Hepatocytes: What They Are And What Functions They Have In The Human Body
The liver is an organ of utmost importance in our species and in the rest of vertebrates. This structure, in humans, weighs about 1,800 grams, that is, 2% of the body mass of an adult individual.
With such a small weight, the liver is capable of receiving 1,500 milliliters of blood per minute, a value only surpassed by the heart (the figure amounts to 5,000 milliliters per minute). The functions of this organ, as we will see in later lines, are essential for the physiological well-being of the organism and the persistence of the species over time.
We all know the importance of the liver, but do you know what functional units build it? Today we address the world of hepatocytes, the cells that predominate in liver tissue and they shape this organ essential for life.
First of all, it is of special interest to know that Hepatocytes make up 80% of the liver and form its parenchyma, that is, the tissue specialized in the functions that define the organ. Before entering into morphological and functional issues, we review the functions of the liver (and therefore, hepatocytes) in a few lines. Go for it:
In general, all of these functions and many more can be summarized in a series of key terms: synthesis, storage, metabolism and detoxification Of course, we are facing one of the most multifunctional and essential organs in the entire body.
Hepatocyte morphology
Once we have described the functions of the liver in a general way and we have shown you some interesting statistics to frame it from a physiological point of view, it is time to get a scalpel and a microscope, in order to analyze the characteristic morphology of the hepatocytes. .
First of all, it is interesting to know that These cells are polyhedral or prismatic in nature, that is, they have a geometric shape with several faces (usually 6) These individual structures are observed with an optical microscope, as they are large, about 20-40 micrometers in diameter.
It is also characteristic of this cell type to present two spherical nuclei, which occupy 20 to 25% of the cell. Furthermore, these are tetraploid, that is, they have 4 sets of chromosomes enclosed in the nucleus (instead of 2, as is the case with most cells in the human body, which are diploid in nature).
As far as the cytoplasm is concerned (part of the cell that surrounds the nucleus and is delimited by the outer membrane), the fact that stands out is that has inclusions of glycogen and fat a fact that is clearly justified by the storage function performed by the liver.
It is also worth noting that abundant small mitochondria are found in this medium (about 800 to 1,000 per cell), which occupies up to 25% of the liver cell surface in mammals. Without a doubt, this shows the great metabolic expense and work that hepatocytes must face.
How are they organized?
Without going fully into complex histological terms, we can say that These cell types are polarized, that is, they have two poles, one sinusoidal and the other canalicular The sinusoids are channels through which blood flows from the portal spaces to the hepatic venule, while the bile canaliculi allow the excretion and transport of bile from the hepatocytes. Thus, this polarity is essential for the correct functioning of the cells that concern us here.
Unlike other epithelial cells, this specialized type is not anchored to a basement membrane, but rather the cell is surrounded by an extracellular matrix secreted by the hepatocyte itself. These “spaces” facilitate the exchange with the sinusoidal channels already mentioned, since through them, these cells capture water, electrolytes, organic solutes dissolved in the blood plasma (such as bile acids) or drugs, which are metabolized and eliminated from of the canalicular or biliary pole. Thanks to this little histological lesson we can understand how the liver is capable of purifying the blood.
It should be noted that, once the bile is produced in the hepatocytes, it flows into the intrahepatic bile ducts, which ultimately meet in a common hepatic duct, which takes the substance to the gallbladder, where it is stored. As in many other transport structures, we must imagine this series of channels and tubes as a tree: the cells could be the analogue of the leaves, and each of the individual branches, the small ducts that lead to the main trunk, in this case the common hepatic duct.
Functions of hepatocytes
We abandon the histological subject, since there are some complex concepts to cover that, unfortunately, would somewhat escape the competencies of this space. Even so, we believe that this previous summary allows us to get a general idea of the functioning and disposition of hepatocytes.
As you may have guessed previously, the main function of this cell type is to metabolize substances that are a product of the digestion of food. This is possible because The hepatocytes are supplied (at the sinusoidal pole) by the portal veins, which collect the compounds resulting from the digestion of food at the intestinal level. This involves, at the cellular level, the synthesis and storage of proteins, carbohydrate metabolism, lipid metabolism and gluconeogenesis, that is, the formation of glucose from precursors that are not carbohydrates (such as lactate, pyruvate or glycerol).
On the other hand, and as we have already said in previous lines, these cells They have a catabolic function (degradation) of drugs and other toxic compounds and synthesis and transport of bile to the gallbladder an essential liquid in the digestion process.
The importance of hepatocytes and the liver
You only need to see a patient with jaundice to realize the enormous impact that liver failure can have on the body. Bilirubin is a yellowish pigment that results from the breakdown of hemoglobin in recycled red blood cells This substance is conjugated in the liver and becomes part of bile and is then excreted into the duodenum, which gives color to the stool.
When hepatocytes are destroyed or their ducts fail, an increase in bilirubin is generated at the tissue level, which gives the patient the characteristic yellow skin tone. This symptom is usually accompanied by swollen legs and abdomen, changes in the color of feces and urine and a great ease in showing superficial bruises.
Addictions such as chronic alcoholism can favor the appearance of all these signs, since Cirrhosis is nothing more than the replacement of natural liver tissue with fibrous scar tissue Of course, the advice and considerations to avoid liver discomfort are self-explanatory: the more we expose our body to harmful substances, the more the purifying system that allows us to be alive will suffer.
Summary
Who would have told us that such a specific cell type would give us so much to talk about? The hepatocytes Not only are they the essential component of the liver at a structural level, but they synthesize bile, metabolize products from the diet and are capable of degrading drugs and other harmful substances present in the bloodstream.
We cannot end this space without making a sad but necessary mention of alcoholism in the world, since the World Health Organization (WHO) estimates that more than 3 million people died in 2016 due to the harmful consumption of alcohol, which represents one in every 20 deaths worldwide. To a certain extent, keeping our liver healthy is a matter of will, which is why an appropriate lifestyle can save our lives.
