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° 
THE PANCREAS 1073 
The two original outgrowths which open into the foregut close together, are soon 
succeeded by an evagination of the wall of the duodenum, which embraces the orifices of 
both, and subsequently forms the common bile duct ; 
whilst the two primary diverticula, 
which are now connected with the evagination, form the right and left hepatic ducts. 
The interlobular bile duets and ihe bile capillaries are 
formed by a canalisation of 
the primitive hepatic cylinders which have been budded off from the original diverticula. 
And the gall-bladder is formed as an outgrowth from the common bile duet. 
As ‘ate liver 
versuin into the abdominal cavity, so that now, 
septum, it looks like 
an appendage of its 
under surface. In other 
words, the septum be- 
gins to differentiate into 
two parts—a lower, the 
liver, and an upper 5 
which constitutes the 
greater portion of the 
diaphragm, both of these 
having been at first one 
continuous mass. In-the 
course of development 
the separation of the 
two becomes more 
marked, and finally is 
complete everywhere ex- 
cept at the coronary and 
lateral hgaments behind, 
and at the falciform liga- 
ment in front, where they 
are still connected. 
As the liver separates 
off from the future dia- 
phragm, and descends 
into the abdomen, there 
descends with it the ventral mesentery 
duodenum with the anterior 
stretching 
which becomes the 
to the anterior wall of the 
In early foetal life the liver is relatively of enormous size. 
—a_ posterior, 
liver, 
increases in size, it begins to project down from the septum trans- 
instead of being situated within the 
Ventral mesentery 
| rear 
(sophagus Liver 
Ni | | Ventral mesentery 
c | Bi 5 
Stomach, Bile duct 
q : Stomach 
Spleen 
F Diaphragm 
< 4 Spleen 
Li 4 Line crosses 
INAS: 4. mesogastrium 
Pancreas 
sta. —Pancreas 
_ Superior mesen- 
teric artery 
Small intestine 
Duodenum 
Superior mesen- 
teric artery A 
Small 
intestine™ 
=- Colon 
Aj Inferior mesen- 
j teric artery 
Inferior mesenteric artery Rectum 
ke 
Rectum 
Tlie mesentery 
Aorta 
Fic. 722.—Two DIAGRAMS TO ILLUSTRATE THE DEVELOPMENT OF THE 
INTESTINAL CANAL. 
The figure to the right shows the rotation of the intestinal loop round the 
superior mesenteric artery. In both figures the parts are supposed to be 
viewed from the left side. 
a fold which connects the stomach and 
abdominal wall. This is divided by the liver into two parts 
from the front (lesser curvature) of the stomach to the 
lesser omentum ; and an anterior, stretching from the liver 
abdomen, which forms the falciform ligament. 
Up to the fourth or fifth 
month it almost completely fills the abdominal cavity, leaving but a small space below 
for the intestines. 
Subsequently its relative size is not so great ; 
but even at birth it 
‘still occupies nearly half of the abdomen, and forms about > th of the body weight, whilst 
in the adult it is reduced to goth. 
subsequently, the right grows more rapidly than the left, so that at birth it is about 
size ; 
twice, and in the adult four times, as large as the left. 
At first the right and left lobes are nearly equal in 
In the foetus, and at birth, the 
caudate and Spigelian lobes are relatively larger than in the adult. 
The changes which take place during development in the vessels connected with 
the liver are described on page 8&4. 
THE PANCREAS. 
The pancreas is an elongated glandular mass which hes transversely on the 
posterior abdominal wall, 
duodenum (Fig. 723), 
in the concavity of the 
It secretes a 
maith its right end resting 
and its left end touching the spleen. 
digestive fluid—the pancreatic juice—which is conveyed to the duodenum by 
the pancreatic duct, and coustitutes one of the chief agents in proteid digestion. 
The absence of a true capsule, and the resulting distinct lobulation of the gland, 
give t 
he pancreas a very characteristic appearance (Fig. 
723), 
Position.—The ereater part of the gland hes in the epigastrium, but the tail 
and adjacent part of ‘the body extend into the left hypochondrium. 
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