- Category: Digestive system
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Mouth has 2 parts:
1) oral vestibule
2) proper oral cavity.
1. Vestibule of oral cavity is the space bounded by the upper and lower lips, cheeks (front) and also by teeth and gums (rear).The upper lip is bounded by basis of nose and pair nasolabial sulcus; lower lip is bounded by chin-lip sulcus. Lips are formed by circular muscle of the mouth, which is covered with skin on the outside and by mucous membrane on inside. There are skin part of the lip, intermediate - red border, mucous. In the transition from the upper lip to the alveolar bone of the upper jaw mucous membrane forms a fold - the bridle of upper lip; in the transition from the alveolar part of lower lip to the lower jaw mucous membrane forms a fold - bridle of lower lip. Between the lips is oral cleft. Cheek is bounded in above by zygomatic arch, in bottom – by edge of the lower jaw, in front – by nasolabial sulcus, in behind - by chewing muscles. The basis of cheek is buccal muscle lined with mucous membrane inside, and the outside is covered with skin. In cheek is pronounced subcutaneous fat, which forms the fat body of cheeks.
2. Proper oral cavity is bounded by the upper and lower walls. The upper wall is a palate. There are:
- hard palate, formed by palate bone and mucous membrane that covers the bone palate;
- soft palate, formed by muscles and mucous membrane that covers the muscles.
Parts of the soft palate:
- palatine curtain;
- palate-lingual (front) arc;
- palate-throat (back) arc.
Between the arches is located tonsil sinus, in which is palatine tonsil - accumulation of lymphoid tissue.
The muscles of the soft palate:
- muscle of tongue;
- muscle- lifter of palatal curtain;
- muscle- strainer of palatal curtain;
- palate-lingual muscle;
- palate-throat muscle. The last two muscles are located in the same-named brackets and put down palate curtain.
Lower wall of proper oral cavity - the bottom of oral cavity - formed by jaw-hyoid muscle, by front belly of two-belly muscle and by chin-hyoid muscle. Muscles are lined with mucous membrane inside.
From oral cavity food enters to the throat through the pharynx. Pharynx - a place of connection of oral cavity with throat. Pharynx is bounded from the bottom with the tongue, from top and from side - with soft palate.
Bodies of the oral cavity:
2. Salivary glands