Intestines
The intestine is the longest section of the digestive tract, the total length of which reaches 7–8 meters. Here food digestion is completed, nutrients are absorbed and feces are formed.
Small intestine
The small intestine is 5–6 meters long divided into three sections:
Dodenum (duodenum) is the shortest but most important section (25–30 cm). The ducts of the pancreas and gallbladder open here. Here, the acidic contents of the stomach are neutralized by bicarbonates, and fats are emulsified by bile.
Jejunum (jejunum) and ileum (ileum) are the main sections of absorption. Their mucosa forms circular folds covered with villi 0.5–1 mm high. Each villus contains a capillary network and a lymphatic vessel. On the surface of the villi there are microvilli, increasing the suction area to 30 m².
The small intestine absorbs: amino acids, monosaccharides, fatty acids, vitamins, minerals and water.
Large intestine
The colon is 1.5–2 meters long and includes:
- Caecum with appendix (appendix)
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
- Rectum
Main functions: absorption of water (up to 1.5 liters per day) and electrolytes, formation and promotion of feces.
Microbiome
The gut is home to 38 trillion bacteria—more than the body's own cells. Intestinal microflora:
- Synthesizes vitamins K and group B
- Breaks down plant fiber
- Competes with pathogenic bacteria
- Participates in the formation of immunity
Disturbances in the composition of the microbiome (dysbiosis) have been linked to allergies, obesity, inflammatory bowel disease, and even mood disorders.
Clinical significance
Appendicitis - inflammation of the appendix - is the most common surgical disease of the abdominal cavity. The pain begins in the epigastrium, then moves to the right iliac region - the classic Kocher sign. Knowledge of intestinal anatomy is critical for surgeons when performing resections and creating anastomoses.
The sections of the small and large intestine, their relative positions and connections with other abdominal organs can be conveniently studied in 3D atlas Humio - scale and rotate the model for a full overview.