Connective and supporting tissues

Blood cell production

Blood cell production (hematopoiesis) is a process of development for formed elements of blood. In the embryonic period, hematopoiesis means a process of blood tissue development. In the postembryonic period, hematopoiesis ensures physiological regeneration of formed elements.

Postembryonic hematopoiesis takes place in hematopoietic tissues: myeloid and lymphoid tissue

Myeloid tissue

• is hematopoietic tissue of the red bone marrow
• contains hematopoietic stem cells and connective tissue stem cells, as well as stem cells at different stages
• produces red blood cells, platelets, granulocytes, monocytes, lymphocyte precursors, and connective tissue precursor cells
• in adults, it is present in flat bones and in the epiphyses of tubular bones

Lymphoid tissue

• is found in the thymus, lymphatic nodes, spleen, and mucous membranes of internal organs
• provides for differentiation and maturing of T and B cells coming from the red bone marrow
• ensures an immune reaction development due to lymphocyte interaction and their interaction with antigen-presenting cells

The structure of myeloid and lymphoid tissues is studied by special histology

Mature formed elements and their precursor cells (which together constitute blood cell lineages) are derived from the same source: pluripotent hematopoietic stem cells

Diagram of hematopoiesis

Hematopoietic cells with distinct morphology

To study the morphology of hematopoietic cells (class IV-VI), bone marrow smears are used after azure II and eosin stain

Erythrocytopoiesis

Granulocytopoiesis

Lymphocytopoiesis and monocytopoiesis

Thrombocytopoiesis