What does the cell at the arrow secrete?

What does the cell at the arrow secrete?

• A. Histamine
• B. Mucus
• C. Elastic Fibers
• D. Antibody

Answer: (D)

This question is about identifying a cell type specialized for producing a specific protein and understanding what that protein does. The cell shown is a plasma cell, which arises from a B lymphocyte and is dedicated to making antibodies (immunoglobulins). Its appearance—lots of rough endoplasmic reticulum giving a deeply basophilic cytoplasm, a prominent Golgi area, and an eccentrically placed nucleus with a clock-face chromatin pattern—signals heavy protein synthesis and secretion. Antibodies are secreted into the extracellular space and blood to recognize and bind specific antigens on pathogens. This binding can neutralize pathogens directly, mark them for attack by other immune cells (opsonization), or activate the complement system to help clear infections. Histamine would come from mast cells or basophils, involved in allergic and inflammatory responses. Mucus is produced by goblet cells. Elastic fibers are structural components produced by fibroblasts and other cells. The features and function point to antibodies as the secreted product.

This question is about identifying a cell type specialized for producing a specific protein and understanding what that protein does. The cell shown is a plasma cell, which arises from a B lymphocyte and is dedicated to making antibodies (immunoglobulins). Its appearance—lots of rough endoplasmic reticulum giving a deeply basophilic cytoplasm, a prominent Golgi area, and an eccentrically placed nucleus with a clock-face chromatin pattern—signals heavy protein synthesis and secretion.

Antibodies are secreted into the extracellular space and blood to recognize and bind specific antigens on pathogens. This binding can neutralize pathogens directly, mark them for attack by other immune cells (opsonization), or activate the complement system to help clear infections.

Histamine would come from mast cells or basophils, involved in allergic and inflammatory responses. Mucus is produced by goblet cells. Elastic fibers are structural components produced by fibroblasts and other cells. The features and function point to antibodies as the secreted product.