Microsoft PowerPoint - Anatomy Enterohepatic..pdf

7/29/2019 Microsoft PowerPoint - Anatomy Enterohepatic..pdf

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dr.Yani Istadi,M.Med.Ed

Anatomy Enterohepatic


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Anatomy of Liver

3 lb. organ located inferior to the diaphragm

4 lobes -- right, left, quadrate & caudate

round ligament is remnant of umbilical vein

Liver is a large, solid, wedge shaped gland which occupies whole

of right hypochondrium, the greater part of the epigastrium and part

of the left hypochondrium upto the left lateral plane.

ANATOMY OF LIVER

It is the largest gland of the body and contributes about 2%

of the total body weight.

Weighs 1600gm in male and 1300gm in female


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It has five surfaces:

Anterior

Posterior

Superior

Inferior and

Right

It is divided into right and left lobe by falciform ligament

anteriorly and superiorly, by the fissure of ligamentum teres

inferiorly and by the fissure for ligamentum venosum posterioly.

Right lobe is much larger than the left lobe and forms five sixth of

the liver , and also presents the caudate and quadrate lobe.

Porta hepatis is a deep , transverse fissure situated on the inferior

surface of the right lobe.

Portal vein , the hepatic artery and the hepatic plexus of nerves enter

the liver through the porta hepatis while right and left hepatic ducts

and few lymphatics leave it.


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Inferior Surface of Liver


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Hepatic segments.

On the basis of intrahepatic distribution of hepatic

artery, portal vein and biliary ducts, liver is divided

into right and left hemilivers.

Further divided into a total of eight segments.

Each segments have their own hepatic artery branch

and biliary tree.


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Blood supply

80% of blood supply is derived from portal vein.

20% is derived from hepatic artery.

Before entering the liver both hepatic artery and portal vein

divide into right and left branches.

Within the liver they redivide into segmental vessels, which

further divide to form interlobular vessels which run in

portal canals.


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Lymphatic drainage

Superficial lymphatics terminate in:CavalHepaticParacardial andCoeliac lymph node.

Deep lymphatics terminate in:Supra diaphragmatic and

Hepatic lymph node.

Liver receives its nerve supply from hepatic plexus which containsboth sympathetic and parasympathetic or vagal plexus.


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The Gallbladder and Bile

Sac on underside of liver -- 10 cm long

500 to 1000 mL bile are secreted daily from liver

Gallbladder stores & concentrates bile

bile backs up into gallbladder from a filled bile duct

between meals, bile is concentrated by factor of 20

Yellow-green fluid containing minerals, bile acids, cholesterol, bilepigments & phospholipids

bilirubin pigment from hemoglobin breakdown

intestinal bacteria convert to urobilinogen = brown color

bile acid (salts) emulsify fats & aid in their digestion

enterohepatic circulation is recycling of bile salts from ileum


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The sphincter of Oddi, a thick coat of circular smooth muscle,

surrounds the common bile duct at the ampulla of Vater

The arterial supply to the bileducts is derived from thegastroduodenal and the righthepatic arteries, with majortrunks running along themedial and lateral walls of thecommon duct (3 o'clock and 9

o'clock).

Anomalies of the duct


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Anomalies contd

Small ducts (of Luschka) may drain directly from the liver

into the body of the gallbladder. If present, but not

recognized at the time of a cholecystectomy, a bile leak with

the accumulation of bile (biloma) may occur in the abdomen

The gallbladder

Bile leaves the liver via:

Bile ducts, which fuse into the

common hepatic duct

The common hepatic duct,

which fuses with the cysticduct

These two ducts form the bile

duct


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Biliary duct system

Biliary tree (intrahepatic): bile canaliculi --> intralobar bile

ductules --> intrahepatic bile ducts in portal tracts --> left

and right hepatic duct.

Left and right hepatic ducts combine to common hepatic

duct. The confluence of common hepatic duct and cystic

duct (from gall bladder) gives rise to the common bile

duct.

The common bile duct merges with the pancreatic duct

and forms the ampulla of Vater before entering the

duodenum.

Sphincter of Oddi regulates flow into duodenum.

Biliary system (cont.)

Biliary tree (intrahepatic):

bile canaliculi --> terminal bile ductules --> perilobar ducts --> interlobar ducts

--> septal ducts --> lobar ducts --> left and right hepatic duct


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contd

The peritoneal lining covering the liver covers the fundus and the

inferior surface of gall bladder

What is intra-hepatic gallbladder?

