anatomy of oesophagus

1. General anatomy of
oesophagus and stomach
BSc. Clinicals
L.H. Tembo

2. Objectives
• General gross structure of esophagus and stomach
• General histological structure of esophagus and stomach
• Innervation of esophagus and stomach
• Arterial supply of the esophagus and stomach

3. Digestive System
• Consist of
• Digestive tract – a tube extending
from mouth to anus
• Associated organs – primarily glands
• Upper digestive system
• Mouth, esophagus, stomach
• Lower digestive system
• Small intestines, large intestines, anus

4. General structure of the Digestive system
• Histologically consist of 4 layers
• Mucosa
• Submucosa
• Muscularis
• Adventia/Serosa

5. Mucosa
• Innermost layer has 3 layers
• Mucous epithelium
• Moist stratified squamous epithelium
• Mouth, oropharynx, esophagus and anal canal
• Simple columnar epithelium
• Remainder of digestive tract
• Invaginate to form
Glands ( Extend into Lamina Propria –
Mucosa Glands or Submucosa –
Submucosa Glands)
Ducts

6. Mucosa
• Lamina Popria
• Loose CT
• Diffuse lymphatic tissue+ lymphatic
nodules + immunocomponents cells
(lymphyocytes, plasma cells,
macrophages)
• In small and large intestines is a relevant
site for immune response
• Muscularis mucosae
• Outer thin smooth muscle layer

7. Submucosa
• Thick/dense CT
• Has nerves, blood vessels and small
glands that lie beneath mucosa
• There is a network of nerves called
Submucosa plexus
• Nerve fibers into mucosa and muscularis +
ganglion cells = Meissner’s plexus
• Submucosal glands – Found in
eosophagus and duodenum

8. Muscularis externa
Two smooth muscle layers
1. Inner circular - reduces lumen
2. Outer longitudinal – shortens the tube
Exception
Upper esophagus and anal sphincter have skeletal muscles
Esophagus muscularis layer
(i) Striated – upper 1/3 – cont. of pharynx muscle
- innervated by somatic motor neurons of the vagus nerve
(ii) Striated+smooth - middle 1/3
(iii) Smooth - distal 1/3 –innervated by visceral motor neurons of
the vagus
Also contain Myenteric Nerve Plexus (Auerbach’s plexus)
- for peristaltic activity

9. Adventia/Serosa
• Several layers of CT
• Continuous with adjacent CT
• Serosa is visceral peritoneum covered
by mesothelium supported by a thin a
CT

10. Microvasculature of Digestive System
• Neurovascular structures reach the GIT through the supporting
mesentery or surrounding tissue
• After entering the walls of stomach, arteries organize into 3 arterial
network
• Subserosa plexus
• Intramuscular plexus
• Submucosal plexus
• In mucosa, arterioles from submucosal plexus supply the bed of
fenestrated capillaries around the gastric gland
• Also anastomose laterally
• Venules collecting blood descend from mucosa into the submucosa as
veins
• Leave the digestive tube through mesentery then through splenic and
superior mesenteric veins to portal vein

12. Nerve Supply
• GIT innervated by ANS
• ANS consist of 2 parts
• Extrinsic Component
• Sympathetic - derived
from thoracic and lumbar
spinal cord
• Parasympathetic –
derived from vagal dorsal
motor nucleus of the
medulla oblangata

13. Nerve Supply
• Intrinsic/Enteric Component
• Represented by 2 distinct
interconnected neuronal circuit
• Formed by sensory and motor
neurons lined by interneurons
• 1. Submucosal plexus of Meissner
present in submucosa
• 2. Myenteric plexus of Auebach –
located in the muscularis between
circular and longitudinal muscles
• Help to respond to local stimuli and
input from extrinsic nerves of the
ANS

14. General structure of the esophagus and GIT
• Hollow muscular tube
- 25 cm long, 2 cm
diameter
• Extent: pharynx –
stomach
• Wall made of 4
principal layers
• The mucosa
• Submucosa
• Muscularis
• Serosa/adventia

