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1

histology of salivary glands

The secretory units of the salivary glands consist of a branched tubulo-acinar structure. The acinar cells produce either serous, mucous or a mixed saliva. In some cases the serous cells form caps around the mucous secreting acini. These caps are referred to as serous demilunes. Cells which produce serous saliva stain much darker with H&E stain compared to mucous secreting cells.

The acini cells secrete saliva into small intercalated ducts which, in turn, drain into larger striated ducts and then into even larger excretory ducts.

2

histology of the pancreas

The pancreas is a mixed endocrine and endocrine gland. It is surrounded by a thin connective tissue capsule. Septa extend into the gland from the capsule separating the pancreatic lobules.

The exocrine component of the gland is similar to the parotid gland. It consists of closely packed secretory acini which drain into a duct system. The smallest intercalated ducts drain into intralobular ducts which, in turn, drain into interlobular ducts. The interlobular ducts are located in the septa of the gland. The interlobular ducts drain into either the main pancreatic duct or the accessory pancreatic duct.

The endocrine component of the gland is comprised of clusters of cells known as the pancreatic islets (islets of Langerhans). These are scattered throughout the gland but are most numerous in the tail. The islets vary in size and are composed of a number of different cell types, each of which is responsible for secreting one type of hormone.

3

histology of the liver

The liver is covered by a thin capsule, termed Glisson's capsule. The capsule is thicker at the porta hepatis and it surrounds the vessels and ducts as they extend into the gland. The hepatocytes and the sinusoids are surrounded by a fine, supportive reticular network. the liver lobule is also important in the histological sections.

4

porta hepatis

deep fissure in the inferior surface of the liver through which all the neurovascular structures (except hepatic veins) and hepatic ducts enter or leave the liver. It contains: right and left hepatic ducts. right and left branches of hepatic artery. portal vein.

5

gall bladder

The wall of the gall bladder is similar to that of the gastrointestinal tract but it lacks the submucosal layer. The mucosa consists of a layer of simple columnar epithelium and a supporting lamina propria. There is no distinct submucosa and only one muscularis is evident. This is a thin layer which is composed of muscle fibres orientated in many directions. The outer layer of the gall bladder is serosa in parts and an adventia in others

6

biliary tree

liver-right and left hepatic ducts-common hepatic duct-gallbladder-cystic duct-bile duct-hepatopancreatic ampulla-duodenum. If fat is present in the duodenum the sphincter of Oddi (hepatopancreatic sphincter) will be open and bile will be able to enter. In the absence of fat, the sphincter will be closed and the bile will track back up the bile duct, into the cystic duct and into the gall bladder.

7

What is the name given to the hormone that is released by the enteroendocrine cells when fat is present in the duodenum?

cholecystokinin (CCK)

8

what splanchnic nerve provides symp innervation to the gall bladder

greater splanchnic as in the forgut so T5-9

9

which ganglion do postganglionic symp fibres for the gall bladder arise

coeliac

10

which nerve transmits parasymp to the gall bladder

vagus

11

gall bladder blood supply

he arterial supply to the gall bladder is provided through the cystic artery. The custic artery arises from the right hepatic artery. The cystic artery is usually located in the triangle (cystohepatic) between the inferior border of the liver, cystic duct and common hepatic duct.
Venous drainage - the fundus and body is drained directly through the visceral surface of liver into hepatic sinusoids. the neck and cystic duct are drained by cystic veins which drain into the liver directly or via portal vein.

12

lymphatic drainage of the gall bladder

cystic nodes-hepatic nodes-coeliac nodes-intestinal trunk-cisterna chyli-thoracic duct-left subclavian vein

13

fundus of gall bladder

Rounded portion of the gall bladder that projects from the lower border of the liver. Located at the tip of the 9th costal cartilage in the midclavicular line.

14

body of the gall bladder

Main part of gall bladder that is located posterior to the liver, superior part of duodenum and the transverse colon.

15

neck of the gall bladder

The part of the gall bladder which is continuous with the cystic duct, it lies superior to the duodenum.

16

innervation of the liver

symp by greater splanchnic as in forgut, goes into coeliac ganglion. Vagus does parasymp.

17

lymphatic drainage of the liver

The liver produces up to half the lymph that is made in the body. Most of the lymph from the liver drains into the hepatic nodes which are located at the porta hepatis.

18

portal/systemic anastomoses

Anastomoses between the hepatic portal system and the systemic circulation allow communication between the two vascular systems. If portal circulation through the liver is obstructed blood can return to the heart via the systemic circulation. As the portal vein and its tributaries have no valves the blood can flow in a retrograde direction to the IVC.