Intra-hepatic Gall bladder

The gallbladder has a complete peritoneal covering, and is

suspended in a mesentery off the inferior surface of the liver,

and rarely it is embedded deep inside the liver parenchyma


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Histology

Lined by a single, highly-folded, tall columnar epitheliumthat contains cholesterol and fat globules

The mucus secreted into the gallbladder originates in thetubuloalveolar glands found in the mucosa lining theinfundibulum and neck of the gallbladder, but are absentfrom the body and fundus

The epithelial lining of the gallbladder is supported by alamina propria

What is the histological difference from rest of the GI tract?


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The gallbladder differs histologically from the rest of the

gastrointestinal tract in that it lacks a muscularis mucosa and

submucosa.

Blood supply

Cystic artery that supplies the gallbladder is usually a branch

of the right hepatic artery (>90% of the time).

What is hepatocystic triangle ( calots triangle ) ?


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contd the area bound by the cystic duct, common hepatic duct,

and the liver margin

When the cystic artery reaches the neck of the

gallbladder, it divides into anterior and posterior

divisions


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Anomalies

Veins & Lymphatics

Venous return - small veins that enter directly into the liver,

or rarely to a large cystic vein that carries blood back to the

portal vein.

Lymphatics drain into nodes at the neck of the gallbladder. A

visible lymph node overlies the insertion of the cystic artery

into the gallbladder wall


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Nerves The preganglionic sympathetic level is T8 and T9. Impulses

from the liver, gallbladder, and the bile ducts pass by meansof sympathetic afferent fibers through the splanchnic nervesand mediate the pain of biliary colic.

The hepatic branch of the vagus nerve supplies cholinergicfibers to the gallbladder, bile ducts, and the liver

Gallbladder and Associated Ducts

Figure 23.20


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Gross Anatomy of Pancreas

Retroperitoneal gland posterior to stomach

head, body and tail

Location

Lies deep to the greater curvature of the stomach

The head is encircled by the duodenum and the tail abuts the spleen

Endocrine and exocrine gland

secretes insulin & glucagon into the blood

secretes 1500 mL pancreatic juice into duodenum water, enzymes, zymogens, and sodium bicarbonate

zymogens are inactive until converted by other enzymes

other pancreatic enzymes are activated by exposure to bile and ions in theintestine

Pancreatic duct runs length of gland to open at sphincter of Oddi

accessory duct opens independently on duodenum

Pancreatic

Acinar Cells Zymogens = proteases

trypsinogen

chymotrypsinogen

procarboxypeptidase

Other enzymes

amylase digests starch

lipase digests fats

ribonuclease and

deoxyribonuclease digest

RNA and DNA


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contd

The spleen plays a significant though not indispensable rolein host defense, contributing to both humoral and cell-mediated immunity.

Antigens are filtered in the white pulp and presented toimmunocompetent centers within the lymphoid follicles.

This gives rise to the elaboration ofimmunoglobulins(predominantly IgM).

Following an antigen challenge, such an acute IgM responseresults in the release of opsonic antibodies from the white

pulp of the spleen. Clearance of the antigen by the splenicand hepatic reticuloendothelial (RE) systems is thenfacilitated.

Contd

The spleen also produces the opsonins, tuftsin and properdin

Tuftsin, a likely stimulant to general phagocytic function in the

host, appears to specifically facilitate clearance of bacteria.

Protein properdin is important in the initiation of the alternate

pathway of complement activation.


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Jaundice

acholic


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Fatty metamorphosis (fatty change) of the liver

Liver is slightly enlarged and has a pale yellow

appearance, seen both on the capsule and cut surface


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Ultrasound shows single stone (arrow). Size 1.2 x 0.97 cm

L = liver G = gallbladder

Cholelithiasis: Ultrasound

cystic

duct

common

bile duct

gall

bladder

gall stones


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Multiple stones in gallbladder

Endoscopic view of gallstone

(extracted endoscopically with 'basket' device)


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Bile secretion = digestive/absorptive function of the liver

Components of bile

bile salts (conjugates of bile acids)

bile pigments (e.g. bilirubin)

cholesterol

phospholipids (lecithins)

proteins

electrolytes (similar to plasma, isotonic with plasma)

600-1200 ml /day

Types of gallstones

cholesterol gallstones (most common)

bile pigment gallstones (unconjugated bilirubin)

mixed stones


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mixed stones (cholesterol and bilepigments)

mixed stones (cholesterol and bilepigments)


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Bile Duct Carcinoma:

Rare tumor and about two third are located at the hepatic duct bifurcation

Risk factors: primary sclerosing cholangitis, choledochal cysts, ulcerative

colitis, hepatolithiasis, biliary-enteric anastomosis, and biliary tract infections

with Clonorchis or in chronic typhoid carriers.

95% are adenocarcinoma

Anatomical division:*intrahepatic ; treated like HCC

*perihilar (Klatskin tumors)

*proximal

*distal


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Microsoft PowerPoint - Anatomy Enterohepatic..pdf

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