<prompt> Answer this question truthfullyWhat is the process by which platelets aggregate at the site of injury to form a temporary platelet plug following upregulation of GpIIbIIIa?  <response>: <reason> What is the process by which platelets aggregate at the site of injury to form a temporary platelet plug following upregulation of GpIIbIIIa? Platelets aggregate at the site of injury via crosslinking of GpIIbIIIa receptors with fibrinogen. 