The alimentary canal develops during the 4th week of gestation from three embryonic structures - the stomodium, primitive gut, and cloacal membrane. The primitive gut forms as the dorsal yolk sac incorporates into the embryo. It consists of the foregut, midgut, and hindgut. The midgut rapidly elongates, forming loops that project into the umbilical cord in a physiological umbilical herniation. By 10 weeks, the intestines return to the abdominal cavity as it enlarges. Hernias and appendicitis are diseases that can affect the alimentary canal.

1. ORGANOGENESIS OF
ALIMENTRY CANAL

2. ALIMENTRY CANAL
 Endoderm is in the form of flat sheet, is converted into
tube by formation of head, tail and lateral folds of
embryonic disc.
 This tube is called GUT.
 It consist of foregut, midgut, hindgut.

3. DEVELOPMENT OF THE
ALIMENTRY CANAL
 It constitutes during the 4th week from 3 separate
embryonic analoges (organs) 
 The stomodium – develops on the cephalic end of the
embryo.
 The primitive gut – arises by incoporation of the dorsal
part of the yolk sac into embryo during cephalocaudal
and lateral folding of the embryo- gut is connected to the
yolk sac by means of the vitelline duct.
 Cloacal membrane the proctodeum develops on the
caudal end of the embryo b/w future bases of lower
limbs.

4. Segments of the primitive gut
 Foregut.
 Midgut.
 Hindgut.
Gut Is suspended from the ventral and dorsal body wall by
mesenteries.
 During further development midgut rapidly grows in length to form 2
loops, rotates and leaves even the abdominal cavity.

5. The derivatives of the midgut
 Duodenum.
 The caecum, appendix , ascending colon, and the right
half to 2/3rd of the transverse colon.
 Midgut derivates are supplied by the superior
mesentric artery.
 As the midgut elongates, it formes a vental U-shaped
loop of gut, the midgut loop.
 It projects into the remains of the extraembryonic
coelom in the proximal part of the umbilical cord.

6.  At the 10th week stage the extraembryonic coelom
communicates with extraembryonic coelom at the
umbilicus.
 This movement of the intestine is a physiological
umbilical herniation.
 Umbilical herniation occurs because there is not
enough room in the abdomen for the rapidly growing
midgut.

9. RETURN OF MIDGUT LOOP TO
ABDOMEN
 During the 10th week the intestines return to the
abdomen.
 The decrease in the size of the liver and kidneys and the
enlargment of the abdominal cavity are imporatnt factors.
 This process is called reduction of the physiological
midgut hernia.
The small intestine formed from cranial limb returns first.
 It passes posterior to the superior mesentric artery and
occupies the central part of the abdomen.
As the large intestine returns, it undergoes further 180ñ
counterclock wise rotation.
Later it comes to occupy the right side of the abdomen.

10. DISEASES OF ALIMENTRY CANAL
1. HERNIATION( HERNIA) 
Hernia is the abnormal
exit of tissue or an organ, through the wall of the cavity in
which it normally resides.
OR
It is a medical condition, if an organ or its tissue moves
from its normal position through to another position.
There are various types of hernia, most hernias
happens in abdomen.

11. 2. APENDIX 
The apendix sits at the junction of the small intestine and
large intestine.
It’s a thin tube about four inches long.
The function of the apendix is unknown.
But one theory is that the apendix acts as a storehouse
for good bacteria, “rebooting” the digestive system after
diarrheal illness.

12. THANK YOU