Chapter 5 The Alimentary System Part II Splanchnology Chapter 5 The Alimentary System

Ⅰ. General Description: * Constituents: 2 parts Alimentary canal: the mouth, the pharynx, the esophagus, the stomach, the small intestines: the duodenum, the jejunum, the ileum the large intestines: the cecum and appendix, the colon, the rectum, the anal canal Digestive glands: the salivary glands: the parotid gland the submandibular gland the sublingual gland the liver, the pancreas

* Functions: ingest foods, secrete enzymes, absorb nutrients eliminate unused residues

Ⅱ.The Mouth: * 2 parts: oral vestibular, oral cavity proper. * walls: oral lips, cheeks, palate, tongue. isthmus of fauces * contents: teeth, tongue. * palate: hart palate soft palate palatine velum palatoglossal arch palatopharyngeal arch palatine tonsil * isthmus of fauces: uvula free margin of palatine velum root of tongue.

* The teeth The structure: crown dentine deciduous teeth permanent teeth The structure: crown root neck of teeth dentine enamel cement periodontal membrane dental cavity, root canal apical foramen dental pulp

deciduous teeth: 20 2 pairs of incisors 1 pair of canine tooth 2 pairs of molars permanent teeth: 28-32 2 pairs of premolars 3 pairs of molars (wisdom tooth)

The tongue 3 parts--- root, apex and body 2 surfaces---dorsum and inferior surface Dorsum: V-shaped terminal sulcus 4 kinds of papillae---- Filiform papillae Fungiform papillae Foliate papillae Vallate papillae lingual tonsil

mucosa, muscles of the tongue Inferior surface of tongue: the Frenulum of tongue the Sublingual caruncle the Sublingual folds Structures: mucosa, muscles of the tongue

Ⅲ. The pharynx: Position: in front of the 1~6th cervical vertebrae Parts: Nasopharynx Oropharynx Laryngopharynx Features and structures: nasal part---- pharyngeal opening of auditory tube tubal torus pharyngeal recess oral part--- palatine tonsil, tubal tonsil laryngeal part---piriform recess

Communication of pharynx: anteriorly: ---choanae---nasal cavity ---isthmus of fauces---oral cavity ---aperture of larynx---laryngeal cavity inferiorly: ---esophagus Laterally:---pharyngeal opening of auditory tube---tympanic cavity

Ⅳ.The Esophagus: 3 parts: cervical, thoracic and abdominal parts 3 constrictions: 1st---at its commencement, 15cm from the incisor teeth 2nd---where is crossed by the left principal bronchus anteriorly, 25cm from the incisor teeth 3rd---where it passes through the diaphragm, 40cm from the incisor teeth Structures: upper part: skeleton m. middle part: skeleton m.and smooth m. lower part: smooth m. position

The Salivary glands: The Parotid gland The Sublingual gland The Submandibular gland The Name, Positions, Opening of its ducts

Ⅴ.The stomach : The shape and parts 2 openings: cardia, pylorus 2 surfaces: anterior and posterior 2 curvatures: greater curvature lesser curvature angular incisure 4 parts: the cardiac part the fundus of stomach the body of stomach the pyloric part pyloric antrum pyloric canal

The position and relations --- the position: Its between the end of the esophagus and the beginning of the small intestine. It lies in the epigastric, umbilical and left hypochondriac regions of abdomen. cardiac orifice– at left side of 11th thoracic vertebra pyloric orifice– at right side of 1st lumbar vertebra

--- the relations: diaphragm left pleura the base of the left lung anteriorly--- left costal margin diaphragm left pleura the base of the left lung the left pleural cavity the pericardium left and quadrate lobes of the liver the anterior abdominal wall transverse colon

posteriorly--- the diaphragm the spleen the left suprarenal gland the upper part of the left kidney the splenic artery the left colic flexure the anterior surface of the pancreas the upper layer of the transverse mesocolon “ stomach bed ” omental bursa

The structures of the wall of stomach: 4 layers --- mucosa: mucous folds longitudinal mucous folds pyloric valve --- submucosa --- muscular layers: inner oblique layer intermediate circular layer pyloric sphincter outer longitudinal layer --- serous membrane

Ⅵ.The duodenum C-shaped 4 parts---superior part Structure--- descending part horizontal part ascending part Structure--- Descending part has longitudinal fold major duodenal papilla Position and relationshap--- It encloses the head of the pancreas; A retroperitoneal organ; Most part of it attached the posterior abdominal wall.

Ⅶ. Jejunum and Ileum: Upper 2/5 Lower 3/5 Wider in diameter and wall is thicker; Thiner in diameter and wallis thinner Color is redder and has more vascular Color is not redder than jejunum and has lesser vascular The circular mucosal folds are larger and more The circular mucosal folds are shorter and few Only solitary lymphatic follicles Solitary and aggregated lymphatic follicles

Ⅷ. Large intestine: Parts--- colon cecum rectum anal canal structures --- except rectum anal canal and appendix 3 colic bands haustra of colon epiploic appendices

The cecum and vermiform appendix : position: in the right iliac fossa, above the lateral half of the inguinal ligament and below the ileocecal valves. structure: ileocecal valves opening of the vermiform appendix

spings from the posteromedial wall of the cecum. Vermiform: shape: worm shaped tube, 2—20 cm in length, about 8.3cm in average Position: right iliac or inguinal region , spings from the posteromedial wall of the cecum. common positions of the tip: retrocecally, inferior to the cecum, behind or front of ileum, into the lesser pelvis Surface projection of the root of vermiform appendix--- McBurney’s point

McBurney’s point At the junction of the meddle and lateral thirds of a line that joints the right anterior superior iliac spine and the umbilicus.

Colon: 4 parts---- transverse colon descending colon sigmoid colon ascending colon transverse colon descending colon sigmoid colon

position--- It lies in the posterior part of less pelvis, The rectum: position--- It lies in the posterior part of less pelvis, anterior to the sacrum and coccyx. shape--- 2 flexures: Sacral flexure Perineal flexure Ampulla of rectum structures--- 3 transverse folds of rectum

mucous membrane--- anal columns The Anal Canal: position: structures: anal valves anal sinuses dentate line anal pecten (hemorrhoidal ring ) white line submucosa--- muscular layer--- sphincter ani internus sphincter ani externus