Anatomy of the respiratory tract

Nostrils - opening to the nasal passages

Nasal passages - lined with a mucus membrane bearing cilia (warms, moistens, and filters incoming air)

Pharynx (throat) - this is a cavity in back of the mouth

Tonsils are located on each wall between the mouth and pharynx

Adenoids are located in rear wall of pharynx behind nasal passages.

The adenoids and tonsils act as bacterial filters - they may become infected and require removal.

Epiglottis - muscular flap covering the glottis, it prevents food from entering the windpipe

Larynx (voice box) - "Adam's apple", upper part of the windpipe containing sound producing vocal cords

Trachea (windpipe) - about 4 inches long and 1 inch in diameter, supported by rings of cartilage and lined with a ciliated mucus membrane which filters incoming air

Bronchi two main branches of trachea which enter lungs --lined with cartilage and ciliated

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

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

Diaphragm - sheet of muscle separating the thoracic (chest) cavity from the abdominal cavity

Breathing - the mechanical part of respiration