The document describes the histological features of the esophagus and stomach. It discusses the general layers of the digestive tract wall and the specific layers and cell types found in the esophagus and different regions of the stomach. Key points include that the esophagus contains both skeletal and smooth muscle, while the stomach contains only smooth muscle. The stomach contains cardiac, gastric, and pyloric glands that differ in cell types and secretions.

1. DIGESTIVE SYSTEM - 2
ESOPHAGUS
AND
STOMACH

2. COMPONENTS
• Oral cavity
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Rectum
• Anal canal

3. ACCESSORY DIGESTIVE ORGANS
• Salivary glands
• Liver
• Pancreas

4. GENERAL PLAN OF DIGESTIVE SYSTEM
• The wall of digestive tract shows four distinct layers that represent
the basic histologic organization of the entire tract.
• Mucosa
• Submucosa
• Muscularis externa
• Serosa

5. MUCOSA
• Innermost layer of digestive tract
• It consists of :
• Epithelium
• Lamina propria - Underlying loose connective tissue
• Muscularis mucosae –
• Layer of smooth muscle
• Inner circular and outer longitudinal layer
• Outer boundary of mucosa

6. SUBMUCOSA
• Located underneath the mucosa
• It consists of dense irregular connective tissue containing:
• Numerous lymph and blood vessels
• Submucosal (Meissner) nerve plexus (postganglionic parasympathetic
nerve fibers)
• Meissner plexus controls motility of mucosa and secretory activities
of associated mucosal glands.

7. MUSCULARIS EXTERNA
• Thick, smooth muscle layer located below the submucosa
• Composed of :
• Inner circular smooth muscle layer
• Outer longitudinal smooth muscle layer
• Myenteric (Auerbach) nerve plexus – present between the two layers
• Contain post ganglionic parasympathetic nerve fibers controlling the
motility of smooth muscles of muscularis externa.

8. SEROSA
• It is the outermost layer of digestive tract and is continuous with the
mesentery and the lining of abdominal cavity.
• It is a serous membrane consisting of simple squamous epithelium
(Mesothelium) along with a thin layer of underlying loose connective
tissue.

9. ADVENTITIA
• When the viscera and part of digestive tract is not covered by
mesothelium, the outermost layer is formed by connective tissue
layer only called Adventitia.

10. ESOPHAGUS

11. ESOPHAGUS – PARTS
• Esophagus is divided into Thoracic and Abdominal part
• Histologic features of Abdominal part of esophagus varies in:
• Upper one third
• Middle one third
• Lower one third

12. ESOPHAGUS – HISTOLOGY FEATURES
• Mucosa: In empty state, mucosa shows numerous temporary
longitudinal folds.
i. Epithelium : Moist, stratified non keratinized epithelium
ii. Lamina propria: Connective tissue and glands
iii. Muscularis mucosa:
• Submucosa: Connective tissue and glands

14. ESOPHAGUS – HISTOLOGY FEATURES
• Muscularis externa: Contains both skeletal and smooth muscles
i. Upper 1/3rd part – Both the layers contain striated skeletal
muscles
ii. Middle 1/3rd part – Both the layers contain both striated skeletal
and smooth muscles
iii. Lower 1/3rd part – Both the layers contain smooth muscles

15. UPPER ESOPHAGUS – TRANSVERSE SECTION
 Mucosa: Numerous temporary longitudinal folds
• Epithelium – Stratified squamous non keratinized epithelium
• Lamina propria – Underlying thin layer of connective tissue
• Connective tissue papillae
• Smaller blood vessels
• Diffuse lymphatic tissue & solitary lymphatic nodule
• Mucous secreting glands – Esophageal Cardiac glands
• Excretory ducts
• Muscularis mucosae: Longitudinal layer of smooth muscle fibres

16. UPPER ESOPHAGUS – TRANSVERSE SECTION
• Submucosa: Wide layer of dense irregular connective tissue with:
• Adipose tissue
• Mucous acini of Esophageal glands proper
• Excretory ducts of mucous acini
• Numerous larger blood vessels
• Muscularis Externa: Two, well defined striated muscle layers with thin
layer of connective within them.
• Inner circular
• Outer longitudinal

17. ESOPHAGUS – MUCOUS GLANDS
LAMINA PROPRIA
• Esophageal Cardiac glands:
Simple branched tubular glands
• Secrete mucus, mucin, chlorides
and some biologically active
substances.
SUBMUCOSA
• Esophageal glands proper:
Compound tubulo-alveolar
glands
• Secrete mucus

19. UPPER ESOPHAGUS – TRANSVERSE SECTION
• Adventitia: Loose connective tissue layer which blends with that of
the surrounding structures.
• Adipose tissue
• Large blood vessels
• Nerve fibres

