The document discusses the embryology, anatomy, histology, and pathology of the gastrointestinal system. It provides details on: 1) The development of the foregut, midgut, and hindgut during embryology and the rotation of the midgut loop. 2) The anatomy of the small intestine including the four parts of the duodenum, and divisions of the jejunum and ileum. 3) Histology of the four layers of the small intestine - mucosa, submucosa, muscularis, and serosa. 4) Causes, pathophysiology, clinical manifestations, diagnosis and treatment of small bowel obstruction and ileus.

1. 
‫خدا‬ ‫نام‬ ‫به‬

3. 
Embryology
Anatomy
Histology
Pathology
Contents:

4. 
General Outline of GI organ development
embrylogy
Foregut Midgut Hindgut
· Lungs · 2nd part of
duodenum
· Last 1/3 of
transverse colon
· Stomach · Jejunum · Descending
colon
· Part of
duodenum
· Ileum · Rectum
· Gall bladder · Ascending
Colon
· Liver · 2/3 of
transverse colon
· Pancreas

5. 
Development of the Midgut
Primary intestinalloop Physiological
umbilical hernia
Reduction of the
hernia

6. 
•
The midgut forms a U-shaped loop that herniates into
the umbilical cord during the 6th weeks of gestation
•
While in the umbilical cord, the midgut loop rotates 90
degrees
•
During the 10th week of gestation, the midgut loop
returns to the abdomen, rotating an additional 180
degrees
The Midgut Rotation

7. 
The Midgut Rotation

8. 
The small intestine extends from the pylorus of the
stomach to the iloececal junction
It is divided
duodenum
Jejunum
ileum.
Anatomy

9. 
The duodenum is the most proximal portion of the
small intestine
It runs from the pylorus to the duodenojejunal
junction.
Anatomically, we can divide the duodenum into
four parts; superior, descending, inferior and
ascending
duodenum

10. 
Parts of duodenum

11. 
The superior section of the duodenum (sometimes
called ‘the cap’) is 5cm in length
Duodenal ulcers are most likely to occur in this part of
the duodenum.
Superior (L1)

12. 
the descending duodenum is marked by the major
duodenal papilla - an opening for bile and pancreatic
secretions to enter. The duct responsible carrying these
secretions is known as the ampulla of vater or
hepatopancreatic ampulla.
Descending (L1-L3)

13. 
The inferior section travels laterally to the left,
crossing over the inferior vena cava and aorta. It is
located inferiorly to the pancreas, and posteriorly to
the superior mesenteric artery and vein.
Inferior (L3)

14. 
After the duodenum crosses the aorta, it ascends and
curves anteriorly to join the jejunum at a sharp turn
known as the duodenojunal flexure
Ascending (L3-L2)

15. 
Jejunum and Ileum

16. 
Jejunum and Ileum

17. 
Foregut ( which is supplied by
celiac artery)
Midgut (which is supplied by
superior mesenteric artery)
Hingut ( which is supplied by
inferior mesenteric artery)
arterial supply

18. 
Duodenum
The initial part of the duodenum is supplied by
gastroduodenal artery, a branch of the celiac
trunk
Distal to the major duodenal papilla, the inferior
pancreaticodudenal artery supplies the
duodenum. It is a branch of the branch of superior
mesenteric artery.
arterial supply

19. 
Jejunum and Ileum
The arterial supply to the jejunoileum is from the
superior mesenteric artery
The superior mesenteric artery arises from the aorta at
the level of the L1 vertebrae, immediately inferior to the
celiac trunk. It moves in between layers of mesentary,
splitting into approximately 20 branches
arterial supply

20. 
The venous drainage is performed by the superior
mesenteric vein. It unites with the splenic vein at
the neck of the pancreas to form the hepatic portal
vein.
venous drainage

21. 
4 layers
1 Mucosa
Muscularismucosa: thin, separate from mucosa:
submucosa
Lamina propria: connective tissue, immune function
Epithelial layer: covers vili and crypts
Goblet cells: secrete mucus
Paneth cells:mucusal defense system
Entroendicrine cell
Histology

22. 
2 . Submucosa:
3 . Muscularis
4 .serosa
Histology

23. 
Small bowel obstruction
Definition : arrest of downward propulsion of
intestinal content
Classification :
according to :
A)pathological cause:
1)simple intestinal obstruction
2) strangulated intestinal obstruction
B)onset and course of obstruction
1) acute
2)chronic
C) mechanical Vs Adynamic
D) complete Vs incomplete

24. 
Etiology
■ Intraluminal
Impaction
Foreign bodies
Gallstones
■ Intramural
Stricture
Malignancy
crohn’s disease
Diviticulitis
■ Extramural
Bands/adhesions
Hernia( internal /external )
Volvulus
Intussusception

25. 
Early in the course of an obstruction, intestinal
motility and contractile activity increase in an effort
to propel luminal contents past the obstructing point.
Later in the course of obstruction, the intestine
becomes fatigued and dilates, with contractions
becoming less frequent and less intense…
Pathophysiology

26. 
Abdominal Pain,
Distention ,
nausea
Vomiting
obstipation
Clinical manifestations

27. 
Causes of strangulation
External:■ Hernial orifices ■ Adhesions/bands
Interrupted blood flow ■ Volvulus ■ Intussusception
Increased intraluminal pressure ■ Closed-loop obstruction
Primary ■ Mesenteric infarction
Classic picture of strangulation
tachycardia,
fever,
Leukocytosis
LoclaizedTenderness
Strangulation

28. 
History taking
plain abdominal X-ray (two views should be taken-
erect & supine)+ up right CXR
CT scan
diagnose

29. 

30. 
fluid and electrolyte replacement ,
Antibiotic
NG tube
Foley catheter
CV line
treatment

31. 

32. 
Phisyologic
Pathologic
Paralytic illeus
 Causes of Ileus
Post laparotomy
Metabolic and electrolyte derangements (e.g., hypokalemia,
hyponatremia, hypomagnesemia, uremia, diabetic coma)
Drugs (e.g., opiates, psychotropic agents, anticholinergic
agents)
Intra-abdominal inflammation
Retroperitoneal hemorrhage or inflammation
Intestinal ischemia
Systemic sepsis

33. 
Clinical manifestation:
N/V-distention-obstipation
Diagnose:
CT Scan
Treatment:
conservative
illeus