Download Accessory Organs

Accessory Organs
 Liver
 Pancreas
 spleen
 Gall
bladder
The Liver
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The largest gland in the body
Weighs about 1.5kg
 Location – under the diaphragm on the right
Found in the upper abdominal cavity: extends from right upper quadrant
to left upper quadrant of the abdomen
Attached to diaphragm by
 Falciform and coronary ligaments
 Left and right triangular ligaments
 Functions:
Bile production and secretion
Detoxification
Storage of glycogen
Protein synthesis
Production of heparin and bile pigments
Erythropoiesis (in fetus)
The Liver
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Anatomically has four lobes – right, left, caudate, and
quadrate
The falciform ligament:
 Separates the right and left lobes
 Separate the subphrenic recess made by the peritoneum
 Suspends the liver from the diaphragm and anterior
abdominal wall
The ligamentum teres:
 Is a remnant of the fetal umbilical vein
 Round ligament in the inferior surface
 Runs along the free edge of the falciform ligament
 Ligamentum venosum inferior surface remnant of fetal
ductus venosus
 Functional
lobes
 Rt and Lt lobes
 Portal lobes are two equal lobes (sagittal plan)
 Further divided in 8 segments based on
principal branches of Hepatic art. Vien, and bile
duct
 Divided into 4 anatomical lobes
 Left
 Right
 Caudate Post
 Quadrate nt
Surfaces of the Liver
Figure 24.19b, c
1.Diaphragmatic surface
Posterior surface
The Liver Superior surface
2. Visceral surface
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Covered by visceral peritoneum except porta hepatis and gall
bladder bed.
The visceral surface is related to:
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Right side of the stomach i.e. gastric and pyloric areas
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Superior part of the duodenum i.e. duodenal area
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Lesser omentum
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Gall bladder
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Right colic flexor
and right transverse area ; colic area
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Right kidney
and suprarenal gland; Renal area
The Liver Inferior surface
1.
2.
3.
The round
ligament(ligamentum teres) –
obliterated umbilical vein
The ligamentum venosum –
fibrous remnant of fetal ductus
vein
The Porta hepatis (hepatic
potal; portal fissure) transverse fissure on the visceral
surface of the liver.
 It gives passage to the:
1. Portal vein
2. Hepatic artery
3. Hepatic nerve plexus
4. Hepatic ducts
5. Lymphatic vessels
Peritoneal relations of the Liver
The Lesser omentum
 Encloses the portal triad (bile duct, hepatic artery and portal vein )
 Passes from the liver to lesser curvature of the stomach + 2 cm of
duodenum
 Thick free edge -- hepatoduodenal ligament
 Sheet like remainder – hepatogastric ligament
Microscopic Anatomy of the Liver
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Hexagonal-shaped liver lobules are the structural and
functional units of the liver
 Composed of hepatocyte (liver cell) plates radiating
outward from a central vein
 Portal triads are found at each of the six corners of each
liver lobule
Portal triads consist of a bile duct and
 Hepatic artery – supplies oxygen-rich blood to the liver
 Hepatic portal vein – carries venous blood with nutrients
from digestive viscera
Figure 23.14d
Microscopic Anatomy of the Liver
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Liver sinusoids – enlarged, leaky capillaries located
between hepatic plates
Kupffer cells – hepatic macrophages found in liver
sinusoids
Hepatocytes’ functions include:
 Production of bile
 Processing bloodborne nutrients
 Storage of fat-soluble vitamins
 Detoxification
Secreted bile flows between hepatocytes toward the bile
ducts in the portal triads
Figure 23.14b
Figure 23.14c
Blood Supply of Liver
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Hepatic artery provides oxygenated blood
Hepatic portal vein provides deoxygenated blood
 Nutrients,
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drugs, toxins, microbes
Hepatic artery and vein carry blood to sinusoids
 Substances
exchanged by hepatocytes
 Blood drains to central vein and eventually hepatic
vein
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Portal triad
 Hepatic
portal vein
 Hepatic artery
 Bile duct
Histology and Blood Supply of the Liver
Fig. 24.20
Liver: Associated Structures
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The lesser omentum anchors the liver to the stomach
The hepatic blood vessels enter the liver at the porta
hepatis
The gallbladder rests in a recess on the inferior
surface of the right lobe
Bile leaves the liver via
 Bile ducts which fuse into the common hepatic duct
 The common hepatic duct fuses with the cystic duct
 These two ducts form the bile duct
Bile Duct System
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Bile secreted by hepatocytes
Bile canaliculi
Bile ducts
Right and left hepatic ducts
Common hepatic duct
Common bile duct
Gallbladder for temporary storage of bile
Cystic duct
Figure 23.13a
Figure 23.13c
The cystic duct is about 2.5
cm in length. Internal
projections of circular
 Location – underside of the
muscle fibers account for the
right lobe of the liver
 Connected to the liver by the spiral valve of Heister, which
makes the passage of calculi
hepatic duct
difficult.
 Connected to the duodenum
The common hepatic duct is
by the common bile duct
usually less than 2.5 cm
 The functions of the
long, and is formed by the
gallbladder is to concentrate union of the right and left
and store bile
hepatic ducts.
 Gallstones
The common bile duct,
about 7.5 cm long, is formed
by the junction of the cystic
and the common hepatic
ducts.
