1. Practical demonstration of gross
anatomy & histology of Jejunum,
Ileum,Appendix and Colon
By
Dr. Abdul Waheed Ansari
Chairperson &Prof. Anatomy,
RAKCOMS. RAKMHSU.
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2. Learning outcomes of the lab are:-
• 1. Identify the different segments of small
intestines-Duodenum, Jejunum and Ileum.
• 2. Identify the gross features of large intestines-
appendix, ascending colon, transverse colon,
descending colon, sigmoid colon, rectum and anal
canal.
• 3. Histological features of ileum, jejunum,
appendix and colon.
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3. Features of duodenum
• It is the first part of small
intestines, 25 cms long.
• It is retroperitoneal except
first inch of first part of
duodenum.
• It has four parts, C shaped.
• Second part has opening of
CBD and pancreatic ducts,
major duodenal papilla and
minor duodenal papilla.
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4. The Jejunum is the second portion of small
intestines
• It starts from duodenojejunal
flexure to ileocaecal junction.
• The proximal 1/3rd are the
jejunum loops and distal 2/3rd
are the loops of ileum.
• The jejunum loops are more
muscular and more vascular
where as ileal loops are thin
walled and less vascular,
interior shows plicae circularis.
• Internally ileum have Payer’s
patches.
• The plicae circularis are few in
the ileum.
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5. The arterial supply of jejunum and
ileum
• The superior mesenteric
artery is the artery of
midgut.
• It gives jejunal branches
and ileal branches and
terminates as ileocaecal
artery.
• The accompanying vein
joins the splenic vein to
form the portal vein.
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6. Histology of Jejunum
• The mucosa of the small
intestine is lined by simple
columnar epithelium which
evaginates into villi.
• The epithelium of villi is
continuous with that of
adjacent crypts.
• Lamina propria of the small
intestine forms the core of
villi and surrounds the crypts.
• The muscularis mucosa of
the small intestine forms a
thin layer.
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7. 12/18/2014 7

8. Ileum
• The Peyers patches are found
in the ileum.
• They are found at the
antimesentreric border.
• Histology of Ileum is
characterized by submucosa
having lymphoid tissue-
Peyer’s patches
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9. Appendix
• The human's appendix averages
11 cm in length but can range
from 2 to 20 cm.
• The diameter of the appendix is
usually between 7 and 8 mm
• It has no haustrations, no taenia
coli and no plicae circularis and no
Peyer’s patches and no
appendices epiploicae.
• It has a mesentery of its own,
carrying the artery to appendix.
• The tip of the appendix can have a
variable position within the
abdominal cavity :
• retro-caecal (65-70%)
• pelvic (25-30%)
• pre- or post-ileal (5%)
• Inflammation is called as
appendicitis.
• Pain will be felt around umbilicus
because of referred pain-T10
segment dermatome.
• The arterial supply- appendicular
artery, a branch of the ileocolic
artery which is a branch of the
superior mesenteric artery.
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10. Normal appendix
ultrasound image
longitudinally
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Appendicitis –perforation detected
by sonography

11. Sonography of swollen and inflamed
appendix longitudinal section
• Appendicitis shows up as a
tubular structure that does
not push out of the way or
compress, often with
changes in the adjacent fat
from the inflammation.
• This will often cause the
patient to say, “Ouch, that
is where it hurts.”
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12. Histology of appendix
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13. Colon histology
• The mucosa is having
simple columnar
epithelium with lots of
mucus glands-goblet
cells. Simple tubular
intestinal glands.
• Submucosa having
neurovascular bundles.
• Muscularis external
having both circular and
longitudinal fibers- taenia
coli are longitudinal
bundles
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14. The large intestines
• The caecum, appendix ,
ascending colon, transverse
colon, descending colon,
sigmoid colon, rectum and anal
canal are parts of large
intestines.
• It is supplied by branches from
superior and inferior
mesenteric arteries.
• At the anal canal there is
anastomosis between systemic
veins and portal veins, hence
one of the sites for anal
hemorrhoids formation.
• It shows haustrations, taenia
coli, appendices epiploicae, all
typical features of large
intestines, except appendix
rectum and anal canal.
• The anal canal has dual
epithelial lining, upper part
simple columnar and lower part
stratified squamous non
keratinized.
• The anal canal has two
sphincters, external and
internal. External anal sphincter
is voluntary where as internal is
involuntary.
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15. Large intestines
external features
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16. The anal canal
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17. References
• http://www.studyblue.co
m/notes/note/n/anal-
triangle/deck/8502291
• http://ect.downstate.edu
/courseware/haonline/lab
s/L39/130202.htm
• http://histologyatlas.wisc.
edu/slides/398
• http://quizlet.com/17115
737/27-digestive-system-
flash-cards/
• http://www.ultrasoundca
ses.info/Cases-Home.aspx
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