Essay On Salivary Colonies

SALIVARY GLANDS

Although classed as accessory organs to the alimentary canal. Saliva plays a vital part in chemical digestion of ingested food in the mouth. The mouth is lined with a mucous stratified epithelial membrane, reflecting the wear and tear associated with this area. There are three different types of gland situated within the mouth. The parotid glands are the largest saltatory glands, but are responsible for only 25% of daily secretions. Their cells are specialized and for contributing to the watery and enzyme and antibody rich component of saliva. They are positioned just below and in front of the ears and their ducts (called Stenson`s ducts) open at a point opposite the second upper molar teeth.
The submandibular glands are positioned under the base of the tongue in the posterior aspects of the mouth, opening behind the lower central incisors. Their ducts (called Wharton`s ducts) extend centrally along the floor of the mouth. They are responsible for the production of 70% of the daily production of saliva. Their cells function in a similar way to the parotid cells, but they also secrete mucous and so produce a more viscous secretion. The sublingual glands are the smallest of the paired glands and are responsible for 5% of the daily production of saliva.

Also the absence of cartilage from the posterior surface of the trachea helps to reduce friction as the food passes down the oesophagus. The presence of cartilage would make swallowing extremely difficult and uncomfortable. The swallowing process involves a triad of responses

The voluntary stage – the tongue voluntarily moves the bolus of food to the back of the mouth, and then into the oropharynx. This involves the tongue rising and pushing itself against the soft