Carbohydrate Absorption| Part 4 Carbohydrate Foundations | Macronutrients Lecture 50
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3 سال پیش
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Getting carbohydrates into our body
Getting carbohydrates into our body requires absorption of monosaccharides across both the luminal side and basolateral sides of intestinal cells. Subscribe to Nourishable at nourishable
This video is part 4 of the Carbohydrate Foundations module within a lecture series on the nutrition science of macronutrients.
Carbohydrate Foundations Lecture playlist: Playlist
Macronutrients Lecture playlist: Macronutrients Lectures
Follow Nourishable on twitter, facebook and instagram to stay up to date on all things nutrition.
Twitter: nourishable
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Lecture Development, Hosting & Post-Production by Lara Hyde, PhD
http://www.nourishable.tv
Video Production by Robbie Hyde
chedderchowder
Opening Motion Graphics by Jay Purugganan https://www.c9studio.com/WP/
The information in this video is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this video is for general information purposes only.
References
Chapter 5 Carbohydrates in Wardlaw’s Perspectives in Nutrition, 2019 (Editors: Byrd-Bredbenner, Moe, Berning and Kelley, 11th edition)
Chapter 2 - Carbohydrates in Modern Nutrition in Health and Disease, 2014 (Editors: Ross, Caballero, Cousins, Tucker and Ziegler; 11 edition)
Images
Figures created with BioRender
The monosaccharides need to be absorbed across two layers: first across the luminal side of the enterocytes (the front door) and then across the basolateral side (the back door) to get into the blood stream. Absorption involves several different kinds of protein transporters and uses both primary and secondary active transport. Absorption relies on sodium-potassium gradients across the cell membrane. Differences in ion concentrations across the membrane is a source of potential energy. There is a higher concentration of potassium (K+) ions inside the cell and a higher concentration of sodium (Na+) outside the cell. These differences in concentration gradients are created and maintained by the sodium-potassium exchange pump. Using ATP, it will bind 2 K+ outside the cell facing the outside of the cell, bind them, flip to face inside and drop off the K+ ions. While facing the inside of the cell it will bind 3 Na+ ions, flip to face the outside and release the Na+ ions outside the cell. The use of ATP by the sodium-potassium exchange pump is a major used of energy in our basal metabolic rate. Glucose is absorbed across the luminal side with the sodium-glucose transporter 1, which is a type of secondary active transport. While facing the outside of the cell it will bind 2 Na+ ions and one glucose, then flip and spit out the sodiums and glucose inside the cell. This is relying on the gradient of sodium, sodium “wants” to travel down its concentration gradient into the cell and brings glucose along with it. Since SGLT1 is not directly using ATP but it is relying on the gradients created by the Na+/K+ exchange pump, it is secondary active transport. Both glucose and galactose are absorbed across the luminal side through SGLT1, but fructose is a bit different. To get across the basolateral side, monosaccharides use facilitated diffusion which involves the monosaccharides traveling down their concentration gradient from inside the cell to the extracellular space. To get across the membrane they use GLUT transporters. GLUT2 transports glucose and galactose across the basolateral side, and fructose uses GLUT5 for absorption across the luminal side and then also leaves the basolateral side through GLUT2.
This video is part 4 of the Carbohydrate Foundations module within a lecture series on the nutrition science of macronutrients.
Carbohydrate Foundations Lecture playlist: Playlist
Macronutrients Lecture playlist: Macronutrients Lectures
Follow Nourishable on twitter, facebook and instagram to stay up to date on all things nutrition.
Twitter: nourishable
fb.me/nourishable.tv
Instagram: nourishable
Lecture Development, Hosting & Post-Production by Lara Hyde, PhD
http://www.nourishable.tv
Video Production by Robbie Hyde
chedderchowder
Opening Motion Graphics by Jay Purugganan https://www.c9studio.com/WP/
The information in this video is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained on or available through this video is for general information purposes only.
References
Chapter 5 Carbohydrates in Wardlaw’s Perspectives in Nutrition, 2019 (Editors: Byrd-Bredbenner, Moe, Berning and Kelley, 11th edition)
Chapter 2 - Carbohydrates in Modern Nutrition in Health and Disease, 2014 (Editors: Ross, Caballero, Cousins, Tucker and Ziegler; 11 edition)
Images
Figures created with BioRender
The monosaccharides need to be absorbed across two layers: first across the luminal side of the enterocytes (the front door) and then across the basolateral side (the back door) to get into the blood stream. Absorption involves several different kinds of protein transporters and uses both primary and secondary active transport. Absorption relies on sodium-potassium gradients across the cell membrane. Differences in ion concentrations across the membrane is a source of potential energy. There is a higher concentration of potassium (K+) ions inside the cell and a higher concentration of sodium (Na+) outside the cell. These differences in concentration gradients are created and maintained by the sodium-potassium exchange pump. Using ATP, it will bind 2 K+ outside the cell facing the outside of the cell, bind them, flip to face inside and drop off the K+ ions. While facing the inside of the cell it will bind 3 Na+ ions, flip to face the outside and release the Na+ ions outside the cell. The use of ATP by the sodium-potassium exchange pump is a major used of energy in our basal metabolic rate. Glucose is absorbed across the luminal side with the sodium-glucose transporter 1, which is a type of secondary active transport. While facing the outside of the cell it will bind 2 Na+ ions and one glucose, then flip and spit out the sodiums and glucose inside the cell. This is relying on the gradient of sodium, sodium “wants” to travel down its concentration gradient into the cell and brings glucose along with it. Since SGLT1 is not directly using ATP but it is relying on the gradients created by the Na+/K+ exchange pump, it is secondary active transport. Both glucose and galactose are absorbed across the luminal side through SGLT1, but fructose is a bit different. To get across the basolateral side, monosaccharides use facilitated diffusion which involves the monosaccharides traveling down their concentration gradient from inside the cell to the extracellular space. To get across the membrane they use GLUT transporters. GLUT2 transports glucose and galactose across the basolateral side, and fructose uses GLUT5 for absorption across the luminal side and then also leaves the basolateral side through GLUT2.
3 سال پیش
در تاریخ 1400/09/15 منتشر شده
است.
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