GIT Physiology Chapter 1

General Principles of Gastrointestinal Function-Motility, Nervous control, and Blood Circulation

🧠 Main Functions of the Alimentary Tract

The digestive system’s job is to provide a constant supply of:

• Water
• Electrolytes
• Vitamins
• Nutrients

To do this, it performs five main tasks:

1. Movement of food through the tract (motility)
2. Secretion of digestive juices and enzymes
3. Digestion of food into absorbable molecules
4. Absorption of nutrients and water into the blood
5. Circulation and control (by nervous and hormonal systems)

🧩 Anatomy of the GI Wall (from outer to inner layer)

1. Serosa – outer covering
2. Longitudinal muscle – runs along the tract
3. Circular muscle – wraps around the tract
4. Submucosa – contains blood vessels and nerves