Digestive System: Organs, Functions and Common Disorders

Digestion

Digestion is the set of mechanical and chemical processes that transform food into substances the body can absorb. Nutrients, water, and minerals are taken in through food and drink (intake). No other special cells, absorption, or approximation take place. Nutrition is involuntary, and the body must transfer and use the nutrients to supply cells, eliminating the substances that cannot be absorbed.

Digestive Tube

1. Pharynx: Food passes through the pharynx. Difficulty in swallowing (dysphagia) and painful swallowing (odynophagia) may occur here.
2. Esophagus: A muscular tube that carries food from the pharynx to the stomach. Involuntary contractions and peristalsis move the bolus downward. The diaphragm is crossed as the esophagus enters the abdomen.
3. Stomach: Absorbs alcohol, water, and some drugs. The cardia and pylorus sphincters control the entry and exit of food. Muscular contractions mix the bolus with gastric juice, converting it into a liquid form called chyme.
4. Small intestine: Chyme is moved along by peristalsis for digestion and absorption. It is divided into three parts: the duodenum (receives hepatic and pancreatic secretions), the jejunum, and the ileum.
5. Large intestine: Begins at the ileocecal valve and includes the cecum (with the appendix) and the colon. The colon has an ascending portion, a transverse portion, a descending portion, the sigmoid colon, and the rectum, which forms the final straight segment.
   Function: Absorbs water and salts, forms and stores feces, and houses intestinal flora. Its contents move without irritating the mucosa.
6. Anus: The sphincters open and close voluntarily and involuntarily to expel waste.

Digestive Glands

1. Liver (located in the upper right abdomen). It receives blood from the hepatic artery (oxygenated blood) and the portal vein (nutrient-rich blood).
   Functions: Secretes bile, processes nutrients and metabolizes them, stores glycogen, vitamins, and iron, synthesizes vitamin B12 and plasma proteins, and detoxifies blood-borne substances that the body does not incorporate (alcohol, drugs, etc.).
2. Gallbladder and bile ducts: Store and release bile.
3. Pancreas: Has two functions: endocrine (produces hormones such as insulin and glucagon) and exocrine (produces digestive enzymes).

Feces

Feces are the waste product of digestion. Their characteristics vary:

• Frequency: Varies from person to person. Changes that persist for more than three days, such as diarrhea or constipation, should be evaluated.
• Quantity: Larger amounts are often linked to a diet high in vegetables and low in fiber, or to a diet without fruit.
• Consistency: Depends on the water content.
• Color and smell: Normally brown. Black, tarry stools may indicate bleeding in the upper digestive tract. Pale, clay-colored stools may indicate bile duct obstruction. Greasy, bulky stools with a foul odor may indicate steatorrhea (excess fat).

Gastrointestinal Disorders

Inflammation of the gastric mucosa (gastritis) may be acute or chronic and ranges from mild to severe. Symptoms include nausea, vomiting, and pain. Severe vomiting or vomiting blood requires urgent medical care. Treatment includes avoiding irritating foods and following a bland diet.

Risk Factors

• Sedentary lifestyle
• Age
• Sex
• Causes: Excessive consumption of chlorides, genetic inheritance, anxiety, endocrine disorders, and boredom.

Possible Complications

Joint pain, muscle pain, fatigue, and dyslipidemia (abnormal blood fat levels).