FUNCTIONAL ANATOMY OF MOUTH

FUNCTIONAL ANATOMY OF MOUTH

Mouth is otherwise known as oral cavity or buccal cavity. It is formed by cheeks, lips and palate. It encloses the teeth, tongue and salivary glands. Mouth opens anteriorly to the exterior through lips and posteriorly through fauces into the pharynx. Digestive juice present in the mouth is saliva, which

is secreted by the salivary glands.

FUNCTIONS OF MOUTH

Primary function of mouth is eating and it has few other important functions also.

Functions of mouth include:

1. Ingestion of food materials

2. Chewing the food and mixing it with saliva

3. Appreciation of taste of the food

4. Transfer of food (bolus) to the esophagus by swallowing

5. Role in speech

6. Social functions such as smiling and other expressions.

SALIVARY GLANDS

In humans, the saliva is secreted by three pairs of major (larger) salivary glands and some minor (small) salivary glands.

MAJOR SALIVARY GLANDS

Major glands are:

1. Parotid glands

2. Submaxillary or submandibular glands

3. Sublingual glands.

1. Parotid Glands

Parotid glands are the largest of all salivary glands, situated at the side of the face just below and in front of the ear. Each gland weighs about 20 to 30 g in adults. Secretions from these glands are emptied into the oral cavity by Stensen duct. This duct is about 35 mm to 40 mm long and opens inside the cheek against the upper second molar tooth.

2. Submaxillary Glands

Submaxillary glands or submandibular glands are located in submaxillary triangle, medial to mandible.

Each gland weighs about 8 to 10 g. Saliva from these glands is emptied into the oral cavity by Wharton duct, which is about 40 mm long. The duct opens at the side of frenulum of tongue, by means of a small opening on the summit of papilla called caruncula sublingualis.

3. Sublingual Glands

Sublingual glands are the smallest salivary glands situated in the mucosa at the floor of the mouth. Each

gland weighs about 2 to 3 g. Saliva from these glands is poured into 5 to 15 small ducts called ducts of Rivinus. These ducts open on small papillae beneath the tongue. One of the ducts is larger and it is called Bartholin duct . It drains the anterior part of the gland and opens on caruncula sublingualis near the opening of submaxillary duct.

MINOR SALIVARY GLANDS

1. Lingual Mucus Glands

Lingual mucus glands are situated in posterior one third of the tongue, behind circumvallate papillae and at the tip and margins of tongue.

2. Lingual Serous Glands

Lingual serous glands are located near circumvallate papillae and filiform papillae.

3. Buccal Glands

Buccal glands or molar glands are present between the mucus membrane and buccinator muscle. Four to

five of these are larger and situated outside buccinator, around the terminal part of parotid duct.

4. Labial Glands

Labial glands are situated beneath the mucus membrane around the orifice of mouth.

5. Palatal Glands

Palatal glands are found beneath the mucus membrane of the soft palate.

CLASSIFICATION OF SALIVARY GLANDS

Salivary glands are classified into three types, based on the type of secretion:

1. Serous Glands

Serous glands are mainly made up of serous cells. These glands secrete thin and watery saliva. Parotid glands and lingual serous glands are the serous glands.

2. Mucus Glands

Mucus glands are mainly made up of mucus cells. These glands secrete thick, viscous saliva with high

mucin content. Lingual mucus glands, buccal glands and palatal glands belong to this type.

3. Mixed Glands

Mixed glands are made up of both serous and mucus cells. Submandibular, sublingual and labial glands are the mixed glands.

STRUCTURE AND DUCT SYSTEM OF SALIVARY GLANDS

Salivary glands are formed by acini or alveoli. Each acinus is formed by a small group of cells which surround a central globular cavity. Central cavity of each acinus is continuous with the lumen of the duct. The fine duct draining each acinus is called intercalated duct. Many intercalated ducts join together to form intralobular duct. Few intralobular ducts join to form interlobular ducts, which unite to form the main duct of the gland. A gland with this type of structure and duct system is called racemose type (racemose = bunch of grapes).

  

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