GASTROINTESTINAL PHYSIOLOGY

Question 1

What are the four major activities of the gastrointestinal (GI) tract?

Answer 1

Motility, secretions, digestion (mechanical and chemical), and absorption.

Question 2

What is the role of the enteric nervous system?

Answer 2

It regulates GI functions independently, processing sensory input and coordinating motor and secretory output.

Question 3

How do the extrinsic and intrinsic nervous systems contribute to GI function?

Answer 3

The extrinsic system (autonomic) modulates GI activity; the intrinsic (enteric) system directly controls local reflexes and motility.

Question 4

What are key anatomical and histological features of the GI tract?

Answer 4

The GI tract includes specialized regions (mouth to anus) with mucosal layers, muscularis, and nerve plexuses suited for digestion and absorption.

Question 5

Where does most digestion and absorption occur in the GI tract?

Answer 5

In the small intestine, supported by enzymes from the pancreas and bile from the liver.

Question 6

How is digestion of macronutrients achieved?

Answer 6

Proteins, carbohydrates, and fats are broken down by enzymes in the lumen, brush border, and cytosol into absorbable units.