• Air passes through a series of tubes before gas exchange takes place across a very extensive moist surface.

1. What is the path of air and what are the functions of the organs mentioned?
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2. What are the four steps comprising respiration?
   Answer
   
   
3. How is the air that is inhaled or exhaled modified by the respiratory system?
   Answer

• Human Breathing

Art Labeling Activity

• The Respiratory Tract (38.0K)
• The Respiratory Tract II (40.0K)
• The Upper Respiratory Tract (35.0K)
• The Upper Respiratory Tract II (34.0K)
• Section of Larynx (45.0K)
• Glottis Function (35.0K)

• Respiration comprises breathing, external and internal respiration, and cellular respiration.
  
  
• During inspiration, the pressure in the lungs decreases and air comes rushing in. During expiration, increased pressure in the thoracic cavity causes air to leave the lungs.

1. Why do physicians measure our ability to move air into and out of the lungs? What measurements do they take?
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2. How is breathing achieved? Is pressure within the lungs greatest during inspiration or expiration?
   Answer

• Measuring Function

Animation Activity

• Breathing (860.0K)

• External respiration occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood.
  
  
• Internal respiration occurs in the tissues where oxygen diffuses out of the blood and carbon dioxide diffuses into the blood.
  
  
• The respiratory pigment, hemoglobin, transports oxygen from the lungs to the tissues and aids in the transport of carbon dioxide from the tissues to the lungs.

1. What are the differences between respiration and internal respiration?
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2. What respiratory pigment is found in human red blood cells? What is its function?
   Answer
   
   
3. Why is hemoglobin more saturated with O₂ in the lungs than in the tissues?
   Answer

• Gas Exchange

Animation Activity

• Respiration (1556.0K)
• Hemoglobin (629.0K)
• Gas Exchange (990.0K)

• The respiratory tract is especially subject to disease because it is exposed to infectious agents.
  
  
• Smoking tobacco contributes to three major lung disorders-chronic bronchitis, emphysema, and cancer.

1. What are some common respiratory infections and disorders of the upper respiratory tract? of the lower respiratory tract?
   Answer
   
   
2. What are three disorders commonly associated with smoking tobacco?
   Answer

• Disorders

Case Study

• Asthma: The New Worldwide Epidemic

Animation Activity

• Smoking Risks (1684.0K)
• Asthma (2210.0K)

Art Labeling Activity

• Bronchial and Pulmonary Disorders (39.0K)

• The respiratory system works with the other systems of the body to maintain homeostasis.

1. How does the respiratory system work with the other systems of the body to maintain homeostasis?
   Answer

Bioethical Focus

• Antibiotic Resistance