topic 11: White blood cells: types, and their morphological properties and development. The mononuclear phagocytic system.

Question 1

what are WBCs and 2 main groups?

Answer 1

White blood cells, or leukocytes, are essential components of the immune system, playing a crucial role in defending the body against infections and foreign invaders. They can be broadly categorized into two groups based on the presence of granules in their cytoplasm: granulocytes and agranulocytes.

Question 2

granulocytes types

Answer 2

1.Neutrophils:
_Morphology: Multi-lobed nucleus (2-5 lobes), cytoplasm contains fine granules.
-Function: Phagocytosis and destruction of bacteria and fungi.
-Development: Myeloblast → Promyelocyte → Myelocyte → Metamyelocyte → Band cell → Mature neutrophil.

2.Eosinophils:
-Morphology: Bi-lobed nucleus, cytoplasm contains large, red-orange granules.
-Function: Combat parasitic infections, participate in allergic reactions.
-Development: Myeloblast → Promyelocyte → Myelocyte → Metamyelocyte → Mature eosinophil.

3.Basophils:
-Morphology: Bi-lobed or S-shaped nucleus, cytoplasm contains large, dark blue granules.
-Function: Release histamine and heparin during allergic reactions.
-Development: Myeloblast → Promyelocyte → Myelocyte → Metamyelocyte → Mature basophil.

Question 3

agranulocytes types

Answer 3

Lymphocytes:
-Morphology: Round or slightly indented nucleus, scant cytoplasm.
-Function: Adaptive immune response; B cells produce antibodies, T cells kill infected cells or help other immune cells.
-Development: Lymphoid stem cell → Lymphoblast → Prolymphocyte → Mature lymphocyte (B or T cell).

Monocytes:
-Morphology: Large cell, kidney-shaped or U-shaped nucleus, abundant cytoplasm.
-Function: Phagocytosis; differentiate into macrophages and dendritic cells in tissues.
-Development: Myeloid stem cell → Monoblast → Promonocyte → Mature monocyte

Question 4

development of WBCs

Answer 4

White blood cells develop from hematopoietic stem cells (HSCs) in the bone marrow through a process called hematopoiesis. This process involves multiple stages:

1.Hematopoietic Stem Cell (HSC):
Multipotent stem cell capable of giving rise to all blood cell types.

2.Common Myeloid Progenitor (CMP):
Differentiates into granulocytes, monocytes, erythrocytes, and megakaryocytes.

3.Common Lymphoid Progenitor (CLP):
Differentiates into lymphocytes (B cells, T cells, and natural killer cells).

Question 5

what is the Mononuclear phagocytic system?

Answer 5

The mononuclear phagocytic system (MPS), also known as the reticuloendothelial system (RES), consists of phagocytic cells primarily derived from monocytes. These cells play a key role in immune defense and tissue homeostasis.

Question 6

components of MPS

Answer 6

Components:

Monocytes: Circulate in the blood and migrate to tissues.

Macrophages: Differentiated monocytes that reside in tissues; they engulf and digest cellular debris, pathogens, and other particles.

Dendritic Cells: Specialized antigen-presenting cells that activate T lymphocytes.

Question 7

functions of MPS

Answer 7

Phagocytosis: Ingestion and destruction of microbes, apoptotic cells, and foreign substances.

Antigen Presentation: Process and present antigens to T cells, initiating the adaptive immune response.

Cytokine Production: Secretion of signaling molecules that modulate immune responses and inflammation.

Tissue Repair: Removal of dead cells and tissue remodeling.