway, routes food and air appropriately, assists in sound production Trachea: transports air to and from lungs Bronchi: branch that leads into lungs Lungs: transport air to alveoli for gas exchange Alveoli : site where gas exchange occurs with the capillaries

Gas Exchange Between the Blood and Alveoli Figure 10.8A

How do we breathe? Figure 10.9

Disorders of Respiratory System Reduced air flow: Asthma – inflammation of airwaves Emphysema – destruction of tissues around alveoli Infections: Bronchitis – bacterial infection of bronchi and bronchioles Pneumonia – many causes, alveoli fill with fluid Tuberculosis – M. tuberculosis infection of alveoli SARS – Viral infection of lungs, near pandemic in 2003 Cancer – smoking is a major cause of lung, mouth, esophagus, larynx, pancreatic, and bladder cancer Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites, and chemical or physical injury to the lungs. Its cause may also be officially described as unknown when infectious causes have been excluded.

Respiration in Fish Gills exchange gases that are dissolved in water Gills are lined with capillaries, just like lungs Fish may open and close their mouths to ensure water flow Other fish need to move constantly