composition Digestive tube Mouth Pharynx Esophagus Stomach Small

组成composition 消化管Digestive tube • 口腔 Mouth • 咽 Pharynx • 食管 Esophagus • 胃 Stomach • 小肠Small intestine Superior digestive tube 上消化道 十二指肠 Duodenum 空肠 Jejunum 回肠 Ileum Inferior digestive tube 下消化道 • 大肠Large intestine 消化腺Digestive glands • • • 大唾液腺Major salivary glands 肝Liver 胰Pancreas Function: ingestion, digestion, absorption, egesting

Mouth Major salivary glands Pharynx Esophagus Stomach Liver Pancreas Duodenum Large intestine Ileum Jejunum

口腔 Oral Cavity Consists of two parts vestibule : between cheeks and lip and teeth • 固有口腔Oral cavity proper: within arch of teeth • 口腔前庭Oral Boundaries of oral cavity proper • • Anterior and lateral: gum and teeth Posterior: isthmus of fauces Roof: palate Floor: tongue, muscles and mucous membrane Oral vestibule leads, by the space behind the molar teeth, into the oral cavity proper

腭Palate Two parts • Hard palate: anterior 2/3, formed by the maxilla and palatine bone • Soft palate: posterior 1/3 – – 腭帆Velum palatinum 腭垂 Uvula 腭舌弓Palatoglossal arch 腭咽弓Palatopharyngeal arch 咽峡Isthmus of fauces formed by posterior border of velum palatinum, both side of palatoglossal arches, and root of tongue.

牙Teeth General features • Two sets: – 乳牙Deciduous – 恒牙Permanent • Classification: – – 切牙Incisors 尖牙Canine 前磨牙Premolars 磨牙Molars

Deciduous teeth: are 20 in number • Ten teeth in each mandibular and maxillary arch • Central incisor中切牙, lateral incisor侧切牙, canine尖牙, first molar第一磨牙 and second molar第二磨牙 in each quadrant Upper jaw Lower jaw Ⅰ in. Ⅱ Ⅲ Ⅳ Ⅴ total 20 in. can. mol. • Eruption: stars at about 6 mouth of age and continues to beginning of 3 rd year • Shedding: occurs between 6 th and 12 th years with replacement by permanent teeth

Permanent teeth (adult): are 32 in number • Sixteen in each mandibular and maxillary arch • Two incisors, one canine, two premolars, and three molars in each quadrant Upper jaw 1 2 3 4 5 6 7 8 total 32 Lower jaw • First permanent molar－ appears at about 6 years • Third molars (wisdom teeth)－many erupt at any time after 12 years of age or not at all (impaction).

General description • Each tooth consists of 3 parts: – 牙冠Crown – 牙颈Neck – 牙根Root • 牙腔Dental cavity－contains connective tissue, blood vessels and nerves, and is continuous with the periodontal tissue through the root canal and apical foramen.

Calcified tissues 牙组织 • 牙质Dentine－ is a yellowish white tissue, that forms the bulk of tooth. • 釉质Enamel －is a hard, brittle white tissue that covers the crown of the tooth • 牙骨质Cement －is an unusual form of bone that covers the root of the tooth • 牙髓 dental pulp 牙周组织Periodontal tissue • 牙周膜Periodontal membrane • 牙槽骨Alveolar bone • 牙龈Gum

舌Tongue －muscular organ Two parts: divided two parts by vshaped界沟terminal sulcus • Body of tongue 舌体－anterior 2/3， apex of tongue 舌尖－free rounded tip • Root of tongue 舌根－ posterior 1/3 At the apex of terminal sulcus is a small median pit, the foramen cecum of tongue 舌盲孔

Lingual mucous membrane • Papillae of tongue 舌乳头 – – Filiform papillae 丝状乳头 fungiform papillae 菌状乳头 foliate papillae 叶状乳头 vallate papillae 轮廓乳头 • Lingual tonsil 舌扁桃体 －masses of submucosal tissue on the root of tongue contain taste buds lymphoid

Inferior surface of tongue • Frenulum of tongue 舌系带 －a midline fold of mucous membrane connecting tongue to floor of mouth • Sublingual caruncle 舌下阜 －small elevation • Sublingual fold 舌下襞

Muscles of tongue 舌肌 • Intrinsic muscles of tongue – Involved in changing shape of tongue – Include longitudinal, transverse and vertical muscles of tongue • Extrinsic muscles of tongue – Genioglossus 颏舌肌 • Arises from mental spine of mandible and inserts into either side of midline of tongue • Action: acting together draw tongue forward and downward (depresses and protrudes tongue ); acting along making apex of tongue to opposite side Hyoglossus 舌骨舌肌 Tyloglossus 茎突舌肌 – – – Involved in determining shape and position of tongue

大唾液腺Major salivary glands 腮腺Parotid gland • Superficial part: triangular in shape, lies below and in front of the external acoustic meatus, and partially covers the masseter. • Deep part: lies deep to medial pterygoid. • Parotid duct: arises front anterior border of gland, runs over the masseter a finger’s breadth below the zygomatic arch to pierce the buccinator and opens into the mouth cavity, opposite the upper second molar tooth

Submandibular gland 下颌下腺 • Position: lies in submandibular triangle, between anterior and posterior bellies of digastric • Duct opens on to sublingual caruncle Sublingual gland 舌下腺 • position: situated beneath the mucous membrane of the sublingual fold • Ducts – Major sublingual duct－ opens onto the sublingual caruncle – Minor sublingual ducts－ open onto the sublingual fold

The Pharynx 咽 General features • A –fibromuscular tube, part of digestive and respiratory systens • Extends from base of skull to the inferior border of cricoid cartilage (lower border of C 6 level) • Three segments

Nasopharynx 鼻咽 － posterior to nasal cavities • Extends from the base of skull to level of soft palate, below • Features – Pharyngeal opening of auditory tube 咽鼓管咽口Tubal torus咽鼓管圆枕 – Pharyngeal recess 咽隐窝 – Tubal tonsil 咽鼓管扁桃体 – Pharyngeal tonsil 咽扁桃体 Oropharynx 口咽 － posterior to oral cavity • Lies below soft palate, extends to upper border of epiglottis

Oropharynx 口咽 • Features – Median glossoepiglottic fold 舌会厌正中襞 – Epiglottic vallecula 会厌谷 – Palatine tonsil 腭扁桃体－ lies within tonsillar fossa Lymphatic ring－consists of pharyngeal tonsil, tubal tonsil, palatine tonsil, and lingual tonsil, forming a circular band of lymphoid tissue at oropharyngeal isthmus

Laryngopharynx 喉咽－posterior to larynx • Extends from upper border of epiglottis to the level of lower border of C 6 • Piriform recess梨状隐窝－a deep depression on each side of aperture of larynx, common site for lodgement of foreign bodies (for example, fish bones)

The Esophagus 食管 General features －a muscular tuber about 25 cm long, connecting the pharynx at level of C 6 vertebra, passes through the diaphragm at level of T 10 vertebra and after 1~2 cm enters the stomach Division: • Cervical part • Thoracic part • Abdominal part

Three constrictions • At its beginning, 15 cm from incisors, lies at level of C 6, is the narrowest part of the esophagus • Where it is crossed by left main bronchus, 25 cm from incisors, lies at level of intervertebral disc between T 4 and T 5. • Where it passes through the esophageal hiatus of diaphragm, 40 cm from incisors, at level of T 10