Salivary glands  Saliva is produced in and secreted from salivary glands.  The basic secretary units of salivary glands are clusters of cells called an Acini.  3 major types of salivary glands are present.

 Parotid glands produce a watery secretion  Submaxillary (mandibular) glands produce a mixed watery and mucous secretion  Sublingual glands secrete a saliva that is predominantly mucous in character

Composition  Water Water  Electrolytes: Electrolytes  2-21 mmol/L sodium (lower than blood plasma)sodiumblood plasma  mmol/L potassium (higher than plasma)potassium  mmol/L calcium (similar to plasma)calcium  mmol/L magnesiummagnesium  5-40 mmol/L chloride (lower than plasma)chloride  25 mmol/L bicarbonate (higher than plasma)bicarbonate  mmol/L phosphatephosphate  Mucus. Mucus  Antibacterial compounds (thiocyanate, hydrogen peroxide, and secretory immunoglobulin Athiocyanatehydrogen peroxideimmunoglobulin A

 Various enzymes. There are three major enzymes found in saliva.enzymes  α-amylase Amylase starts the digestion of starch and lipase fat before the food is even swallowed. It has a pH optima of 7.4.amylasepH  lingual lipase. Lingual lipase has a pH optimum ~4.0 so it is not activated until entering the acidic environment of the stomach. lingual lipasepH  Antimicrobial enzymes that kill bacteria. Antimicrobial  Lysozyme Lysozyme  Salivary lactoperoxidaselactoperoxidase  Lactoferrin [10] Lactoferrin [10]  Immunoglobulin A [10] Immunoglobulin A [10]  Proline-rich proteins (function in enamel formation, Ca 2+ -binding, microbe killing and lubrication) [10] Prolineenamel [10]

 Cells: Possibly as much as 8 million human and 500 million bacterial cells per mL. The presence of bacterial products (small organic acids, amines, and thiols) causes saliva to sometimes exhibit foul odor.foul odor  Opiorphin, a newly researched pain-killing substance found in human Opiorphin  Outputs range from 0.75 liters per day to 1.5 liters per day  Secretion of saliva is under control of the autonomic nervous system, which controls both the volume and type of saliva secreted.

Functions  Lubrication and binding: the mucus in saliva binds to food and make it into a slippery bolus that (usually) slides easily through the esophagus without inflicting damage to the mucosa.  Saliva also coats the oral cavity and esophagus, and food basically never directly touches the epithelial cells of those tissues.  Solubilizes dry food: in order to be tasted, the molecules in food must be solubilized.

 Oral hygiene: The oral cavity is constantly flushed with saliva, which floats away food debris and keeps the mouth relatively clean. Flow of saliva diminishes considerably during sleep, allow populations of bacteria to build up in the mouth -- the result is dragon breath in the morning.  Saliva also contains lysozyme, an enzyme that lyses many bacteria and prevents overgrowth of oral microbial populations.

 Starch digestion: in most species, the serous acinar cells secrete an alpha-amylase which can begin to digest dietary starch into maltose.  Provides alkaline buffering

 It is a fluid of the respiratory tract  Consist of tracheobronchial secretions contaminated with:  Epithelial cells  Nasal secretions  Saliva  Bacteria

 Produced by surface epithelial cells and submucous glands.  Contain mixture of :  Plasma  Water  Electrolytes  Mucin

Composition  95% water  5 % solids including:  Carbohydrates  Proteins ( enzymes, immunoglobulins)  Lipids  DNA from broken WBC  Macrophages  Bronchial epithelial cells

Characteristics  Viscoelastic secretion due to the presence of sialic acid.  Normal sputum is colorless and clear  Yellow color if puss is present as in pneumonia  Rusty color may be due to decomposed heamoglobin  Red color if there was recent haemorrhage as in cardiac failure, pulmonary infection, or tuberculousis

 Normally its odorless unless there is lung abscesses, gangrene, or tuberculosis.  Odor can change in the presence of bacteria.

Microscopic examination Bronchial asthma (Allergy):  Sputum is white and mucoid  NO RBC  No pus  During infection, Eosinophils and neutrophils are present in large number

Chronic bronchitis:  Increased histocytes and monocytes  Increased leucocytes and epithelial cells  Increased LDH activity  High DNA level due to cellular damage

Pneumonia: Can be due to gram- positive or gram- negative Bacteria: 1. Gram – positive:  The pathogen is Streptococcus  The sputum is less volume and transparent with some blood flakes  Later it becomes rusty red containing RBC, WBC, and epithelial cells

2. Gram – negative:  Pathogens are Enterobacter, Pseudomonas, Eschercia Coli  Sputum is green in color