21. LOWER ESOPHAGUS – TRANSVERSE SECTION
 Mucosa: Numerous temporary longitudinal folds
• Epithelium – Stratified squamous non keratinized epithelium
• Lamina propria – Underlying thin layer of connective tissue
• Connective tissue papillae
• Smaller blood vessels
• Diffuse lymphatic tissue & solitary lymphatic nodule
• Mucous secreting glands – Esophageal Cardiac glands
• Excretory ducts
• Muscularis mucosae: Longitudinal layer of smooth muscle fibres

22. LOWER ESOPHAGUS – TRANSVERSE SECTION
• Submucosa: Wide layer of dense irregular connective tissue with:
• Adipose tissue
• Mucous acini of Esophageal glands proper
• Excretory ducts of mucous acini
• Numerous larger blood vessels
• Muscularis Externa: Two, well defined smooth muscle layers with thin
layer of connective within them.
• Inner circular
• Outer longitudinal

23. LOWER ESOPHAGUS – TRANSVERSE SECTION
• Serosa: Loose connective tissue layer lined by a simple squamous
layer (Mesothelium).
• Adipose tissue
• Large blood vessels
• Nerve fibers
• Upper 1/3rd of esophagus contains lesser amount of loose
connective tissue at all sites.

25. UPPER ESOPHAGUS :
LONGITUDINAL SECTION

26. UPPER ESOPHAGUS – LONGITUDINAL SECTION
 Mucosa: Numerous temporary longitudinal folds
• Epithelium – Stratified squamous non keratinized epithelium with
different layers
• Lamina propria – Underlying thin connective tissue with papillae,
blood vessels, Diffuse and aggregated lymphatic tissue, Esophageal
Cardiac glands and excretory ducts
• Muscularis mucosae: Longitudinally sectioned bundles of smooth
muscle fibers

27. UPPER ESOPHAGUS – LONGITUDINAL SECTION
• Submucosa: Wide layer of dense irregular connective tissue
containing adipose tissue, mucous acini of Esophageal glands
proper, excretory ducts of mucous acini and numerous larger blood
vessels.
• Muscularis Externa: Inner circular muscle layer is seen sectioned
transversely.

30. ESOPHAGEAL- GASTRIC
JUNCTION

32. ESOPHAGEAL – GASTRIC JUNCTION
ESOPHAGEAL FEATURES
• Mucosa: Non keratinized stratified
epithelium
• Lamina propria: Mucous cardiac
glands, ducts, lymphatic tissue
• Muscularis mucosae: Single layer of
longitudinal smooth muscle fibers
• Submucosa and Muscularis Externa:
Similar in structure and continuous
with that of stomach
GASTRIC FEATURES
• Mucosa: Simple columnar
epithelium
• Lamina propria: Filled with gastric
glands, gastric pits, lymphoid tissue.
• Muscularis mucosae: Double layer of
longitudinal smooth muscle fibers
• Submucosa and Muscularis Externa:
Similar in structure and continuous
with that of esophagus.

35. STOMACH

36. STOMACH – FEATURES
• Anatomically, stomach is divided
into:
• Cardia
• Fundus
• Body
• Pylorus
• Histologically, fundus and body
have a similar structure.

37. STOMACH – HISTOLOGIC FEATURES
• Histologically, stomach has three regions – Cardia, Fundus / Body and
Pylorus.
• Stomach wall exhibits four basic layers:
• Mucosa
• Submucosa
• Muscularis externa
• Serosa

38. MUCOSA
• Rugae: Numerous temporary folds
• Epithelium – Simple columnar epithelium (mucus secreting)
• Gastric pits – Tubular infoldings of the epithelium into lamina propria.
• Lamina propria – Present underneath the epithelium that fills spaces
between the gastric glands.
• Gastric glands- Deep to the pits, the mucous membrane is packed
with numerous gastric glands. Empty into the bottom of gastric pit.

41. MUCOSA
• Lamina propria:
• Scanty connective tissue
• Aggregations of lymphoid tissue
• Muscularis mucosae: Well developed, thin, smooth muscle layer
consisting of :
• Inner circular layer
• Outer longitudinal layer
• Additional outer circular layer may be present
• Thin strands are seen from Muscularis mucosae till epithelium.

