Hepatocytes

I. INTRODUCTION

What are Hepatocytes?

Hepatocyte means; “hepato-“ pertaining to the liver, and “-cyte” is a cell.

A hepatocyte is a liver cell. Cells are the smallest functional units of the body. They combine to make up tissues, which then combine with other tissues to make organs.

Specialized cells, such as hepatocytes, are often given a more specific name.

In the body, disease happens at the cellular level.

In this work we will give to know more detail about the Hepatocytes. Why are they important? , On which part of the body are specialized and located?

Some of those questions were going to answer so we can have a clear idea of what is the importance of these cells.

II. THEORY

• Mitosis

Biological meaning: All living organisms use cell division, either as playback mechanism, or as a mechanism of growth of the individual. The single-celled beings used cell division for the reproduction and perpetuation of the species, one cell divides into two cells genetically identical daughters and identical to the original, while maintaining the chromosome number and the genetic identity of the species. In multicellular organisms, cell division becomes a cyclical process aimed at the production of multiple cells, all identical between themselves, but that may later result in a specialization and differentiation within the individual.

• Interphase

The cell cycle stage between nuclear divisions, when chromosomes are extended and functionally active. The metabolically active non-dividing stage of the cell cycle.

Pon aqui mas info del libro!!!!

http://groups.molbiosci.northwestern.edu/holmgren/Glossary/Definitions/Def-I/interphase.html

http://www.ucm.es/info/genetica/grupod/mitosis/mitosis.htms

III. SPECIALIZATION

Hepatocytes from the periportal and perivenous zones of the liver parenchyma differ in their enzyme content and subcellular structures and those have different metabolic capacities. Therefore the model of metabolic zonation proposes a functional specialization for the two zones:

1) Oxidative energy metabolism with beta-oxidation, amino acid catabolism, urea genesis, gluconeogenesis for the synthesis of glucose and glycogen, cholesterol synthesis, bile formation, and protective metabolism are predominantly located in the periportal zone

2) Glycolysis, glycogen synthesis from glucose, liponeogenesis, ketogenesis, glutamine formation, and xenobiotic metabolism are preferentially situated in the perivenous zone.

NO SE SI FALTE MAS AQUI!!

IV. ORGAN IT FORMS

• Anatomy

Hepatocytes are the predominant cell type in the liver. An estimated 80% of the liver mass is made of these cells. The hepatocytes are round in shape containing a nucleus and an abundance of cellular organelles associated with metabolic and secretory functions.

Organelles include endoplasmic reticulum (smooth and rough) and Golgi apparatus for secretory functions. Also there are high numbers of mitochondria to provide energy to support the many metabolic functions on the liver.

Some of the hepatocytes lie adjacent to endothelial cells which form the walls of the sinusoids. These two cell types are separated by small space called the space of Disse.

http://physrev.physiology.org/content/69/3/708.short

http://www.nottingham.ac.uk/nmp/sonet/rlos/bioproc/liveranatomy/5.html

• Physiology

Liver Function

The liver receives 30% of the resting cardiac output and acts as a giant chemical processing plant in the body. These chemical reactions, called metabolism, are central in the regulation of body homeostasis.

The liver cells, called hepatocytes, contain thousands of enzymes essential to perform vital metabolic functions. They are supermodels in the world of cellular metabolism.

The liver metabolises both beneficial and harmful substances. It stores nutrients and other useful substances, as well as detoxifying or breaking down harmful compounds. These can be then excreted from the body in bile via the liver; in urine via the kidney, or by other means.

• IMPORTANCE

One important function hepatocytes are responsible for is PROTEIN SYNTHESIS and storage. These cells produce and store a wide range of proteins for use by the body. In addition, they metabolize carbohydrates and lipids ingested by the body. Another function of this cell is to make and secrete bile. Bile leaves the liver along the bile duct and plays a role in digestion.

V. Types of disorders or disease

The liver is the largest internal organ in the human body. Some of the liver’s functions are:

• metabolize most of the nutrients that are absorbed by the intestine

• store nutrients

• produce proteins

• detoxify blood by removing medications, alcohol, and potentially harmful chemicals from the bloodstream and treating them chemically so they can be excreted by digestive or urinary systems.

The liver is also considered as a gland, because besides its many functions, it makes and secretes bile. The liver is located in the upper right portion of the abdomen protected by the rib cage.

The liver is protected from diseases mainly in two ways. First, it can regenerate itself by replacing or repairing the injured tissue. Second, the liver has many cell units responsible for the same task, so if one area is injured, other cells will perform the functions of the injured section indefinitely or until the damage has been repaired.

Liver disease is any disturbance of liver function that causes illness. The liver is responsible for many really important functions within the body and if it becomes diseased or injured, the loss of those functions can cause a lot damage to the body. Liver disease is also called hepatic disease.

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