3. • Introduction to gastrointestinal tract
• Rectum
• Mucosa of rectum
• Submucosa
• Anus
• Mucosa
• Submucosa
• Muscularis externa
• Function of rectum and anal canal
4. The rectum is the last
part of the large
intestine and connects
the sigmoid colon to
the anal canal. The
rectum begins at the
height of S2-S3 and
ends at the perineum.
It is about 12 to 16 cm
5. Anatomicaly Rectum is further subdivided into
three parts
The upper third lies intraperitoneally
The middle third retroperitoneally
The lower third under the pelvic diaphragm and
therefore known as extraperitoneally.
6. Function of the Rectum
It is important for the water resorption as well
as for the resorption of electrolyte from the
stool and plays an important role in the
defecation process.
7. Histological rectum is divided into
Mucosa
Mucosa of rectum is lines by simple columnar
epithelium which contains tall columnar
absorbtive cells, Goblets cells
Lamina propria
Lamina propria of rectum contain large num
of crypts of leiberkuhn that are deeper as
compare to colon's crypts of leiberkuhn
8. Submucosa of rectum consist of
dense connective tissues which
contain blood vessels (superior,
middle, inferior rectal arteries and
veins ) and Meissner`s plexus of
nerves
Submucosa of rectum
9. Like colon it is consist of outer
longitudinal and inner circular layer
but unlike colon its longitudinal
layer is uniform thicknes (and does
not show teniae coli)
Muscularis externa
10. Most of rectum is covered by a
connective tissue adventitia only
anterior and leteral surface of the
upper third of the rectum have a
serosal covering
Adventitia and serosa
