1: Gas Exchange

1. nostrils: opening to the nasal passages

2. nasal passages: lined with a mucus membrane bearing cilia (warms, moistens, and filters incoming air)

3. pharynx (throat)--cavity in back of mouth

4. glottis: windpipe or trachea opening

epiglottis--muscular flap covering the glottis--prevents food from entering the windpipe

5. larynx (voice box) upper part of the windpipe containing sound producing vocal cords

6. trachea: (windpipe)--about 4 inches long & 1 inch in diameter --supported by rings of cartilage --lined with a ciliated mucus membrane which filters incoming air

7. bronchi: two main branches of trachea which enter lungs --lined with cartilage and ciliated

8. bronchioles: smallest air tubes which end at the alveoli or air sacs --cartilage ring support "fades out"

9. alveoli (air sacs): site of respiratory gas exchange by diffusion --resemble bunches of grapes --moist surface aids exchange--each alveolus is surrounded by capillaries & gas exchange occurs with them (oxygen in--carbon dioxide out)

The purpose of getting in oxygen is to get it through our bloodstream to the cells of our body.

At our cells it combines with glucose food to form usable ATP energy (cell respiration).

** The capillaries which surround the alveoli are involved in gas exchange between the blood and the alveoli. In the blood, oxygen is carried by the red blood cell as oxyhemoglobin. Oxygen, which is loosely bound to the hemoglobin, diffuses into the cells where it is used during aerobic cellular respiration.

** The end products of aerobic cellular respiration, water and carbon dioxide diffuse into the blood. Then these waste gases are released from the lungs.

diaphragm: sheet of muscle separating the thoracic (chest) cavity from the abdominal cavity

breathing--the mechanical part of respiration ... involves both the diaphragm and rib cage muscles

(Some Respiratory System Malfunctions)

1. pneumonia: alveoli fill with fluids and mucus resulting in coughing and breathing difficulties

2. asthma: allergic reaction in which bronchiole contractions create breathing difficulties

3. emphysema: air sacs lose their elasticity and breakdown resulting in a loss of respiratory surface in the lungs --shortness of breath is the chief symptom (smoking frequently leads to this disorder