Bilirubin Metabolism

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[armandohasudungan]

🧠 TEST YOUR KNOWLEDGE FROM THIS LECTURE! ✅

[nazgulu]

Dear Armando, I am a chief physician and manager of an emergency clinic in Norway. In 2 weeks I am spending a whole day teaching our staff in causes of abdominal pain and symptoms from diseases causing abdominal pain. I needed a quick memory refreshener on the complete bilirubin metabolism to explain the aspects of jaundice and saw this.. This video is just simply brilliant! Thank you so much.

[shilpamankar]

I am doctor passed out 15yr back.loved ur drawing.needed clarity and revision.so grateful for this.love from India.

[oreman]

as a MS1 I truly appreciate learning this stuff and then coming and watching your videos which allows me finally see how it all comes together and keeps the bigger picture in mind.

[alexmilevskyy]

You do an amazing job sir! The graphics and explanations are terrific! Perfect marriage between science and art :)

[RJay]

This was incredibly helpful, and presented in a much easier way to follow than in class. Thank you very much!

[Tanayanar]

You. Are. Awesome.
I used to mug this up every year, all theough four years of medschool. Finally UNDERSTANDING it in my final year. Thank you so much. You have a gift!

[hugodesrosiers-plaisance]

I always watch your videos to review material before tests or quizzes, when I'm too tired to read or just don't feel like reading, or just want another take on material that's already familiar to me. You sometimes put things just a bit differently than my teachers do and that can make the material stick to my head much more easily. Your channel is an incredibly valuable complement to my teachers and their class notes.

[usmanahmed]

Sir you got amazing skills, mind and a great method of teaching ! I am a Med student I found your tutorials very useful specially when Im studying guyton for physio...

[lenethlopez]

You make things so simple. It took me 3 hrs to understand things by myself. What a life saver

[smech]

What an explanation. Even a illiterate can understand easily. The uses of different colour and explanations of everything made it so easy to understand. I really appreciate your work from heart and mind. Thank you for sharing such an awesome video.

[Ventus]

So artistic, very well explained and enjoyable to hear too. Thank you so much it was very helpful

[jaybee]

Thank you Armando! After years of reading text books I finally understand jaundice with your animation.

[oguzhanpolat]

I was just spending hours to understand bilirubin metabolism, until I saw this video. You do great job.

[JJAngleton]

Very nice video. Just for the sake of some more details, please allow me to further specialise and sum up:

RBC when denaturing are taken up by Macrophages located predominantly in the Cords of Billroth in spleen, bone marrow and liver. It is an important point to understand that RBC normally do not undergo intravascular lysis.

Billirubin is a breakdown product from Hb. Heme Oxygenase cleaves Heme (the Porphyrin part) into Verdoglobin (if Heme is still attached) or Billiverdin which will finally be reduced by Billiverdin-Reductase into Billirubin. Oppositely, Fe is recycled by Apoferritin in Ferritin and complexes to Hemosiderin.

Note: This function of Hb breakdown by HO can occur in virtually every cell and is NOT liver-specific.

In liver, hepatocytes release Billirubin-binding-proteins in the circularly system. Those newly formed complexes of are too large large and cannot diffuse back to microcirculatory system.

Note: Up to now, we are still talking about unconjungated (indirect) Billirubin which is not water soluble due to intra molecular hydrogen bonds and thus cannot be filtered into urine.

This form, still in the circulatory system, is highly toxic, but now trapped. Trough the hepatic artery and the portal system it goes to liver which will take it up. Within hepatic sinusoids, it enters the endoplasmic reticulum and will be conjugated with Glucuronic Acid by GT (Glucuronyltransferase). It became now highly polar and trapped within the hepatocytes. On the canalicular side of the hepatocytes are active transporters that will drain it into biliary ducts. Next it will be concentrated in bile and finally released into GIT. Microbes and enzymes will convert it now into Urobilinogen. Some is reabsorbed and goes back into enterohepatic cycle and since it is highly polar and unbound, it will be renally filtered and passed out by the urinary tract.

However, the largest part will remain in the bowl and be converted by bacteria into Stercobilinogen which will be oxidized into Stercobilin that makes the dark color of feces.

[nitinkulkarni]

Excellent tutorial! Simple language makes it easy to understand the process.
Thank you.
- Nitin

[GravisTKD]

As someone who has been diagnosed with Gilbert Syndrome (elevated blood concentrations of unconjugated bilirubin), this is a great video to see.  I love what you're doing!

[mygoldentruth]

At 2:28, about iron: it is transported by transferrin after ceruloplasmin (ferroxidase) oxidizes the ferrous ion (Fe++) to its ferric form (Fe+++). This is because transferrin is able to transport up to two iron ions only when they are in a ferric state. Otherwise iron could be lost through urine, since it's able to pass glomerular basement membrane (which is, yes, charged negatively).

If I made any mistake, please point it out. Have a nice day, guys!

[trdzika]

you are such a good teacher.well presented.greetings from Zimbabwe

[sagarshrestha]

I am veterinary Student and it is very helpful, clear doubts and gives the image in mind which is remembering in lifetime❤