Respiratory System

Respiratory System

Function of the Respiratory System • To bring about the exchange of oxygen and carbon dioxide between the air, the blood, and the tissues.

Structures of the Respiratory System • Nose/Mouth—warms, moisten, filters inhaled air • Pharynx—food and air together here, passage to trachea • Larynx (voice box)—location of vocal cords • Trachea (wind pipe)—structure to keep airway open, lined with cilia to filter air • Bronchi—(2 of them) one branch to each lung • Lungs (that have bronchioles (smaller branches off bronchi) and alveoli (air sacs where gas exchange occurs) • Diaphragm (muscle at base of rib cage that helps to fill lungs with air)

Path of Air Path of Air to the Lungs --Nose or mouth  Pharynx  Larynx  Trachea  Bronchi • Path of Air Inside the Lungs • Bronchioles  Alveoli • Then air can exit in opposite direction

Gas Exchange • 150 million alveoli (air sacs) in each lung • Oxygen dissolves in the moisture on the inner surface of the alveoli and then diffuses across the capillary wall into the blood stream • Carbon dioxide in the blood moves from the blood to the alveoli and is then exhaled.

Breathing • Movement of air into and out of lungs • No muscle connected to lungs • Air pressure forces air into the lungs • The diaphragm is a muscle at the bottom of the body cavity

Inhaling • The diaphragm moves down  the ribs move up and out  the chest cavity volume increases  creates a partial vacuum inside the body cavity  air is forced in

Exhaling • Diaphragm moves down  the ribs move down and in  volume of chest decreases  internal pressure rises above air pressure outside of body  air is forced out

Disorders of Respiratory Sys • Reduced air flow: asthma, emphysema, bronchitis • Infections: pneumonia, tuberculosis, botulism • Lung cancer • Congestive heart failure • Cystic fibrosis

Four Respiration Processes • Breathing (ventilation): air in to and out of lungs • Cellular respiration: oxygen use to produce ATP, carbon dioxide as waste

Respiratory System