Final answer:
The excessive amount of bleeding caused by Johnnie's arterial laceration when he was pushed into a plate-glass window is known as a hemorrhage. This type of severe bleeding requires prompt medical attention, especially if disorders like thrombocytopenia, which affect clotting, are present.
Step-by-step explanation:
When Johnnie was pushed into a plate-glass window and sustained a laceration of the forearm that cut into an artery, the arterial laceration caused an excessive amount of bleeding, which is called hemorrhage. Arterial bleeding is often more severe than venous bleeding due to the higher pressure in arteries, and as a result, the blood is expelled in spurts that are in time with the heartbeat, rather than the steady flow typically seen with venous bleeding. Injuries that lead to the severing of blood vessels can cause significant blood and blood component loss, which can quickly turn life-threatening if not managed properly. In the case of an arterial laceration, quick medical intervention is essential to control the bleeding and begin reparative treatments. Disorders like thrombocytopenia, where there is an insufficient number of platelets, can exacerbate the situation by hindering the blood's ability to clot, leading to even more excessive bleeding.