Physiology, Nutrient Absorption

Excerpt

The gastrointestinal tract is a highly specialized organ system primarily responsible for nutrient absorption, though it has other roles. From the mouth to the anus, its length is approximately 9 meters (30 feet). The gastrointestinal tract's wide range of functions include the following:

1. Nutrient absorption - This comes after the breakdown of carbohydrates, proteins, fats, vitamins, and minerals, which are essential for energy production, growth, and cellular maintenance.

2. Egestion of waste and toxins - The process eliminates indigestible components and harmful substances from the body.

3. Maintenance of hormonal homeostasis - The gastrointestinal tract influences appetite, satiety, and metabolism.

4. Providing immunity - Immune cells line the gastrointestinal mucosa to defend against pathogens and maintain a balance between tolerance and reactivity.

5. Influencing behavior - The gastrointestinal tract is a key player in the "gut-brain axis," influencing behavior and cognitive processes.