The pancreas is a soft finely lobulated, elongated exo-endocrine gland . The exocrine part secretes the pancreatic juice and the endocrine part secretes the hormones, viz., insulin etc.
The pancreas is presumably so named because of its fleshy appearance. The pancreatic juice helps in the digestion of lipids, carbohydrates and proteins whereas the pancreatic hormones maintain glucose homeostasis.
Location of Pancreas in Human Body
The pancreas lies more or less horizontally on the posterior abdominal wall in the epigastric and left hypochondriac regions.
Size and Shape
The pancreas is J shaped being set obliquely. The bowl of retort represents its head and the stem of retort represents its neck , body and tail. Its measurement are:
Length ; 12-15 cm
Width ; 3-4 cm
Thickness ; 1.5-2 cm
Weight ; 80-90 g
Parts and relation
The pancreas is divided into four parts-
1- Head
2- Neck
3- Body
4- Tail
Head of the pancreas
It is the enlarged, disc-shaped right end of the pancreas, which lies in the concavity of the C-shaped duodenal loop in front of the L2 vertebra.
External features
The head presents the following external features-
Three borders- Superior, inferior and right lateral
Two surfaces - Anterior and posterior
One process- Uncinate process
Relations of the Head of Pancreas
Relations
Superior border is related to:
a) First part of the duodenum
b) Superior pancreaticoduodenal artery
Inferior border is related to :
a) Third part of the duodenum
b) Inferior pancreaticoduodenal artery
Right lateral border is related to
a) Second part of the duodenum
b) Anterior and posterior pancreaticoduodenal arterial arcades
Anterior surface is related from above downward to:
a) Gastroduodenal artery
b) Transverse colon
c) Root of the transverse mesocolon
d) Jejunum
Posterior surface is related to:
a) IVC
b) Left renal vein
c) Bile duct
d) Right crus of diaphragm
Uncinate process is related to:
a) Anteriorly to superior mesenteric vessels
b) Posteriorly to the abdominal aorta
Neck of the pancreas
It is slightly constricted part of the gland which connects the head with the body. It is about 2.5 cm long and is directed forward, upward and to the left.
External features -
It presents the following external features:
Two surfaces - Anterior and posterior
Two borders - Upper and lower
Relations
a) Anterior surface is related to pylorus
b) Posterior surface is related to commencement of the portal vein
c) Upper border is related to the first part of the duodenum
d) Lower border is related to the root if the transverse
Body of the pancreas
It is elongated part of the gland extending from its neck to the tail . It passes toward the left of midline with a slight upward and backward inclination. It lies in front of the vertebral column at or just below the transpyloric plane.
External features
It is somewhat triangular in cross section and presents:
1- Three borders - Anterior , superior and inferior
2- Three surfaces - Anterior , posterior and inferior
3- One process - omentum
a) Anterior border provides the attachment to the root of the transverse mesocolon
b) Superior border is related to the coeliac artery above the tuber omentale , hepatic artery to the right , and splenic artery to the left of tuber omentale.
c) Inferior border is related to superior to superior mesenteric vessels.
d) Anterior surface is related to lesser sac and stomach.
e) Posterior surface is related to aorta and origin of the superior mesenteric artery , left kidney and left suprarenal glands
f) Inferior surface is related to duodenojejunal flexure, coils of jejunum and left colic flexure.
Tails of the pancreas
It is the narrow left extremity of the pancreas, it lies in the lienorenal ligament along with splenic vessels and it is mobile unlike the other major retroperitoneal parts of the gland. It contains the largest number of langerhans islets unit of tissue as compared to other parts of the gland.
These are related to the visceral surface of spleen between gastric impression and colic impression.
Development
The pancreas develops from two separate buds: the ventral pancreatic bud and the dorsal pancreatic bud.
Arterial supply
The pancreas is a high vascular structure and supplied by the following arteries -
1- Splenic artery, a branch of coeliac trunk
2- Superior pancreaticoduodenal artery
3- Inferior pancreaticoduodenal artery
Venous drainage
The veins of the pancreas drain into
A) superior mesenteric vein
B). Splenic vein
The sympathetic and parasympathetic nerve fibres reach the gland along its arteries from coeliac and superior mesenteric plexuses. The sympathetic supply is vasomotor whereas the parasympathetic supply controls the pancreatic secretion.
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