Hello everybody,how are you all? Hope you all are doing well and i am too.i studied embryology and want to share some knowledge with you.To understand embryology proper orientation and is required and imagination is must.i would like to tell about how the liver is developed.

Our body is made up of 3 germ layers and we know that from childhood that they are Ectoderm,Mesoderm and Endoderm.we have gastrointestinal tract and it is Endodermal in origin.why we have to know this? For this question we have to see the development of liver to find something which is interesting.

Lets see ,first see this schematic diagram of saggital view embryo for our easy understanding, outer black line is Ectoderm(it give some structures) and the blue line that drawn represents foregut,midgut and hindgut and they are endodermal in origin.these foregut,midgut and hindgut forms into gastrointestinal tract the oesophagus,stomach,duodenum,jejunum,ileum and caecum.
The cloaca will become anus.

DEVELOPMENT OF LIVER

We have to take a section at foregut, lets take transverse section at foregut and now look from anteriorly or from front(red arrow mark).

Hope u understand the orientation.now,how the embryo looks like from anterior view.see this image

Black outer line represents ectoderm.
The blue color represnts gut.
The red colour one is peritoneal layers and they are mesodermal in origin.there are two peritoneal layers one is parietal peritoneum and another is visceral peritoneum.visceral peritoneum means which covers the viscera(organs) like liver,gut etc in abdomen.

When these two layers meet they form mesentery one is ventral mesentery and another one dorsal mesentery.dorsal represents posterior side(backside) and ventral represent anterior side(front side) so we have to imagine it with our body.

Now,how the liver is formed? Lets take a section at 2nd part of duodenum of gut.

From 2nd part of duodenum,cells will divide and they grow anteriorly and evaginate and pass throught the ventral mesentary and forms a bud called HEPATIC BUD.so now we came to know that hepatic bud comes from 2nd part of duodenum.See the diagram

This hepatic bud grow and gets separated from 2nd part of duodenum and then it gets developed into liver.

We can say now that liver is originated from gut(2nd part of duodenum).so it is Endodermal in origin. One thing we clearly understood.but kuppfer cells and stroma of liver is developed from septum transversum which is Mesodermal in origin.heoatocytes and biliary apparatus are formed from hepatic bud(endodermal in origin).

We also understood that liver is formed in Ventral mesentery.

The ventral mesentery which is present anterior to liver forms the Falciform ligament.
The ventral mesentery which is present between liver and 2nd part of duodenum(gut) forms the Lesser omentum

Lesser omentum has two parts -

• Hepatogastric ligament
• Hepatoduodenal ligament
  See the below image to understand

Image source

So,this is how liver gets developed.i made a gif.just look it at once and enjoy.

Hope you learned how the liver is developed.In the next post you will learn how the spleen and pancreas are developed.

REFERENCES -

• Inderbir Singh's Human Embryology - 11th edition page - 192
• Langman's Medical Embryology 14th edition page - 225,236
  Thanks for reading my post.
• Grays Anatomy:The anatomical Basis of clinical Practice,41st Edition page 1048

With regards,