Differential Blood Count and Formed Elements of Blood

These flashcards cover key terms and definitions related to the formed elements of blood and differential blood count from the lecture notes.

Erythrocytes

Physical Description

• Small, biconcave disc shape
• Anucleated (lacks a nucleus)
• Reddish color due to hemoglobin

Function

• Responsible for transporting oxygen and carbon dioxide in the blood

Leukocytes

Physical Description

• Larger than erythrocytes
• Nucleated
• Generally colorless without staining
• Distinct types have varying appearances

Function

• Part of the immune system
• Protecting the body against infection

Thrombocytes

Physical Description

• Very small
• Irregular-shaped cell fragments
• Anucleated
• Appear granular due to internal components

Function

• Essential for blood clotting

Neutrophils

Physical Description

• Most abundant WBC
• Nucleus is multi-lobed (typically 3-7 lobes), often appearing as several distinct clumps connected by thin strands
• Cytoplasm contains fine, pale (neutral-staining) granules that are difficult to distinguish

Function

• Perform phagocytosis, especially against bacteria

Basophils

Physical Description

• Rarest WBC (0.5-1%)
• Nucleus is often large, U- or S-shaped, and usually obscured by very large, coarse, dark purple-blue cytoplasmic granules

Function

• Mediate allergic reactions and inflammation by releasing histamine and other mediators

Eosinophils

Physical Description

• Nucleus is typically bi-lobed (like a figure-8 or dumbbell shape)
• Cytoplasm is packed with large, prominent red-orange (acid-staining) granules
• Accounts for 2-4% of leukocytes

Function

• Involved in the destruction of parasitic worms
• Modulate allergic reactions

Monocytes

Physical Description

• Largest WBC
• Nucleus is large, kidney-shaped or U-shaped, often indented (reniform)
• Cytoplasm is abundant and pale blue, without visible granules (agranulocyte)

Function

• Can transform into macrophages and perform phagocytosis of pathogens and cellular debris

Lymphocytes

Physical Description

• Nucleus is large, spherical or slightly indented, and stains darkly, often filling most of the cell
• Cytoplasm is a thin, scant rim of pale blue surrounding the nucleus (agranulocyte)

Function

• Key components of adaptive immunity, including B cells (antibody production) and T cells (cell-mediated immunity)