43. STOMACH – GENERAL HISTOLOGIC FEATURES
• Submucosa: Dense, connective tissue with
• Lymph vessels and blood vessels
• Submucosal (Meissner’s) nerve plexus
• Muscularis Externa: Three layers of smooth muscle
• Inner oblique
• Middle circular
• Outer longitudinal
• Myenteric (Auerbach) nerve plexus

45. STOMACH – GENERAL HISTOLOGIC FEATURES
• Serosa: Thin, outer layer of connective tissue covered by simple
squamous epithelium (Mesothelium)
• Contains adipose cells

47. GASTRIC GLANDS
• They are of three types depending on their site of presence:
1. Cardiac glands
2. Main gastric glands
3. Pyloric glands

48. CARDIAC GLANDS
• Present in the Cardiac part of
stomach
• Simple tubular or compound
tubulo-alveolar
• Secrete mucus
• An occasional oxyntic or peptic cell
may be present

50. MAIN GASTRIC GLANDS
• Present in the Body and Fundus of
stomach
• Occupy 3/4th of the thickness of mucosa
• Simple or branched tubular type
• Open into the gastric pit
• Each gastric pit receives opening of
several glands
• Various types of cells present in the
epithelium lining the gastric glands are:
1. Chief cells
2. Oxyntic cells
3. Mucous neck cells
4. Endocrine cells
5. Stem cells

52. CHIEF CELL / PEPTIC /
ZYMOGEN CELL
• Numerous in Basal part of gland
• Basophilic, Cuboidal or low
columnar
• Luminal surface bears small,
irregular microvilli
• Prominent granules (pepsinogen) in
the apical part of their cytoplasm.
• Pepsin.
OXYNTIC CELL / PARIETAL
CELL
• Large, Ovoid / polyhedral
• Central large nucleus, Eosinophilic
• Present singly
• More numerous in Apical part of gland
• They lie against the basement
membrane bulge outwards into lamina
propria.
• Hcl, Intrinsic factor.

54. MUCOUS NECK CELL
• Mucous secreting cells, near upper
end of gland
• Large cells with clear cytoplasm
• Nucleus flattened displaced to the
base of cell
• Chemical nature of secreted
mucus is different
ENDOCRINE CELL /
ARGENTAFFIN CELL
• Contain membrane bound
neuro-secretory granules, stain
silver.
• Flattened cells, near Basal part
of gland
• Secrete gastrin, serotonin.

56. STEM CELL
• Undifferentiated cells
• Multiply to replace other cells

57. PYLORIC GLANDS
• Short glands present in pyloric part of
stomach
• Occupy deeper 1/3rd of the mucosa
• Simple or branched tubular glands, coiled.
• Lined by mucus secreting cells
• Occasionally oxyntic and argentaffin cells
are present.
• Gastrin

58. FEATURES OF EACH REGION OF STOMACH
CARDIA FUNDUS AND BODY PYLORUS
Presence of Cardiac
glands – mucus
Presence of Gastric
glands – hcl, pepsin,
etc.
Presence of Pyloric
glands – mucus
Shallow gastric pits Shallow gastric pits,
1/4th of mucosa
Deep gastric pits, 2/3rd
of mucosa
Change of epithelium
seen
Simple tall columnar Simple tall columnar
Circular muscle is thick-
pyloric sphincter

59. STOMACH - CARDIAC
• At low magnification, all four layers are seen.
• Mucosa –
• Epithelium – Simple columnar epithelium (mucus secreting). It is
sharply demarcated form that of esophagus.
• Shallow gastric pits – 1/4th of the mucosa
• Cardiac glands occupy the mucosa
• Cardiac glands are mucus secreting cells.

61. STOMACH – CARDIAC
• Lamina propria: seen
• Muscularis mucosae: Well developed, double layered smooth ms
fibers
• Submucosa: seen
• Muscularis externa: Well developed, three layered
• Serosa: seen

62. STOMACH – FUNDUS / BODY
• At low magnification, all four layers are seen.
• Mucosa:
• Epithelium – Simple tall columnar epithelium (mucus secreting)
• Shallow gastric pits – 1/4th of the mucosa
• Tubular gastric glands occupy – 3/4th of the thickness of mucosa
• In Deeper part- gastric glands branch, hence
• Each gland shows three regions: Isthmus, Neck and basal part.

63. STOMACH – FUNDUS / BODY
• Surface epithelial cells, Parietal cells, Mucous neck cells, Chief cells,
undifferentiated cells, entero-endocrine cells are seen.
• Lamina propria: seen distinctly
• Muscularis mucosae: Double layered smooth ms, strands seen.
• Submucosa: seen distinctly
• Muscularis externa: Well developed, three layered smooth ms fibers
• Serosa: seen distinctly

68. STOMACH – PYLORUS
• At low magnification, all four layers are seen.
• Mucosa:
• Epithelium – Simple tall columnar epithelium (mucus secreting)
• Deeper gastric pits – 2/3rd of the mucosa
• Short Pyloric glands (coiled) occupy – 1/3rd of the thickness of mucosa
• In Deeper part- gastric glands branch, hence
• Only one type of cell is found in epithelium of Pyloric glands - Tall
columnar, mucus secreting cell.

69. STOMACH – PYLORUS
• Entero-endocrine cells can be seen by special stains.
• Lamina propria: seen
• Muscularis mucosae: Well developed, double layered smooth ms
fibers
• Submucosa: seen
• Muscularis externa: Well developed, three layered
• Serosa: seen

71. SUMMARY