登录

Absorption refers to taking dietary nutrients from the intestinal lumen for transportation throughout the body. After digestion in the small intestine, carbohydrates, proteins, and fats are broken down into simpler forms. These essential macronutrients and other vital substances, such as vitamins, minerals, and water, are then prepared for absorption into the bloodstream.

Enterocytes, which are specialized polar epithelial cells, line the mucosa of the small intestinal walls. These cells possess microvilli, or tiny finger-like projections, at their apical ends, which help to increase the surface area for absorption. Tight junctions near the apical region of the lateral surface of enterocytes prevent substances from passing between the enterocytes.

As a result, substances enter an enterocyte through its apical membrane from the lumen and exit through the basolateral membrane into the interstitial fluid on the other side of the cell. Since the plasma membrane of cells is a lipid bilayer, it allows the passive absorption of nonpolar substances. On the other hand, polar substances use active transport processes driven directly or indirectly by energy.

Once the substances enter the interstitial fluid, they diffuse into the blood capillaries.

来自章节 27:

article

Now Playing

27.38 : Absorption of Nutrients

Digestive System

177 Views

article

27.1 : Major Organs of the Digestive System

Digestive System

784 Views

article

27.2 : Peritoneum

Digestive System

771 Views

article

27.3 : Histology of the Gastrointestinal (GI) Tract

Digestive System

413 Views

article

27.4 : Nerve Supply of the GI Tract

Digestive System

527 Views

article

27.5 : Regulation of the Digestive System

Digestive System

272 Views

article

27.6 : Blood Supply to the Digestive System

Digestive System

361 Views

article

27.7 : Oral Cavity

Digestive System

239 Views

article

27.8 : Tongue

Digestive System

292 Views

article

27.9 : Salivary Glands and Saliva

Digestive System

259 Views

article

27.10 : Teeth

Digestive System

228 Views

article

27.11 : Tooth Anatomy

Digestive System

237 Views

article

27.12 : Esophagus

Digestive System

216 Views

article

27.13 : Deglutition

Digestive System

1.1K Views

article

27.14 : Gross Anatomy of the Stomach

Digestive System

268 Views

See More

JoVE Logo

政策

使用条款

隐私

科研

教育

关于 JoVE

版权所属 © 2025 MyJoVE 公司版权所有,本公司不涉及任何医疗业务和医疗服务。