Diapedesis refers to __________.

• A. the movement of white blood cells through the walls of blood vessels into surrounding tissues
• B. the fusion of vesicles with the plasma membrane to release their contents
• C. the process by which cells divide to form two daughter cells
• D. the uptake of extracellular fluid by a cell through endocytosis

Answer: (A)

Verified step by step guidance

1. Understand the term 'diapedesis' by breaking it down: it refers to a specific biological process involving white blood cells (leukocytes).
2. Recall that white blood cells play a key role in the immune response, often needing to move from the bloodstream to sites of infection or injury.
3. Recognize that diapedesis describes the movement of white blood cells through the walls of blood vessels (endothelial cells) into surrounding tissues, typically during an immune response.
4. Eliminate the other options by understanding their definitions: (1) 'fusion of vesicles with the plasma membrane' refers to exocytosis, (2) 'cells dividing to form two daughter cells' refers to mitosis, and (3) 'uptake of extracellular fluid by a cell' refers to pinocytosis.
5. Conclude that the correct answer is: 'the movement of white blood cells through the walls of blood vessels into surrounding tissues.'