Agranulocytes Flashcards

Agranulocytes Overview

• Agranulocytes are leukocytes that lack visible cytoplasmic granules and possess a spherical or kidney-shaped nucleus.
• They are divided into two primary types: Lymphocytes and Monocytes.

Lymphocytes

• Lymphocytes are a type of agranulocyte known as "killer cells" and are crucial for immunity and immune memory.
• They are the second most numerous type of white blood cells in circulation.
• The nucleus is spherical, creating a rim-like appearance of the cytoplasm, which is light blue and stains purple.
• Primarily located in lymphoid tissues such as lymph nodes and the spleen, with a small number circulating in the blood.
• Two main types of lymphocytes: T-lymphocytes (T cells) and B-lymphocytes (B cells).

Immune Memory

• Immune memory refers to the immune system's ability to remember past exposures to pathogens, enabling quicker protection upon re-exposure.

T-Lymphocytes

• T-lymphocytes target virus-infected cells and tumor cells, acting as conductors in the immune response.

B-Lymphocytes

• B-lymphocytes transform into plasma cells, producing antibodies that specifically target antigens.

Antibodies

• Antibodies are proteins that initiate an immune response against specific antigens.

Monocytes

• Monocytes are the largest type of leukocytes and stain dark purple, with light purple cytoplasm.
• The nucleus of monocytes has a kidney shape, reminiscent of an irregular "M."
• Upon leaving the bloodstream through diapedesis, monocytes differentiate into macrophages.
• They play a crucial role in phagocytizing viruses, intracellular bacterial parasites, and chronic infections, effectively activating lymphocytes to respond.

Macrophages

• Macrophages are a type of leukocyte derived from monocytes that activate lymphocytes and phagocytize harmful entities.
• They move and extend their reach using pseudopods, often referred to as "false feet."

Summary of Key Characteristics

• Lymphocytes are characterized by their light blue cytoplasm and purple-staining nucleus, playing essential roles in immune memory and response.
• Monocytes, possessing a distinct kidney-shaped nucleus, are critical for phagocytizing harmful agents and facilitate lymphocyte activation.
• Macrophages, which evolve from monocytes, serve the purpose of combating pathogens and are pivotal in immune system signaling.

Test your knowledge on agranulocytes with this quiz. Explore definitions, types, and characteristics of these important leukocytes. Perfect for biology students looking to reinforce their understanding of the immune system.