1. Anatomy of the Digestive System
Organ System Cluster
Prepared by: Maria Michaela Valenzuela, PTRP

2. Reference
Seeley, R., Stephens, T., and Tate, P., Anatomy & Physiology. 8th ed. McGraw Hill Company Inc., (2008)
Snell, R., Clinical Anatomy by Regions. 8th ed. Lippincott Williams & Wilkins (2008)

3. Regional Division of the Abdomen
Used to facilitate location of the various organs of the abdominal cavity.

4. Abdominal quadrants: 4 – note umbilicus is used as reference
Abdominal regions:9 – note lines used:
*upper horizontal - transpyloric plane (L1)
*lower horizontal – intertubercular plane (L5)
*vertical – pass midpoint between ASIS & symph pubis

5. Organs of the Digestive System
Alimentary tract: main passage of food
Mouth
Pharynx
Esophagus
Stomach
Intestines
Accessory Organs
Teeth
Tongue
Salivary Glands
Liver
Pancreas

6. Histology of the Alimentary Canal
Mucosa
Innermost
Stratified squamous, simple columnar cells
Absorption
Submucosa
Connective tissue
Secretory function
Meissner’s plexus of nerve cells

7. Histology of the Alimentary Canal
Muscularis
Inner layer of circular smooth muscle
Outer layer of longitudinal smooth muscle
Myenteric Plexus of nerve cells
Motility function
Serosa
Outermost
Visceral peritoneum

9. Alimentary Tract: Mouth
Anteriorly: teeth
Posteriorly: fauces (throat)
Laterally: cheeks
Superiorly: palate
Inferiorly: muscular floor

10. Alimentary Tract: Mouth
Divisions
Anterior vestibule
Posterior oral cavity proper

11. Accessory Organ: Tongue
Muscular structure occupying floor of the oral cavity
Attached to the floor by frenulum
Intrinsic & extrinsic muscles

12. Vestibule, hard palate, soft palate, uvula, palatine tonsils, tongue, lingual frenulum

13. Accessory Organ: Teeth
32, distributed over dental arches
1 central incisor
1 lateral incisor
1 canine
2 pre molars
3 molars

15. Accessory Organs: Salivary Glands
Parotid
Anterior to the ear
Sublingual
Lie below mucous membrane of the oral cavity floor
Submandibular
Inferior border of the posterior half of the mandible

17. Alimentary Tract: Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Stratified squamous epthelium
 Transmit food

18. Alimentary Tract: Esophagus
Extends between the pharynx & stomach
25 cm long
Mediastinum, posterior to trachea, anterior to vertebrae
Sphincters
UES
LES

19. Alimentary Tract: Stomach
Divisions
Fundus
Body
Pyloric
Greater & Lesser Curvature
Sphincters
Cardiac

20. Fundus, body, pylorus, LES (cardiac sphicnter), , lesser curvature, greater curvature, pyloric sphicnter

21. Alimentary Tract: Stomach
Serosa – visceral peritoneum
Muscularis
Longitudinal
Circular
Oblique
Mucosal layer with rugae

22. Alimentary Tract: Small Intestine
6 m long
Where greatest amount of digestion & absorption take place
Divisions
Duodenum
Jejunum
Illeum

23. Alimentary Tract: Small Intestine
Duodenum
Short superior part
Duodenal papilla (minor & major) for entry of common bile duct
Mucosa & submucosa thrown into folds plica circulares
Microvilli

24. Alimentary Tract: Small Intestine
Jejunum & Illeum
Smaller in diameter
Jejunum: Major site of absorption (with duodenum)
Submucosal Lymphatic nodules: Peyer’s patches
Ileocecal junction with ileocecal valve

26. Accessory Organ: Liver
Largest organ
1.36 kg
® upper quadrant against the inferior surface of diaphragm
Lobes
(L) & ®
Caudate
quadrate

27. Accessory Organ: Gall Bladder
Sac-like structure on inferior surface of liver
8cm long, 4cm wide
3 tunics

29. Accessory Organ: Pancreas
Endocrine & Exocrine functions
2 types of cells
Acini
Islet
Parts
Head projecting on the duodenum
Body projecting towards the spleen
tail

31. Alimentary Tract: Large Intestine
From ileocecal junction to anus
Divisions
Cecum
Colon
Rectum
Anal canal

32. Alimentary Tract: Large Intestine
Cecum
Proximal
Attachment of appendix
Colon
Ascending colon & ® colic flexure
Transverse colon & left colic flexure
Descending colon

33. Alimentary Tract: Large Intestine
Colon
3 bands of Longitudinal muscle: teniae coli
Outpouching called haustra
Fatty tags: appendices epiploicae
Rectum & Anus
Muscular tube lined with Simple columnar epithelium
Internal & External Anal Spincter

34. Thank You for Listening!