The Gallbladder
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The anatomical subdivisions are,
a fundus, a body, and a neck
which terminates in the narrow
infundibulum.
The angulated distal part of the
neck forms a pouch, called
Hartmann’s pouch, a common
site for a solitary gall-stone to
lodge.
The muscle fibers in the wall of
the gall-bladder are arranged in a
criss-cross manner, being
particularly well developed in the
neck.
The mucous membrane contains
indentations of the mucosa that
sink into the muscle coat - these
are the crypts of Luschka.
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The wall of the gallbladder is
composed of three layers:
mucosa ; muscularis and serosa.
There is no muscularis mucosae
or submucosa.
There are different sized
branching folds lined by single
layer of columnar cells with a pale
cytoplasm and basally located
nuclei.
The lamina propria is composed
of loose connective tissue, blood
vessels, nerves and some
plasma cells.
The muscle layer is composed of
haphazardly distributed bundles
of smooth muscle fibers.
Pancreas
Mixed endocrine and exocrine gland
 Exocrine  compound acinar gland, similar
in structure to parotid gland.
 Distinction between 2 glands can be made
based on absence of striated ducts and
presence of islets of Langerhans.
 Initial portions of intercalated ducts
penetrate lumens of acini.
 Centroacinar cells constitude interacinar
portion of intercalated duct.
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Pancreas –all flesh
Introduction…
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Soft, lobulated elongated
gland with both exocrine
and endocrine functions
Exocrine –pancreatic juice
Endocrine-insulin
Location….
epigastric & left
hypochondriac
regions
behind the stomach in the
lesser sac
Transversely across the
posterior abdominal wall
at the level of the L2 & L3
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Size and shape…
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Parts …
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J shaped or retort
shaped.
Length-15-20 cm
Thickness1.2-1.8 cm
Breadth-2.5 -3.8 cm
Wt-90 gm
Head …
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Enlarged part C shaped, lying
within the concavity of
duodenum, consist of
3 borders-superior ,inferior &
right lateral
2 surfaces-anterior &
posterior
uncinate process
Posterior surface relation:
 IVC
 Right Renal veins
 Right crus of diaphragm
 Bile duct
 Stomach
 Lesser omentum
Head …
Superior border-1st part of duodenum
-Sup. pancreaticodudenal A.
 Inferior border-3rd part of duodenum
-Inf. pancreaticodudenal A.
 Rt. lateral border-2nd part of duodenum
-Terminal part of bile duct
-Anastomosis betn 2 arteries.
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Uncinate process…
Triangular projection
which arises from
lower and left part off
the body.
Relations:
• Anterior:
-Superior mesenteric
vessels.
• Posterior
-Aorta
• Above
-Left renal vein
Neck…
Relations:
Anterior surface
 Peritoneum covering
lesser sac
 Pylorus
Posterior surface
is related to
 superior mesenteric
vein
 portal vein
Body…
Elongated part.
 Extends from neck to the tail.
 Passes toward the left with
slight upward and backward
inclination
Triangular in cross section
• 3 borders-Anterior
-superior
-Inferior
• Tuber omentale -small
projection on superior border
little to the left of the neck
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Body-Relations…
Borders:
• Anterior attach to root of the
tranverse mesocolon .
• Superior related to coeliac
trunk, hepatic artery & splenic
artery
• Inferior is related to superior
mesenteric artery.
Surfaces:
• Anterior is convex covered by
the peritoneum related to the
lesser sac & stomach.
• Inferior surface covered by the
peritoneum related the DJ
flexure coils of jejunum & Lt.
colic flexure.
Body –relations…
Posterior surface
-Aorta
-Left crus of the
diaphragm
-Left kidney
-Left Suprarenal gland
-Left renal vessels
-Splenic vein
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Tail …
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Left end of the
pancreas
Lies in the lienorenal
ligament ,together with
the splenic vessels
Related to the lower
part of the spleen
(gastric surface.
Ducts system…
Exocrine part of pancreas
is drained by the 2 ducts
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Main
Lies near posterior
surface ,3 mm in
diam.white in colour
Begins at the tail, runs
throughout the body
,bends at the neck to run
downwards backwards in
the head.
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Herring bone pattern
Accessory.
The accessory duct
Begins in the lower part of head, crosses the main
duct with which it communicates
Opens as minor duodenal papilla in the 2nd part of
duodenum (6-8 cm distal to pylorus)
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In the head of the pancreas, it
is related to the bile duct(on rt.
side)
Two ducts open in the wall of
the 2nd part of the duodenum
and join to form
hepatopancreatic ampulla
of vater which open as major
duodenal papilla,8-10 cm
distal to pylorus.
Arterial supply…
-Splenic A.
-Superior pancreaticoduodenal artery
(from coeliac trunk)
-Inferior pancreaticoduodenal A.(from
superior mesenteric A)
Nerve supply…
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Parasympathetic by
the vagus nerve
controlling secretion .
Sympathetic from
coeliac & superior
mesenteric plx.
Secretion is also
controlled by
harmone secretinpancreozymine.
Lymphatic drainage…
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Head & neck –ventral
& dorsal
pancreaticodudenal
grp LN.
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Body &tail by
pancreatico-splenic
LN.
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Efferents to Coeliac &
sup.mesenteric LN
Pancreas
Figure 24.26a