3. FUNCTIONAL ANATOMY
SMALL INTESTINE
Gross Anatomy.
Extend – from Pylorus
to the Ileocaecal Valve
Length – 6-7m.
Divided into 3 parts
Duodenum
Jejunum
Ileum.
Thursday, September 27, 2018
4. FUNCTIONAL ANATOMY
Duodenum –
First, shortest & most
fixed.
C shaped
4 parts –
Superior (Duodenal Cap)
most common site for
Peptic Ulcer.
Descending – Ampulla of
Water opens
Horizontal &
Ascending.
Thursday, September 27, 2018
6. FUNCTIONAL ANATOMY
LARGE INTESTINE
Gross Anatomy.
Extend – from the Ileocaecal Valve
to Rectum.
Length – 100 cm.
Divided into 3 parts
Caecum
Appendix
Ascending Colon
Transverse Colon
Descending Colon
Sigmoid colon & rectum and Anal
Canal
Thursday, September 27, 2018
7. ILEOCAECAL VALVE
Structure – valve is due to Invagination of ileum
into Caecum.
Function – to prevent backflow of faecal matter
from Caecum into ileum.
Role of Ileocaecal sphincter –sphincter is
thickened band of circular muscle coat of terminal
ileum.
Control – Gastrin – relaxes.
Secretin – Contracts.
Thursday, September 27, 2018
9. MUCOUS MEMBRANE
Length of small intestine – 6
meter.
Absorptive area – 250m2
due to
Plicae Circularis –
Numerous folds of intestinal
mucosa
Villi
Microvilli along with crypts
of Liberkuhn (Depressions)
Thursday, September 27, 2018
10. PLICAE CIRCULARIS
Numerous folds
Absent in Duodenum
Contains all layers of
mucosa
Lining epithelium, lamina
Propria, Muscularis Mucosa.
Submucosa
Functions – Increase surface
area & Decreases passage &
fascilitate absorption.
Thursday, September 27, 2018
11. VILLI
Finger like projections
of mucous membrane
Total number – 4-5
millions
20-40 villi/mm2
Length – 0.5-1mm
Thursday, September 27, 2018
12. VILLI
Structure –
Each villus covered – single layer
of columnar epithelia cells-
enterocytes.
Core contains – artery venule &
Lymphatic vessel & nerve network
Activity – during Digestion &
absorption –villi contracts &
relax slowly & pump Lymph
from core to submucosal lacteal.
Thursday, September 27, 2018
13. THE CRYPTS OF LIBERKHUN.
These are Tubular
intestinal glands which
invaginate deep into lamina
propria between villi
throughout small intestine.
Epithelial cells of mucous
membrane of small
intestine & intestinal
glands.
Thursday, September 27, 2018
14. THE CRYPTS OF LIBERKHUN.
Absorptive columnar cells
Undifferentiated
columnar cells
Goblet cells
Argentaffin or
Enterochromaffin cells
Zymogen cells or Paneth
cells
Duodenal glands of
Brunner
Peyer Patches.
Thursday, September 27, 2018
15. STRUCTURAL CHARACTERISTICS
OF LARGE INTESTINE
Histologically similar to
small intestine except –
Absence of plicae
circulares & Villi
Large number of Crypts
of Liberkhun with goblet
cells – secrete Mucus.
Epithelium Overlying
lymphatic follicles
contains M cells.
Thursday, September 27, 2018
16. LONGITUDINAL LAYER OF
MUSCLE COAT
Unusual
Forms 3 thick Bands – “Taenia
Coli”
Shorter in Length, than other
layers of colon forms
Sacculations called “
Haustrations”
Serous layer – missing over
posterior aspect.
Small peritonial bags of fat
“Appendices epiploicae”
Thursday, September 27, 2018