I. Structure and composition:
1, Lip: Lip is the outer boundary of the oral cavity, which consists of upper lip and lower lip. Lips are rich in nerve endings, sensitive to touch and temperature, and also play a role in protecting the mouth and the inside of the mouth.
2, teeth: teeth are located in the upper and lower jaws, mainly used for chewing food. Humans have different types of teeth, including incisors, canines and molars, which play different roles in food chewing and cutting.
3. Tongue: The tongue is located in the oral cavity and is an important part of the oral cavity. Tongue is not only used for chewing food, but also plays an important role in pronunciation. There are taste buds on the tongue, which can sense different tastes.
4, mandible: the mandible is divided into upper and lower jaws, and the teeth are located in the mandible. The movement of the chin helps to chew food and plays an important role in pronunciation.
Second, the function:
1, Eating and Digestion: The mouth is the entrance of food, and the food is broken down into small particles through the chewing of teeth and the mixing of saliva to prepare for the subsequent digestion.
2. Pronunciation and language: The structure and movement of the mouth are very important for pronunciation and language expression. The movements of the tongue and lips form different phonemes, which help to make sounds.
3, breathing: the mouth is also one of the channels for breathing. Although the nasal cavity is more suitable for filtering and moistening air, in some cases, the oral cavity can also be used as a breathing channel.
4. Emotions and expressions: Mouth expressions can convey rich emotions and information, such as smiling, smiling, opening your mouth and being surprised.
Three. Health and medicine:
1, oral hygiene: maintaining oral hygiene is very important to prevent oral problems such as tooth decay and gum disease. Regular brushing, flossing and regular physical examination are the keys to maintaining oral health.
2, tooth decay: tooth decay is a disease of teeth, usually caused by bacteria acting on food residue. Brushing your teeth regularly and limiting the intake of sugary foods can help prevent tooth decay.
3. Gum problems: Gum problems include gum bleeding and inflammation. Good oral hygiene and regular medical treatment help to prevent these problems.