Injured cells and nearby leukocytes emit chemical signals that draw more leukocytes in. What is this called?

1. Chemotaxis means movement in response to chemicals. 2. It is positive when the cell is attracted towards the stimulus rather than repelled from it. 3. Injured or infected cells and the leukocytes already present emit signals that draw more leukocytes to the site, so the movement runs up the chemical gradient. 4. Diapedesis names the crossing of the vessel wall, which happens before this attraction guides the cell through tissue. 5. Emigration is simply the other name for diapedesis, so it fails for the same reason. 6. Negative feedback describes a homeostatic loop that damps a change, whereas this signal amplifies the response, so it is the conceptual opposite. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 18 "The Cardiovascular System: Blood", section 18.4 Leukocytes and Platelets_