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Tuesday, February 24, 2009


ORAL CAVITY:  Anatomy and physiology of GI tract starts from mouth. Mouth is also called oral cavity. Oral cavity consists of
1. Lips
2. Teeth
3. Tongue
4. Hard palate
5. Soft palate
6. Cheeks
7. Uvula
8. Tonsils
9. Gums

CHEEKS AND LIPS:  The cheeks form the walls of the oval-shaped oral cavity, and the lips surround the opening to the cavity.

HARD PALATE:  The hard palate forms the anterior portion of the roof of the mouth. Rugae are irregular ridges in the mucous membrane covering the anterior portion of the hard palate.

SOFT PALATE:  The soft palate is posterior to the hard palate, which is muscular in structure. Uvula is a small and soft tissue hanging from the soft palate. Uvula means little grape. Uvula is helping in producing sounds and speech.

TONGUE:  In the oral cavity tongue extends across the floor of the oral cavity. It attaches in the mouth by muscles to the lower jaw. Tongue moves food around when chewing and swallowing. Chewing action is called mastication, and swallowing action is called deglutition. There are numerous small areas raised on the tongue. They are called papillae, these contain taste buds. Taste buds are sensitive to the chemical materials of food. These buds differentiate various tastes of food as they move across the mouth on the tongue.


The part of the throat near the mouth called oropharynx has mucous membranes. These mucous membranes have depressions on it, and they contain masses of lymphatic tissue called tonsils. These tonsils produces cells called lymphocytes, which protects our body from the invasion of micro-organisms. These lymphocytes are white blood cells. These cells have the ability to fight against diseases.

GUMS:  These are fleshy tissues inside the oral cavity. These tissues surround the teeth sockets. These tissues are called gums.

TEETH:  Teeth are the important part in the oral cavity. Teeth are of many types. By drawing a median line we can divide upper and lower teeth into four arches. Each arch contains eight teeth. Normal adult whether male or female has 32 permanent teeth.

Teeth are of eight types based on their anatomy structure, such as
1. central incisor
2. lateral incisor
3. cuspid or canine
4. first premolar
5. second premolar
6. first molar
7. second molar
8. third molar or wisdom teeth.

The central incisor, the lateral incisor, and the cuspid or canine are nearest teeth to the lips (labi/o means lip). The first premolar, the second premolar, and the first molar are adjacent to cheek surfaces or buccal surfaces (bucc/o means cheek).

The buccal surfaces and lips form the facial surface (faci/o), tongue surface (lingu/o) is against the facial surface and mesial surface and distal surfaces are near and farthest areas to the medial surface. There is also an surface called occlusal surface (occlus/o means to close).

TEETH ANATOMY:  Each teeth consists above the gum a surface called crown and root below the gum within the bony socket of each tooth. Enamel is a layer protects each tooth, this is the outermost layer of the crown, which is hard and dense white substance. This is the hardest substance in the body. Another yellow color substance beneath the enamel extending throughout the crown named dentin. This is composed of bony tissue softer than enamel. This dentin is covered and protected by cementum. Cementum is surrounded by a membrane called periodontal membrane, which holds the tooth in place within the teeth socket. Underneath the dentin is a soft and delicate tissue fills the center of the tooth called pulp. The blood vessels, ending of the nerves, lymph vessels, connective tissues are within this pulp. This canal like structure is called root canal.

SALIVARY GLANDS:  There are three pairs of salivary glands in the oral cavity. Saliva is produced by these glands. Saliva contains enzymes important for digestion of the food. On each side of the mouth three types of salivary glands called parotid, submandibular gland, and sublingual gland. These glands have narrow ducts that carry the saliva into the oral cavity. These salivary glands are exocrine glands as they have ducts.

In the next lesson, we will learn about GASTROINTESTINAL SYSTEM ANATOMY AND FUNCTION..Okay
Come on...

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