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Hepatocytes

The cells comprising the liver parenchyma, the hepatocytes, are its primary functional units. Each individual cell has the capacity for all functions. As a group, the hepatocytes perform a vast array of tasks, all of which are necessary for the maintenance of physiologic homeostasis.

In the normal adult liver, it has been estimated that there are about 250 billion hepatocytes (1:xxix). Indeed, the liver is the largest visceral organ in mammals; in man, its weight is approximately 1.5 kilograms (2:8).

The development of the liver parenchyma starts from entodermal cells which grow into the mesenchyma of the septum transversum (2:8). The organ and its hepatocytes generally perform two major actions. At one end of the spectrum, the liver serves an ingestive function; at the other end, its secretory functions are exerted.

Hepatocytes comprise 80% of the livers volume and 60% of its total cell number (2:10). In histological sections, the parenchymal cells appear irregularly polygonal and form a walllike structure (muralium) of anastomosing plates. These plates tend to be onecellthick structures, although twocellthick plates also occur. The plates are bent to form a lacunar meshwork. Within this meshwork, the sinusoids lead the mixed blood of the hepatic artery and portal vein into the "labrinthus hepatis" (2:1011). In addition to plates and sinusoids, this labyrinth also contains bile canaliculi (1:xxiv). These canaliculi are about 1 micrometer in diameter; their walls are made up of adjacent hepatocytes. Together they form a kind of chickenwirelike network within the hepatocyte plates. The bile canaliculi are the primary source of bile released into the duodenum.

These canaliculi are separated from the perisinusoidal and sinusoidal areas by junctional complexes of tight junctions and desmosomes. Hepatocyte gap junctions are generally considered impermeable. They do, however, allow for some communic

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Hepatocytes. (1969, December 31). In LotsofEssays.com. Retrieved 11:25, March 29, 2024, from https://www.lotsofessays.com/viewpaper/1684071.html