Name the formed elements that arise from myeloid stem cells. Name those arising from lymphoid stem cells.
The correct answer and explanation is :
Formed Elements Arising from Myeloid and Lymphoid Stem Cells
The formed elements of blood arise from hematopoietic stem cells (HSCs) in the bone marrow. These stem cells differentiate into two major lineages: myeloid stem cells and lymphoid stem cells.
- Formed elements arising from Myeloid Stem Cells:
- Erythrocytes (Red Blood Cells – RBCs)
- Platelets (Thrombocytes)
- Leukocytes (White Blood Cells – WBCs):
- Neutrophils
- Eosinophils
- Basophils
- Monocytes (which further differentiate into macrophages and dendritic cells)
- Formed elements arising from Lymphoid Stem Cells:
- Lymphocytes (White Blood Cells – WBCs):
- B lymphocytes (B cells)
- T lymphocytes (T cells)
- Natural Killer (NK) cells
Explanation
Blood cell formation, known as hematopoiesis, occurs in the bone marrow. It starts with multipotent hematopoietic stem cells (HSCs) that give rise to two progenitor lines: myeloid stem cells and lymphoid stem cells.
Myeloid stem cells produce most of the body’s formed elements, including erythrocytes, which carry oxygen; platelets, which aid in clotting; and several types of leukocytes, such as neutrophils, eosinophils, basophils, and monocytes, which are essential for innate immunity and inflammatory responses.
Lymphoid stem cells exclusively give rise to lymphocytes, which play a critical role in adaptive immunity. B cells produce antibodies, T cells help regulate immune responses and attack infected cells, and natural killer (NK) cells provide rapid responses to virus-infected and cancerous cells.
This differentiation is regulated by cytokines and growth factors, ensuring a proper immune response and homeostasis.