Additional links of interest:

Overview of Shock:  Causes, Symptoms, and Treatment: 
http://www.emedicinehealth.com/shock/article_em.htm#shock_overview

Read about what happens in a blood bank:
http://www.medicinenet.com/script/main/art.asp?articlekey=13184

More cool stuff about skin grafts:
http://health.howstuffworks.com/skin-care/information/anatomy/skin-graft.htm