Human Anatomy - Kotsan I. Ya. 2009

Organs of Hematopoiesis and the Immune System
Lymphoid tissue of the walls of the digestive and respiratory systems
Solitary lymphoid nodules

Solitary lymphoid nodules (noduli lymphatici solitarii) are present within the thickness of the mucosa and submucosa of the Digestive System Organs (Pharynx, Esophagus, Stomach, small and large intestines, Gallbladder), as well as the respiratory organs (Larynx, Trachea, main, lobar, and segmental Bronchi). They are located at varying distances from one another and at different depths. Frequently, the nodules lie so close to the epithelial covering that the mucosa above them rises in the form of small elevations. The number of lymphoid nodules in the mucosa of these organs is quite large. In childhood and adolescence, approximately 9 lymphoid nodules per 1 cm2 are found within the thickness of the duodenal mucosa, 18 in the ileum, 22 in the cecum, 35 in the colon, and 21 in the rectum. In the gallbladder mucosa, the number of lymphoid nodules reaches 25. Within the thickness of the laryngeal mucosa, accumulations of lymphoid tissue appear as lymphoid nodules arranged in the form of a ring (laryngeal tonsil). The greatest amount of lymphoid tissue is observed in the mucosa of the posterior surface of the epiglottis, the lateral sections of the vestibule, the laryngeal ventricles, and the aryepiglottic folds. Diffuse lymphoid tissue is also present in the mucosa of the subglottic cavity.

Development and Age-related features of solitary lymphoid nodules. Lymphoid nodules in the walls of the digestive and respiratory organs appear during the 5th–6th month of intrauterine life. In newborns and infants in their 1st year of life, the average number of nodules in the walls of the Small Intestine per 1 cm2 is 9, and in the Large Intestine—11. In the laryngeal mucosa, lymphoid nodules are also well developed in newborns. In the lower part of the larynx, nodules are formed during the 1st year of life. Within the thickness of the aryepiglottic folds, lymphoid nodules are detected in children aged 1–3 years. Germinal centers in the nodules appear shortly before birth or immediately after it.

After birth, the number of lymphoid nodules increases noticeably. By the age of 10–15 years, their number grows by 1.5–2 times compared to the neonatal period. Starting from adolescence, the number of lymphoid nodules in the mucosa of the digestive and respiratory organs gradually decreases.

Blood supply and innervation of lymphoid nodules and patches are provided by branches of Arteries and nerves that penetrate the mucosa of the corresponding organ. Venous blood from the internodular capillary networks drains through the Veins OF THE organ in whose wall the lymphoid nodules are located. Lymphatic vessels are formed from capillaries that create fine-meshed networks around the nodules and carry Lymph toward the regional Lymph Nodes for these organs.



Last update: 08/08/2026

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