Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

Which digestive organ is primarily responsible for chemical digestion and absorption of food?

1. Large intestine

2. Stomach

3. Small intestine

4. Liver

The correct answer is: Small intestine

The small intestine is the primary organ responsible for chemical digestion and absorption of nutrients from food. It is divided into three sections: the duodenum, jejunum, and ileum. In the small intestine, enzymes from the pancreas and bile from the liver play a crucial role in breaking down food particles. The lining of the small intestine has specialized structures called villi and microvilli that significantly increase the surface area for absorption, allowing for efficient uptake of nutrients into the bloodstream. Chemical digestion continues here after initial processes in the mouth and stomach, breaking complex molecules into simpler ones that can be absorbed. Virtually all nutrient absorption, including carbohydrates, proteins, fats, vitamins, and minerals, occurs in the small intestine, making it vital for maintaining overall health and energy levels in the body.