SBA — Single Best Answer · Review
Question 363
Pathology → General
Classification
Question
SSBAQuestion Header
During an acute inflammatory response, circulating leucocytes leave the axial blood stream and subsequently cross the vascular wall. Which sequence most accurately describes the events leading to leucocyte emigration?
Question Stem
Select the single best answer.
Options
A
Rolling → stasis → emigration → margination → adhesion → pavementing
B
Stasis → margination → pavementing → rolling → adhesion → emigration
C
Margination → emigration → rolling → stasis → adhesion → pavementing
D
Stasis → adhesion → margination → emigration → rolling → pavementing
E
Pavementing → rolling → stasis → margination → emigration → adhesion
Explanation
As blood flow slows and stasis develops, leucocytes move towards the endothelial surface (margination), become arranged along it (pavementing), roll, adhere and finally emigrate through the vessel wall.
Option Validity
A) Rolling does not precede the slowing and marginal redistribution of leucocytes, and emigration is the terminal event.
C) Emigration cannot precede rolling and firm adhesion to the endothelium.
D) Margination precedes firm adhesion, and rolling occurs before emigration.
E) This reverses the early haemodynamic and cellular sequence and places adhesion after emigration.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 5: Pathology. General Pathology, pp.161–175.