2.  Sputum is a secretion produced in the lungs and the bronchi (tubes that carry the air to the lung).  This mucus-like secretion may become infected, blood stained, or contains abnormal cells that may lead to diagnosis

3.  Tracheo bronchial secretions are an inconstant mixture of plasma, water, electrolytes and mucin.  In addition to contamination from upper and lower respiratory tract with cellular exfoliation, nasal and salivary gland secretions and normal bacterial flora of the oral cavity.

4.  Submucous glands: present between the surface epithelium and cartilaginous plates  Surface epithelium: three types of secretory cells can be distinguished: 1. Serous cells 2. Celara 3. Goblet cell: thick mucin-type secretion that is diluted by a more serous mixture of acid glycoproteins, sialoproteins and sulfoproteins are secreted by submucous gland

5.  The physical properties of sputum reveal secretions to be viscoelastic that is some of the properties of liquid and some of solid.  The consistency is dependent mainly on the molecular structure of the glycoproteins and on the degree of hydration.  Sialic acid is the most important single component of sputum viscosity.

6.  Sputum comes up with deep coughing. Increasing the amount of fluids in the night before the test may help to get the sample.  First morning specimen is best, most tracheobronchea secretions are not ejected from the mouth but are swallowed during sleep  Patent cooperation and understanding, instruct patient to rinse mouth with water prior to each collection.  Cough up from deep down in the chest, the specimen should be collected in a sterile container and then send immediately to lab and not be allowed to stand for long time  Specimen expectorated sputum, not saliva or nasal aspirates three consecutive mornings is advisable.

7. Work with sputum collection should always be in safety cabinet

10. 2. Green:  Pseudomon as  Sputum left standing more than 24 hrs tend to become greenish through the break down of neutrophils and the release of neuroperoxi dase enzyme. 3. Rust red:  Decompose d Hb Pneumoco ccal pneumoni a Pulmonary gangrene 4. Bright red  Recent hemorrhage. Acute cardiac failure Pulmonary infection TB Ruptured blood vessels.

11. Acid fast bacteria (mycobacterium tuberculosis )