24 - liquid oral environment - definition. Sal

Liquid oral environment definition

• Liquid in the oral cavity, washes over the mucosa and enamel. It consists of saliva, gingival fluid, peeling epithelial cells and products, microorganism and products

What is saliva?

A complex fluid that represent the immediate

Function of saliva

• Moistens mouth and lubricates food

• Facilitates speech

• Helps with taste by acting as a solvent for food molecules and acts as a buffer to maintain pH of oral cavity

• Contains digestive enzymes - amylase

• Cleanses the mouth, contains antibodies and antimicrobial substances

Composition of saliva

• 600-1000 ml a day, 99% is made up of water

• Electrolytes

• secretory proteins

• immunoglobulins - IgA, IgG, IgM

Cellular composition

• basic secretory units - acini, serous acini, mucous acini

• Epithelial cells

• Neutrophils

• Lymphocytes

• Bacterial flora

Formation and secretion of saliva

• produced by salivary glands, acini are located in them, they can be mucous or serous

• Serous cells - secrete watery enzyme rich fluid

• Mucous cells - secrete mucus for lubrication

• Myoepithelial cells - contractile cells which help propel saliva in oral cavity

Structure of salivary glands

• lobular organisation - lobules divided by thick portions of connective tissue known as septae

Organisation from main excretory duct (empties into oral cavity) to spherical end piece (salivary gland)

1. main excretory duct

2. excretory duct

3. striated duct

4. Intercalated duct

5. Tubular secretory end piece

6. Spherical secretory end piece

Regulation of salivary secretion

1. thought, sight, smell, taste

2. Facial nerve and glossopharyngeal nerve send input to higher brain centres

3. Sending impulse to submandibular, otic (optic?) and cervical ganglions which further send these impulses to make the salivary glands produce saliva