topic 11: WBC

Question 1

types & morphological properties: granulocytes with granules in cytoplasm

Answer 1

1.Neutrophils:
-neutral affinity
-Multi-lobed nucleus (2-5 lobes), cytoplasm contains fine granules.
-Phagocytosis of bacteria and fungi, first responders to infection.

2.Eosinophils:
-acidic affinity
-Bi-lobed nucleus, large granules that stain red with eosin.
-Combat parasitic infections, involved in allergic reactions.

3.Basophils:
-basic affinity
-Bi-lobed or S-shaped nucleus, large granules that stain blue with basic dyes.
-Release histamine and heparin, involved in inflammatory and allergic responses.

allDerived from myeloblasts in the bone marrow.

Question 2

agranulocytes

Answer 2

1.Lymphocytes:
Large, round nucleus that occupies most of the cell, scant(maigre) cytoplasm.

Types:
B cells: Produce antibodies.
T cells: involved in cell-mediated immunity (helper T cells, cytotoxic T cells).
Natural Killer (NK) cells: Attack virus-infected and tumor cells.

-Derived from lymphoid progenitor cells in the bone marrow, mature in lymphoid tissues (e.g., thymus for T cells).

2.Monocytes:
-Large cell with kidney-shaped or C-shaped nucleus, abundant cytoplasm.
-Differentiate into macrophages and dendritic cells in tissues; phagocytosis, antigen presentation.
- Derived from myeloid progenitor cells in the bone marrow.

Question 3

Development of White Blood Cells (Leukopoiesis)

Answer 3

Differentiation Pathways:
1.Myeloid Lineage: Produces granulocytes (neutrophils, eosinophils, basophils), monocytes, erythrocytes, and megakaryocytes (which form platelets).

lineage:
HS(stem)C → CommonMyeloidProgenitors → GranulocyteMonocyteProgenitor → Myeloblasts or Monoblasts.

Myeloblasts → Promyelocytes → Myelocytes → Metamyelocytes → Band Cells → Granulocytes (Neutrophils, Eosinophils, Basophils).

Monoblasts → Promonocytes → Monocytes → Macrophages/Dendritic Cells.

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2.Lymphoid Lineage: Produces lymphocytes (B cells, T cells, and natural killer cells).

HSC → CommonLymhoidProgenitor → Lymphoblasts.

Lymphoblasts (B Lineage) → Pro-B Cells → Pre-B Cells → Immature B Cells → B Cells.

Lymphoblasts (T Lineage) → Pro-T Cells → Pre-T Cells → Immature T Cells → T Cells.

Lymphoblasts (NK Lineage) → NK Cell Precursors → NK Cells.

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Question 4

The Mononuclear Phagocytic System (MPS)

Answer 4

Family of cells made of :

1.Monocytes: Circulate in the blood and migrate to tissues where they differentiate.
2.Macrophages: Derived from monocytes, found in tissues throughout the body (e.g., Kupffer cells in the liver, alveolar macrophages in the lungs, microglia in the brain).
3.Dendritic Cells: Derived from monocytes, important for antigen presentation and activation of T cells.

Functions:

a.Phagocytosis: Engulf and digest cellular debris, pathogens, and apoptotic cells.
b.Antigen Presentation: Process and present antigens to T cells to initiate adaptive immune responses.
c.Cytokine Production: Secrete cytokines that modulate immune responses and inflammation.