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# CHAPTER 21. PATHOPHYSIOLOGY OF THE DIGESTIVE SYSTEM The main function of the gastrointestinal system is to break down nutrients into small particles and absorb them into the body. This function is carried out through mechanical processes (grinding and transporting food) and the action of digestiv...

# CHAPTER 21. PATHOPHYSIOLOGY OF THE DIGESTIVE SYSTEM The main function of the gastrointestinal system is to break down nutrients into small particles and absorb them into the body. This function is carried out through mechanical processes (grinding and transporting food) and the action of digestive juices. The digestive system has hormone-producing glands and nerve plexuses (Auerbach and Meissner). Generally, the digestive system functions under the control of the autonomic nervous system. Normally, activation of the sympathetic nervous system slows the motor and secretory functions of the gastrointestinal system, while activation of the parasympathetic nervous system increases them. Insufficiency of digestion is understood as a violation of digestion and absorption of nutrients. It can be divided into two parts: general (total) and selective (partial). With general insufficiency, the digestion of all nutrients is affected; with selective insufficiency, the digestion of individual nutrients is affected. The classification of digestive system disorders is based on various principles: * **Anatomical:** Disorders located in the oral cavity, stomach, and intestines. * **Clinical course:** Acute or chronic. * **Etiology:** Congenital or acquired. * **Pathophysiological principle:** Disorders of motility, secretion, absorption, and other functions. Disorders in one part of the digestive system can impact other parts. ## 21.1 General Etiology of Diseases of the Digestive System Various etiological factors contribute to digestive system diseases: 1. **Alimentary factors:** Intake of dry, rough, hot, cold, or poor quality food. 2. **Physical factors:** Ionizing radiation. 3. **Chemical factors:** Salts of heavy metals, poisons. 4. **Biological factors:** Causative agents of typhoid fever, dysentery, helminth infestations, *Helicobacter pylori*. 5. **Mental factors:** Negative emotions, stress. 6. **Social factors:** Bad habits. 7. **Congenital anomalies of the digestive tract.** 8. **Tumors, endocrinopathies, postoperative conditions.** Additionally, pathology in other body systems (blood circulation, liver, kidneys, endocrine glands), changes in substance levels (hormones, prostaglandins, peptides, biogenic amines), and neurogenic influences (sympathetic and parasympathetic nervous system) can affect the digestive system. Factors that influence the effect of etiological factors leading to digestive system pathology include individual reactivity, gender, age, and hereditary predisposition.