Topic 2. Oral Cavity and Teeth

Topic 2. Oral Cavity and Teeth

List of words borrowed from Latin and Greek

alveolus membrane

alveoli molar

buccal premolar

canine muscle

cavity nerve

cementum nervous

cuspid permanent

*bicuspid *transient

deciduous periodontium

dentin periodontal

enamel periosteum

fluid pulp

gastrointestinal saliva

gland salivary

implant substance

incisor tissue

lymph utilize

mandible uvula

maxilla vessel

maxillae vascular

The oral cavity is a part of the gastrointestinal tract and is sometimes called the buccal cavity. It is formed by the hard palate and the soft one. The cheeks form the walls of the cavity and the lips form the opening to it. The tongue extends across the floor of the oral cavity and is attached by muscles to the mandible (lower jaw bone). The teeth are implanted on the borders of the upper and lower jaw bones. The gums made of fleshy tissues surround the sockets in which the teeth are found.

Two sets of teeth are developed during the life. The first set is the milk or deciduous teeth. These develop shortly after the seventh month usually and are lost during childhood, when the second set of teeth or permanent ones appear.

There are 32 permanent teeth, 16 in each jaw bone. They differ from each other in form, hence, in their use. The front teeth, or incisors, eight in number, are sharp and serve for cutting and tearing. The back teeth, eight premolars or bicuspids and twelve molars, have large bases or crowns utilized in grinding and crushing the food. There are also two cuspids, or canines, in each jaw bone.

A tooth consists of a crown, which is above the gum, a neck, and a root, which is embedded in an alveolus, or tooth socket. The outer most protective layer of the crown is called the enamel. The enamel is a dense, hard, white substance – the hardest substance in the body. Underneath the enamel is a layer, which extends throughout the crown and root and forms the main bulk of the tooth; it is called the dentine. The dentine is composed of the bony tissue and is covered by a protective layer of cementum. Below the dentine is a soft, vascular layer in the center of the tooth called pulp. Within the pulp are blood vessels, connective tissue, nerve endings, and lymph vessels. The periodontal membrane, or dental periosteum, surrounds the root and holds the tooth in place.

There are three pairs of salivary glands in the oral cavity, which produce a fluid called saliva.

Nouns: Verbs:

border to appear

bulk to attach

cheek to cut (cut, cut)

crown to crush

gum to develop

jaw to differ (from)

layer to embed

lip to extend

neck to grind (ground, ground)

opening to hold (held, held)

palate to lose (lost, lost)

pair to protect

root to surround

set to tear (tore, torn)

socket

tongue

Adjectives:Prepositions:

fleshy above

soft below

sharp throughout

protective underneath

within

Adverb:

hence

1. What is the oral cavity formed by?

The oral cavity is formed by hard and soft palates, cheeks and lips.

2. Where are the teeth implanted?

The teeth are implanted on the borders of upper and lower jawbones.

3. How many sets of teeth are there? What do we call them?

There are two sets of teeth. The first set is milk or deciduous teeth. The second set is permanent teeth.

4. How many teeth does a normal man have? What are they?

A normal man has thirty-two permanent teeth. They are eight incisors, four cuspids or canines, eight bicuspids or premolars, and twelve molars.

5. What parts does a tooth consist of?

A tooth consists of a crown, a neck, and a root.

6. Which layer is the most protective layer of the crown?

The most protective layer of the crown is enamel.

7. What layer is there underneath the enamel?

There is dentin underneath the enamel.

8. What is cementum?

Cementum is a protective layer covering the dentine.

9. What is the pulp?

The pulp is a soft vascular layer in the center of the tooth, containing blood vessels,

connective tissue, nerve endings and lymph vessels.

10. How many salivary glands are there in the oral cavity?

There are three pairs of salivary glands in the oral cavity, which produce saliva.

Дата добавления: 2015-11-04