Digestive System Anatomy Digestive tract Alimentary tract or canal Gastrointestinal (GI) tract Accessory organs Primarily glands Liver, gallbladder, pancreas, salivary glands Regions Mouth or oral cavity Pharynx Esophagus Stomach Small intestine Large intestine Anus

ORAL CAVITY

ORAL CAVITY دهليز حفره دهان: كام سخت و كام نرم ، زبان و پرده‌هاي مخاطي غدد بزاقي : سه زوج لب‌ها گونه‌ها لثه‌ها Gums , Gingiva دندان‌ها Teeth

Tooth Structure Figure 23.11

Classification of Teeth Incisors (2) Canines (1) Premolars (2) Molars (3) Slide 14.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Teeth Composition Dental caries Wisdom teeth – 3rd molars Dentin – primary substance in tooth Enamel – covers crown Cementum – covers root Dental caries Wisdom teeth – 3rd molars formation of erythrocytes

Tongue Figure 23.8

Palate and Palatine Tonsils Hard palate Soft palate: Palatine tonsils:

Tonsils the pharyngeal tonsil= adenoids when enlarged, is in the midline on the roof of the nasopharynx the palatine tonsils are on each side of the oropharynx between the palatoglossal and palatopharyngeal arches just posterior to the oropharyngeal isthmus; (The palatine tonsils are visible through the open mouth of a patient when the tongue is depressed.)

Salivary Glands Parotid Submandibular Sublingual

Salivary Glands Figure 23.9a

Anatomy of The pharynx Site Seen from behind Midline of the neck From skull base to esophagus In front of upper 6 Cervical vertebra Behind : The Nose The Mouth The larynx

Anatomy of The pharynx Shape Irregular Fibromuscular tube lined by mucous membrane Length: 15 cm

Anatomy of The pharynx Structure The wall is formed of 4 layers 1-Mucous membrane 2- pharyngeal aponeurosis 3-muscle layer 4-Bucco-pharyngeal fascia Formed of 3 muscles, superior middle and inferior constrictor muscles Loose connective tissue which contains lymphoid tissue that aggregates in some areas forming tonsils (Waldayer’s ring) Stratified squamous epithelium except the nasopharynx, it is pseudo-stratified with goblet cells A thin coat of connective tissue

What is Waldeyer’s ring? The lymphoid tissue in the pharyngeal aponeurosis aggregates in some areas forming tonsils: 1-one nasopharyngeal tonsil 2- two palatine tonsils 3- two lingual tonsils

Anatomy of the pharynx Compartments Seen from behind Nasopharynx Oropharynx Laryngopharynx (Hypopharynx)

Seen from lateral Nasopharynx Oropharynx Laryngopharynx (Hypopharynx)

Nasopharynx -Behind the nasal cavity -Extends from skull Base superiorly to the soft palate inferiorly Communicates inferiorly with the oropharynx through the velo-pharyngeal sphincter The nasopharyngeal tonsil lies in the roof The pharyngeal opening of ET lies in the lateral wall

Nasopharynx

Oropharynx Behind the oral cavity (in front of 2nd&3rd Cervical vertebra) From the soft palate superiorly to tip of epiglottis inferiorly Communicates: Anteriorly with the oral cavity Superiorly with the nasopharynx Inferiorly with the hypopharynx The paatine tonsils lie laterally between the anterior and posterior pilars

The posterior pillar formed The tonsils lie between the The anterior pillar formed by palatoglossus muscle The posterior pillar formed By palatopharyngeus m The tonsils lie between the Two pillars

Oropharynx: palatoglossal folds (arches) palatopharyngeal folds palatine tonsils

Hypopharynx Behind the Larynx (in front of 3rd to 6th Cervical vertebra) From the tip of epiglottis superiorly to the lower border of cricoid cartilage Inferiorly Communicates: Anteriorly with the Larynx Superiorly with the oropharynx Inferiorly with the esophagus

The hypopharynx does not only lie behind the larynx BUT also Seen from behind The hypopharynx does not only lie behind the larynx BUT also Projects laterally on each side of the larynx So it is formed of : Postcricoid region ( behind the larynx) Two pyriform fossa (on each side of the larynx Cross section

The Esophagus

Peritoneum and Peritoneal Cavity Mesentery Retroperitoneal organs Peritoneal organs (intraperitoneal) –

General arrangement of abdominal GI organs Peritoneum Parietal peritoneum Visceral peritoneum Peritoneal cavity Intraperitoneal organs Retroperitoneal organs

General arrangement of abdominal GI organs Mesentaries Double layered folds of peritoneum Greater omentum Lesser omentum Mesentery proper Suspends small intestine from posterior wall of abdomen Mesocolon Suspends large intestine Peritoneal ligament Peritoneum that attaches one organ to another

Peritoneum and Peritoneal Cavity Figure 23.5a

Peritoneum and Peritoneal Cavity Figure 23.5b

Stomach Anatomy Figure 14.4a

Stomach Anatomy Regions of the stomach Cardiac region Fundus Body Pylorus – terminal end Food empties into the small intestine at the pyloric sphincter

Subdivisions of the Small Intestine Duodenum

The Duodenum and Related Organs Figure 22.16

Jejunum Ileum

Large Intestine Larger in diameter, but shorter than the small intestine Has subdivisions

Large Intestine Figure 14.8

Structures of the Large Intestine Colon Ascending Transverse Descending Sigmoid (S-shaped) Rectum Anus – external body opening

Liver - Anatomy