The immune system

Pharyngeal (adenoid) tonsils

The pharyngeal (adenoid) tonsil (tonsilla pharyngeals, s.adenoidea) is unpaired, located in the area of the vault and partly the back wall of the pharynx, between the right and left pharyngeal pockets (Rosenmüller's fossae).

Palatine tonsil

The palatine tonsil (tonsilla palatum) is paired and located in the tonsillar fossa (fossa tonsillaris), which is a depression between the palatoglossal arch in front and the palatopharyngeal arch behind, which diverge downwards.

Lingual tonsil

The lingual tonsil (tonsilla lingualis) is unpaired and lies under the multilayered epithelium of the mucous membrane of the root of the tongue, often in the form of two clusters of lymphoid tissue.

The tonsils

Tonsils: lingual and pharyngeal (unpaired), palatine and tubal (paired) - located at the entrance to the pharynx from the oral cavity and from the nasal cavity, i.e. on the paths of food and inhaled air entering the body.

Thymus (thymus gland).

The thymus (or, as this organ was previously called, the thymus gland, goiter gland) is, like the bone marrow, the central organ of immunogenesis. Stem cells penetrating the thymus from the bone marrow with the blood flow, after passing a number of intermediate stages, turn into T-lymphocytes responsible for cellular immunity reactions.

Bone marrow

A distinction is made between red bone marrow (medulla ossium rubra), which in adults is located in the cells of the spongy substance of flat and short bones, the epiphyses of long (tubular) bones, and yellow bone marrow (medulla ossium flava), which fills the bone marrow cavities of the diaphyses of long bones.

Immune system organs

The organs of hematopoiesis and the immune system are closely related by common structure, origin and functions. Reticular tissue is the stroma of both the bone marrow (the organ of hematopoiesis) and the organs of the immune system.