16. General
• In stomach and small intestines, both mucosa and submucosa extend
into the lumen as folds called Rugae and plicae respectively
• In other instances the mucosa alone extend into the lumen as fingers
or villi
• Mucosa glands they increase the secretory capacity
• Villi increase the absorptive capacity of the digestive tube

17. The esophagus
Mucosa
• Most varied along the GIT
1. Lining Epithelium
Non –keratinized stratified squamous epithelium
2. Lamina propria
Vascularized loose CT
3. Muscularis mucosa
Not present in the upper portion of the esophagus
but become organized near the stomach
Thin layer of smooth muscles (thick
longitudinal smooth muscle)

18. The esophagus cont….
b. Submucosa
• Consists of :
• Dense irregular CT
• Large blood and lymphatic vessels
• Diffuse lymphatic tissue and nodules –upper + lower
parts
• Nerve fibers into mucosa and muscularis + ganglion
cells = Meissner’s plexus
• Submucosal glands – lower and upper parts

19. The esophagus cont….
c. The muscularis externa
• Two muscle layers;
1. inner circular
2. outer longitudinal
• Differs from the rest of digestive
tract;
(i) striated – upper 1/3 – cont. of
pharynx muscle
- innervated by somatic motor
neurons of the vagus nerve
(ii) Striated+smooth - middle 1/3
(iii) Smooth - distal 1/3 –innervated by
visceral motor neurons of the vagus

20. c. The muscularis externa
• Contains myenteric nerve plexus (Auerbach’s plexus)
- for peristaltic activity
d. The serosa/adventitia
• Outer layer – adventitia
• Distal 1 to 2 cm - serosa
The esophagus cont….

21. Esophagus
• Constrictions
 Upper esophageal sphincter -
cricopharyngeus muscle
• Gastroesophageal or cardiac
opening - Opening of esophagus
into the stomach (located near the
heart)
• Lower Esophageal Sphincter
(cardiac sphincter) surrounds
cardiac opening.
• Where it passes diaphragm
• Cardiac sphincter is a physiologic
constrictor only and cannot be seen
anatomically.

22. Esophagus
• Esophagogastric
junction
• Z-line - change of
esophageal to gastric
mucosa

23. Anatomy of the Stomach
• The opening between the stomach
and the small intestine is the pyloric
opening
• Surrounded by a relatively thick ring
of smooth muscle
• Pyloric sphincter.

25. Anatomy of the Stomach
• Location - LUQ of abdomen
• Regions
 Cardiac
 Region of the stomach around the
cardiac opening is Cardiac region
 Fundus
 Fundus is superior to the cardiac
opening.
 Body
 Largest part of the stomach is the
body
 Pyloric
 Narrow part joining small intestine
• Lesser curvature
• Lesser omentum
• Greater curvature
• Greater omentum

26. Divided histologically into 3 regions:
Summary
1. Cardiac region – contains
cardiac glands
2. Fundic region – contains
fundic glands
3. Pyloric region - contains
pyloric glands

27. Histology of the Stomach
• Serosa, or visceral peritoneum, is the outermost
layer of the stomach.
• Consists of an inner layer of CT and an outer layer of
simple squamous epithelium.
• Muscularis
• Has three layers
• Outer Longitudinal layer,
• Middle Circular layer
• Inner Oblique layer
• In some areas of the stomach, such as in the
fundus, the three layers blend with one another
and cannot be separated.
• Submucosa and the mucosa, have large folds
called rugae (when the stomach is empty)

28. Histology of the Stomach
• Stomach lined with
simple columnar
epithelium.
• Epithelium forms
numerous tube like
gastric pits
• Openings for the
Gastric Glands
• The epithelial cells
of the stomach are
of five types.
Mucosa
Submucosa
Muscularis
Serosa
Gastric Pit
Surface mucous cells,
Produce mucus
On the surface and lines the
gastric pit.
Mucous neck cells,
produce mucus
Parietal (oxyntic) cells, produce
hydrochloric acid and intrinsic
factor
Chief (zymogenic) cells, which
produce pepsinogen;
Endocrine cells, which produce
regulatory hormones.
Gastric Gland

