The Intestinal Villi Explained || Absorption

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One of the functions of the small intestine is to take digested food molecules from the digestive system and transfer them into the blood, so that they can be transported to the parts of the body that need them. The digested food in the small intestine contains molecules such as glucose from the digestion of starch, amino acids from proteins, fatty acids and glycerol from lipids, as well as lots of other essential materials. These must be absorbed into the blood stream so that your body can use them.

The walls of the small intestine are lined with intestinal villi. And FYI, it’s one villus, many villi. Villus is singular, villi is plural.

The villi increase the surface area of the wall of the small intestine to maximise the rate of absorption of digested food.

Picture one flat line between points A and B, and image that material has to transfer across it. If you measure this line (the length of the surface for materials to transfer) you’ll see its 10 cm long. Now picture a line between the same points A and B, but on this new line there are finger-like projections all the way along. If you measure along the surface of this line, you’ll find it’s far longer than 10 cm. The version with the projections has a larger surface area, meaning more material can be transferred in the same amount of time.

Here’s a simplified diagram showing a single villus. Food molecules are transferred from the central space in the small intestine into the villi.

The epithelial cells of its lining have many microvilli on them. This further increases the surface area.

Villi have a good blood supply constantly flowing in and out through many blood capillaries. Most materials are transferred to the blood capillaries. There’s also a structure inside each villus called a lacteal, and the products of lipid digestion are absorbed into this part, and from there they’ll also eventually reach the blood stream at a different point.One of the functions of the small intestine is to take digested food molecules from the digestive system and transfer them into the blood, so that they can be transported to the parts of the body that need them. The digested food in the small intestine contains molecules such as glucose from the digestion of starch, amino acids from proteins, fatty acids and glycerol from lipids, as well as lots of other essential materials. These must be absorbed into the blood stream so that your body can use them.

The walls of the small intestine are lined with intestinal villi. And FYI, it’s one villus, many villi. Villus is singular, villi is plural.

The villi increase the surface area of the wall of the small intestine to maximise the rate of absorption of digested food.

Picture one flat line between points A and B, and image that material has to transfer across it. If you measure this line (the length of the surface for materials to transfer) you’ll see its 10 cm long. Now picture a line between the same points A and B, but on this new line there are finger-like projections all the way along. If you measure along the surface of this line, you’ll find it’s far longer than 10 cm. The version with the projections has a larger surface area, meaning more material can be transferred in the same amount of time.

Here’s a simplified diagram showing a single villus. Food molecules are transferred from the central space in the small intestine into the villi.

The epithelial cells of its lining have many microvilli on them. This further increases the surface area.

Villi have a good blood supply constantly flowing in and out through many blood capillaries. Most materials are transferred to the blood capillaries. There’s also a structure inside each villus called a lacteal, and the products of lipid digestion are absorbed into this part, and from there they’ll also eventually reach the blood stream at a different point.
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oh my God thank u so so much
i have a test coming up in next week and i was struggling to understand this surface area thing
but finally i got relief
well explained
straight forward into the info
Thank u so much!

shabanasafair
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Very direct, informative, 'clean', well made video! Thanks a lot for the amazing content! :)

mrjothescholar
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holy shit this is underrated, my teacher took 1 whole class to explain it while you look 2 mins

RandomMan
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Thank you so much! this was incredibly helpful.

jennalloyd
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Thank you so much for making things so easy to understand

exytsvw
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Thanks for your explanation 👍 It helps me very much

romaroy
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Surface area part, understood after 17yrs, tnx!South Africa

pumezanjokweni
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Great video!! It didn’t really cover absorption through the villi as I was hoping to see more on microvilli. Great animation though; keep up the good work!

imtired
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I came across to your YT Channel and I love your videos! It can help me explain in more detail to my students. I hope you can make videos for mitosis, meiosis and photosynthesis. Because these are the most complex topics in Biology here in my country. Looking forward to your new videos, especially the three aforementioned topics! Thank you, Alex!

carolynliezleeinso
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Made me understand better... thank you sir

julianabot
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This video helped me understand my lesson, thank you!

verina.shenouda
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Cheer~~the process or action by which one thing absorbs or is absorbed by another.

smsfffi
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thank you this really helped me with my homework

Riclardo
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Sir.. if intestine is covered with mucus then how the nutrients make it to the villi? Does food molecule have to pass through mucus and then to the villi??

Anonymous-cewx
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I might need this soon when im in year 8 or 9

Forgotten
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can you please make a video about countercurrent blood flow in vili?

bera
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I want to use this video for educational purposes. Can I?

StaySane
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Its amazing it helped alot b
Thanks English man

MuhammadMuhammad-wsro
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Thanks I could not understand it now I understood

preetigokavi
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I like everything only with sauce, now i like science

kprcht