Digestion and Absorption of Proteins

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion.
Protein digestion occurs in the stomach and duodenum in which 3 main enzymes, pepsin secreted by the stomach and trypsin and chymotrypsin secreted by the pancreas, break down food proteins into polypeptides that are then broken down by various exopeptidases and dipeptidases into amino acids. The digestive enzymes however are mostly secreted as their inactive precursors, the zymogens. For example, trypsin is secreted by pancreas in the form of trypsinogen, which is activated in the duodenum by enterokinase to form trypsin. Trypsin then cleaves proteins to smaller polypeptides.
here are at least five hormones that aid and regulate the digestive system in mammals. There are variations across the vertebrates, as for instance in birds. Arrangements are complex and additional details are regularly discovered. Connections to metabolic control (largely the glucose-insulin system) have been uncovered.
Gastrin - is in the stomach and stimulates the gastric glands to secrete pepsinogen (an inactive form of the enzyme pepsin) and hydrochloric acid. Secretion of gastrin is stimulated by food arriving in stomach. The secretion is inhibited by low pH.
Secretin - is in the duodenum and signals the secretion of sodium bicarbonate in the pancreas and it stimulates the bile secretion in the liver. This hormone responds to the acidity of the chyme.
Cholecystokinin (CCK) - is in the duodenum and stimulates the release of digestive enzymes in the pancreas and stimulates the emptying of bile in the gall bladder. This hormone is secreted in response to fat in chyme.
Gastric inhibitory peptide (GIP) - is in the duodenum and decreases the stomach churning in turn slowing the emptying in the stomach. Another function is to induce insulin secretion.
Motilin - is in the duodenum and increases the migrating myoelectric complex component of gastrointestinal motility and stimulates the production of pepsin.

[@nifat5203]

Very helpful lectures
Much obliged Sir

[@BhagyashreeURao]

just want to say, thank you, thank you very much. your videos really helped when I had to learn a concept quickly. thank you so much! you got me through my bachelor's.

[@hussainbiology]

thanks for appreciation...Glad it helps...

[@shinn-tyanwu4155]

Outstanding presentation thanks 😊😊

[@hussainbiology]

So nice of you

[@michaeleisenberg7867]

Shabir, This was a magnum opus! Solid work!! Thank you. 💖💝💪👏👏👏 I love how you went into the active sites.
I had to look up first vertebrate. A jawless fish or sea worm. The Cambrian explosion 💣! It took maybe 50 to 100 Ma for the blobs from the Ediacaran to evolve a digestive tract in the Cambrian. Evolution!

[@hussainbiology]

thanks Dr Mike for appreciating my work... Lots of love

[@altgrfin]

شكرا

[@michaeleisenberg7867]

Hello Shabir, These last three videos are making me hungry. 🍌🥞🍛🍦

[@SufianaShahzad]

Thank you for the video comprensible

[@hussainbiology]

Glad it was helpful!

[@sitaraumar2333]

Mind blowing Ma Sha Allah ❤

[@hussainbiology]

thanks Sitara for appreciation...

[@janhvi__2944]

Nice explained....
Thanku sir for makes easy steps

[@hussainbiology]

thanks Janhvi for appreciation..Glad it helps ✌️

[@sidrahaider556]

Very well explained..

[@hussainbiology]

thanks for appreciation

[@MirriamMercy]

I like the video but improve on the speed

[@zubairahmaddar2453]

❤❤❤❤😊

[@user-lh8nv3ug8t]

❤

[@hussainbiology]

thanks...Keep sharing and supporting

[@amashagunarathne1628]

Are you sure that aminopeptidase breaks the peptide chain at carboxyl end and not at amino end?????? My lecture notes say it breaks the peptide chain at amino end.

[@DrareebakhanMkd]

N terminal write answer

[@user-sl6fr9uh3t]

Sir plz Do videos on part c for csir plzzzzzzzzzzz sir please please.

[@nursechiomambamara9702]

Is this not too much to learn😔😔😭😭why not summarize 😢

[@DEMIGOD-sg7jh]

PLEASE IN HINDI TOO😅