Electrolytes are essential minerals and ions primarily obtained from the diet and absorbed through the gastrointestinal tract. Most electrolytes are absorbed in the small intestine. While the absorption of iron and calcium primarily occurs in the duodenum, calcium is also absorbed in the jejunum and ileum. In these regions, passive diffusion contributes to its absorption alongside active transport mechanisms in the duodenum. These ions can exit the enterocytes through specialized active transporters or passive movement along a concentration gradient to enter the interstitial fluid.

When sodium ions enter the enterocytes, the basolateral sodium-potassium pumps actively transport them into the interstitial fluid. Chloride ions typically follow these sodium ions, while potassium ions use facilitated diffusion to cross the intestinal mucosa.

The small intestine absorbs dietary vitamins, while gut bacteria absorb K and B vitamins in the large intestine. Fat-soluble vitamins A, D, E, and K become a part of micelles for absorption with dietary fats. Water-soluble vitamins such as B and C are primarily absorbed through passive diffusion. However, some exceptions exist; for example, vitamin B12 requires an intrinsic factor for absorption in the ileum, utilizing a receptor-mediated endocytosis mechanism rather than passive diffusion.

Lastly, water is absorbed through osmosis, moving from a region of lower solute concentration to a higher solute concentration across the cell membrane.

Из главы 28:

article

Now Playing

28.13 : Mineral, Vitamin and Water Absorption

Absorption of Nutrients

71 Просмотры

article

28.1 : Углеводы: пищевые источники и потребности

Absorption of Nutrients

146 Просмотры

article

28.2 : Белки: пищевые источники и потребности

Absorption of Nutrients

115 Просмотры

article

28.3 : Липиды: пищевые источники и требования

Absorption of Nutrients

404 Просмотры

article

28.4 : Витамины

Absorption of Nutrients

69 Просмотры

article

28.5 : Минералов

Absorption of Nutrients

99 Просмотры

article

28.6 : Обзор углеводного обмена

Absorption of Nutrients

114 Просмотры

article

28.7 : Обзор белкового обмена

Absorption of Nutrients

126 Просмотры

article

28.8 : Обзор липидного обмена

Absorption of Nutrients

429 Просмотры

article

28.9 : Холестерин: значение и регулирование

Absorption of Nutrients

368 Просмотры

article

28.10 : Усвоение углеводов

Absorption of Nutrients

75 Просмотры

article

28.11 : Усвоение белка

Absorption of Nutrients

35 Просмотры

article

28.12 : Абсорбция липидов

Absorption of Nutrients

200 Просмотры

article

28.14 : Метаболические состояния организма: абсорбционное состояние

Absorption of Nutrients

550 Просмотры

article

28.15 : Метаболические состояния организма: постабсорбционное состояние

Absorption of Nutrients

69 Просмотры

See More

JoVE Logo

Исследования

Образование

О JoVE

Авторские права © 2025 MyJoVE Corporation. Все права защищены