Biologia

Introduction

LIVER
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion. The liver is necessary for survival; there is currently no way to compensate for the absence of liver function long term, although liver dialysis can be used shortterm.
GALL BLADDER
In vertebrates the gallbladder (cholecyst, gall bladder, Biliary Vesicle) is a small organ that aids mainly in fat digestion and concentrates bile produced by the liver. In humans the loss of the gallbladder is usually easily tolerated.
EXOCRINE PANCREAS
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producingseveral important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist the absorption of nutrients and the digestion in the small intestine. These enzymes help to further break down the carbohydrates, proteins, and lipids in the chyme.


INDEX

Introduction…..Objectives ……

Content……….

Conclusions…..

Annexes………

Bibliography….

Objectives

1. Recognize liver, gall bladder, and pancreas.

2. Identify and understand the functional significance of the vascular supply and bile drainage of theliver.

3. Identify and discuss the structural and functional arrangement of the classical hepatic lobule, portal lobule, and the liver acinus.

4. Identify bile canaliculi and perisinusoidal spaces of Disse in the liver at the light and electron micrograph level.

5. Recognize the hepatocyte organelles and inclusions in electron micrographs and give their function.

6. Identifyexcretory ducts, interlobular ducts, intercalated ducts, acinar and centroacinar cells in the pancreas. You should also be able to distinguish between the islets of Langerhans and the remaining parenchyma of the pancreas.

Liver, Pancreas, and Gallbladder

Location of the Liver
The liver, the largest internal organ in the body, is situated under the diaphragm. It is further protected by thecostal cartilage of the ribs. The liver is so large that it occupies most of the right hypochondrium as well as part of the abdomen. It is, for the most part, covered by peritoneum and entirely by connective tissue. The upper surface of the organ fits nicely against the undersurface (inferior aspect) of the diaphragm.
There are, on the surface, four lobes: right, left, caudate and quadrate. TheFalciform ligament divides the liver into two main lobes, right and left, with the right lobe being the larger and is sub- divided into the right lobe proper, the caudate lobe and the quadrate lobe.
The undersurface of the liver, also known as the visceral surface, is more irregular in appear- ance than is the domed convex uppersurface. This irregularity is caused by the fact that the infe- riorsurface is in contact with:
1. the lower esophagus
2. the stomach, and
3. the right kidney and adrenal gland
Location, Structure and Function of the Liver
The liver is essential for life, yet it can suffer extensive damage before malfunction becomes pronounced. Although functionally complex, histologically, the liver is nothing more than a greatly modified tubular gland.
Surroundedby a fibrous capsule, the liver is made up of liver lobules (the functional units of the liver). Each lobule is constructed around a central vein that empties into the right and left hepatic veins which then drain into the vena cava.
The lobule is composed of cellular plates that radiate from the central vein. Each cellular plate is two cells thick and between the two cells are small bile...