19

anastamoses at the inferior oesophagus

Lower third drains via left gastric vein into portal vein - middle third drains into azygos vein.

20

anastamoses at anal canal

Superior rectal veins drain into portal system - middle and inferior rectal veins drain into internal iliac and internal pudendal veins.

21

anastamoses at secondary retroperitoneal structures

Superior mesenteric, inferior mesenteric and splenic vessels drain into portal system - renal, lumbar and phrenic veins drain into IVC.

22

anastamoses at anterior abdominal wall

Paraumbilical veins drain into portal system – superficial veins of abdomen drain into axillary or femoral veins.

23

vascular supply of the liver

hepatic artery proper delivers 20-25% of blood to the liver, which comes from the common hepatic artery. The hepatic artery proper bifurcates into right and left hepatic arteries which enter the liver at the porta hepatis.The portal vein (hepatic portal vein) delivers 75-80% of blood to the liver. It transports blood poor in oxygen but rich in nutrients from the abdominal organs to the liver.The portal vein is formed posterior to the neck of the pancreas. The splenic and sup mesenteric make the portal vein.

24

blood flow of the liver

branches of the hepatic artery and portal vein enter the portal triad. blood is conveyed through the liver sinusoid, drains into the central vein, into the R or L hepatic vein, the vessels drain into the inf vena cava.

25

liver lobule

The liver is a solid organ composed of tightly packed epithelial cells (hepatocytes). The classical description of the liver suggests that the basic structural unit of the liver is the liver lobule. Each lobule is hexagonal in shape and consists of plates of hepatocytes radiating towards a central vein. Vascular channels, the liver sinusoids, are placed between the plates of hepatocytes. They convey blood from the periphery of the lobule to the central vein. A portal triad is located at each angle of the hexagonal lobule. Each portal triad contains a branch of the hepatic artery and of the portal vein (which deliver blood to the lobule) and a small bile duct. Bile is secreted by the hepatocytes into small bile canaliculi which are located between adjacent hepatocytes. The canaliculi drain into the small bile duct at the portal triad. This arrangement is designed so that blood and bile don't mix.

26

falciform ligament

A double fold of peritoneum that connects anterior & superior surfaces of the liver to the anterior abdominal wall.

27

ligament teres

Remnant of the umbilical vein, it runs in the free edge of the falciform ligament.

28

ligamentum venosum

Remnant of the ductus venosus, it is attached to the portal vein and the IVC.

29

coronary ligament

A reflection of visceral peritoneum that extends from the posterior surface of the liver onto the diaphragm.

30

right triangular ligament

The right extremity of the coronary ligament.

31

left triangular ligament

The left extremity of the coronary ligament.

32

hepatogastric ligament

The part of the lesser omentum which extends from liver to lesser curvature of stomach.

33

hepatoduodenal ligament

The free border of the lesser omentum, it contains the bile duct, portal vein and hepatic artery.

34

lobes of the liver

right left caudate quadrate. Right and left seperated falciform.

35

liver relations

in R and L hypochondriac and epigastric. The liver has two surfaces; diaphragmatic and visceral. The diaphragmatic surface is smooth as it is moulded by the under surface of the diaphragm. In contrast the visceral surface is irregular as it is in contact with the irregular shaped viscera. anterior to liver: ant abdom wall. xiphoid process.costal margins. pleura. lungs.
posterior to liver: gall bladder. duodenum. stomach, hepatic flexure. IVC. Oesophagus. R kidney. colon

36

vascular supply of the pancreas

The head (including ucinate process) of the pancreas are supplied by the superior and inferior pancreaticoduodenal arteries. The remainder of the pancreas is supplied by the splenic artery. superior PD is a branch of GD, which comes from the CH. the IPD comes from SM. The head of the pancreas is drained by the superior and inferior pancreaticoduodenal veins. The remainder of the pancreas is drained by the splenic vein.

37

pancreatic ducts

The secretory acini cells secrete pancreatic juice into a series of ducts. The duct system empties into the second part of the duodenum via the main pancreatic and accessory pancreatic ducts. accesory just drains the head. the main joins common bile to go to major duodenal papilla. Accesory can be absent. The flow of bile and pancreatic juice into the duodenum is controlled by the hepatopancreatic sphincter, this sphincter also prevents reflux of duodenal content back into the pancreatic and bile ducts.

38

what plane is the pancreas

transpyloric

39

relations of the pancreas

Anterior: transverse mesocolon. lesser sac. stomach. transverse colon. GDA.
Posterior: aorta. Splenic vein. left suprarenal gland. IVC. Bile duct. SMA. left psoas muscle. hilum of spleen. left kidney. renal vessels. PV.