29. Epithelial cell renewal in the stomach
• Mucous neck cells are located near the openings of the glands
• Parietal, chief, and endocrine cells are interspersed in the deeper parts of the
glands.
1. Surface mucus cells – renew approx. 3-5 days from isthmus
2. Cells of fundic glands – have relatively longer lifespan:
(i) Parietal cells – 150-200 days
(ii) Chief and enteroendocrine cells – 60-90 days
(iii) mucus neck cells – 6 days

31. Gastric submucosa
• Composed of:
1. Dense CT +adipose tissue
2. Blood vessels
3. Nerve fibers and ganglions (submucosal (Meissner’s) plexus
Gastric serosa
• Continuous with peritoneum of :
1. abdominal cavity
2. liver

32. Relations of the stomach
• Covered by peritoneum
• Anterior
• Diaphragm
• Liver - left lobe
• Abdominal wall
• Posterior
• Omental bursa
• Pancreas

33. Stomach bed
• Superior to inferior
• Left dome of
diaphragm
• Spleen
• Left kidney &
suprarenal gland
• Splenic artery
• Pancreas
• Transverse
mesocolon & colon

38. NERVE SUPPLY AND LYMPH DRANAIGE
• Parasympathetic
nerve supply
• Ant & post vagal
trunks - ant & post
gastric nerves
• Sympathetic from T6-
T9 passes to celiac
plexus through
• Greater splanchnic
nerves
• Lymph

39. Mesentery Membrane
• Other abdominal organs lie against the
abdominal wall
• No mesenteries - Retroperitoneal
• Examples
• Duodenum,
• Pancreas,
• Ascending colon,
• Descending colon
• Rectum
• Kidneys
• Adrenal glands
• Urinary
• Bladder

40. Small Intestine
• Divided into:
• Duodenum
• Jejunum
• Ileum.
• Wall of the small intestine consists:
• External serosa,
• Muscularis (longitudinal and circular)
• Submucosa
• Mucosa - simple columnar epithelium.
• Has large surface area
• Plicae circulares (valves of Kerkering)
• Permanent circular folds of mucosa and submucosa
• From deodenum to half way to ileum
• Villi
• Microvilli (on apical surface of intestinal cells)
• Absorptive, goblet, and endocrine cells are in. Intestinal
glands
• Duodenal glands produce mucus

41. Small intestines
• Duodenum
• Has Brunner’s glands
• Secrete alkaline secretions
• Broad and short villi (leaflike)
• Collect bile and pancreatic secretions
• Incomplete serosa
• Extensive adventia

42. Small intestines
• Jujenum
• Lumen slightly larger than
ileum
• No Brunner’s glands
• More plicae circulare
• Long fingerlike villi
• Few Peyer’s patches
• Deeper red with greater
vascularity
• Ileum
• Have shorter straight
arteries than jejunum
• Has abundant lymph
nodules - Peyer’s patches

44. Anatomy of the Large Intestine
• Cecum forms a blind sac at the junction of the small and
large intestines.
• The vermiform appendix is a blind tube off the cecum.
• Ascending colon - cecum superiorly to right colic flexure
• Transverse colon - right to left colic flexure
• Descending colon - extends inferiorly to join the sigmoid
colon.
• Sigmoid colon - an S-shaped tube that ends at the rectum.
• Longitudinal smooth muscles - arranged into bands called
Teniae coli
• Contraction produce pouches called Haustra
• Rectum is a straight tube that ends at the anus
• Internal anal sphincter (smooth muscle) and an External
anal sphincter (skeletal muscle) surround the anal canal.

46. Large Intestines
• No plicae circulares
• No villi
• Mucosa lining - Simple columnar epithelia
• Numerous straight tubular glands
(glandular epithelia)
• Goblet cells
• Muscularis has taeniae coli

48. Thanks
GOOD DAY

49. 1. The gastric mucosa (epithelium, lamina propria, muscularis
mucosae)
a. The gastric epithelium
• The surface and gastric pits are lined
by simple columnal epithelium
• Columnal cells are called surface
mucus cells – have apical cup of
mucinogen granules – secret visible
insoluble mucus
• Surface lining can absorb: water salts,
lipid soluble drugs, alcohol, certain
drugs e.g. aspirin