Welcome to the Christmas season- PhD students are hanging up dusty tinsel, everyone’s rushing to finish experiments and there’s a welcome increase of cakes being circulated around the office.

Somewhere within this muddled environment you’ll find Student Scrooge.

Student Scrooge is the student who has lost passion in their project and feels that it’s more likely for the ghost of Christmas past to visit them than to be able to find a significant difference within their data.

Now you might think that a Christmas break from the lab might be the healthy treatment of choice for Student Scrooge, but according to Hippocrates from Ancient Greece, they might benefit more from having a liver transplant from Tiny Tim.

In fact before the birth of modern medicine, people used to associate the feelings of cowardice, pessimism and lack of passion to defects in the liver. In the past, the liver was regarded as almost a holy organ. Imsety, an Ancient Egyptian God had the duty to protect the liver of the dead. In old Islamic Medicine, it was written that there were three types of spirit (natural, vital and psychic), and that the ‘natural spirit’ was contained within the liver.

It seems however, that the romanticised associations of the liver are now long gone, and when we think of the liver now, we think of a boring triangular organ. Most people don’t even know where it is in the body (in the ribcage). Yet even the general gross morphology of the liver holds some interesting facts; e.g, the falciform ligament, (which separates the two lobes of the liver), originated from your umbilical cord. All vertebrates have two lobed livers, with the exception of snakes- who have cigar shaped livers.

Probably the best known (and most appreciated) function of the liver among students is its ability to detoxify of toxins from alcohol, but actually the liver has a remarkable amount of other functions.

For starters, the liver is responsible for making enzymes and proteins for nearly every single enzymatic reaction in the body. This includes the production of blood clotting factors. Hence the liver is what prevents an endless stream of blood pouring from your finger each time you get a paper cut.

In addition to this, the liver is a very important organ for the immune system. Within the sinusoids of the liver there are Kupffer cells, a type of macrophage (a pacman like immune cell) that constitutes to 80–90% of the tissue macrophages present in the body. These play a vital role in fighting infections, in particular to those arising from the bowel.

8% of our body weight is due to the glycogen stored within our liver. Not only does the liver store glycogen, but it also stores iron, copper, and vitamins. So effective is it at doing this for polar bears, that if you were to eat a polar bear’s liver you would die almost instantly of acute hypervitaminosis- essentially a vitamin overload.

Perhaps the most remarkable feature of the liver is that as little as 25% of a liver can ‘regenerate’ into a whole liver. This makes the liver the only internal human organ capable of natural regeneration. In humans and other mammals, this is mainly a compensatory ‘regeneration’ in that only the mass rather than the shape of the liver is regenerated; however, in fish both the liver size and shape can be completely regenerated.

The liver is definitely one of the toughest organs in the body, but this can also problematic as it means that liver diseases such as cirrhosis rarely show any symptoms until that person has lost a lot of liver function.

 

So that brings me onto the final important point of this piece:

Spare a little thought for your liver this Christmas.

 

I hope you all have a lovely Christmas break 🙂

 

Written by Seran Hakki