A round cell having fine nuclear chromatin, prominent nucleoli and fine azurophilic granule. The cell is:
**Core Concept**
A round cell with fine nuclear chromatin, prominent nucleoli, and fine azurophilic granules is characteristic of a specific type of cell involved in the immune response. This cell type plays a crucial role in the body's defense against infections and foreign substances.
**Why the Correct Answer is Right**
The cell described is a type of lymphocyte, specifically a **plasma cell**. Plasma cells are mature B lymphocytes that have undergone a process called plasma cell differentiation, allowing them to produce large amounts of antibodies. The fine nuclear chromatin and prominent nucleoli are indicative of an active cell engaged in protein synthesis. The fine azurophilic granules are actually **secretory vesicles** containing antibodies, which are released from the cell to neutralize pathogens.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not match the description of the cell. The cell type described is not a **neutrophil**, which typically has a multilobed nucleus and coarse azurophilic granules.
**Option B:** This option is incorrect because it does not match the description of the cell. The cell type described is not a **eosinophil**, which typically has a bilobed nucleus and coarse eosinophilic granules.
**Option C:** This option is incorrect because it does not match the description of the cell. The cell type described is not a **basophil**, which typically has a large, darkly staining nucleus and coarse basophilic granules.
**Clinical Pearl / High-Yield Fact**
Plasma cells are responsible for producing the majority of antibodies in the body, making them a crucial component of the immune response. In conditions such as multiple myeloma, plasma cell proliferation can lead to an overproduction of antibodies, resulting in hyperviscosity syndrome.
**Correct Answer:** D.