Definition

1. Noun:
   • A cellular process of ingestion: Pinocytosis is a specific biological mechanism where a living cell actively takes in ("engulfs") tiny droplets of fluid from its external environment. The cell membrane folds inward to form a small vesicle that encloses the fluid, which is then brought into the cell's interior for incorporation and use.

Usage

• Pinocytosis is a fundamental process for cellular nutrition and signaling. It is a form of endocytosis, specifically for liquids, distinct from phagocytosis, which is for solid particles.
• This term is used almost exclusively in scientific contexts, particularly in cell biology, physiology, and medicine.

Examples

• Noun:
  • Nutrient absorption in the small intestine involves pinocytosis by the epithelial cells lining the gut.
  • The researcher studied how certain hormones stimulate pinocytosis in target cells.

Advanced Usage

• "Constitutive pinocytosis": Refers to the continuous, non-selective form of fluid uptake that occurs in many cell types as a baseline activity.
  • Macrophages exhibit high rates of constitutive pinocytosis.
• "Receptor-mediated pinocytosis": A selective form where specific molecules in the fluid bind to receptors on the cell membrane, triggering the engulfing process more efficiently.
  • Cholesterol enters cells via receptor-mediated pinocytosis.

Variants and Related Words

• Pinocytotic (adj): Relating to or characterized by pinocytosis.
  • The pinocytotic vesicles were visible under the electron microscope.
• Pinocytose (v): (Less common) To engage in or undergo pinocytosis.
  • Certain white blood cells can pinocytose surrounding fluid.

Synonyms

• Fluid-phase endocytosis: A more descriptive technical synonym.
• Cell drinking: An informal, illustrative term comparing the process to a cell "drinking" its environment.

Related Concepts (Not Phrasal Verbs or Idioms)

• Endocytosis: The broader category of cellular uptake processes that includes pinocytosis.
• Phagocytosis: ("Cell eating") The engulfment of solid particles.
• Exocytosis: The reverse process, where a cell expels material.

Noun

1. process by which certain cells can engulf and incorporate droplets of fluid