The word shock is used differently by the medical community and the general public. The connotation by the public is an intense emotional reaction to a stressful situation or bad news. The medical definition of shock is much different. Medically, shock is defined as a condition where the tissues in the body don't receive enough oxygen and nutrients to allow the cells to function. This ultimately leads to cellular death, progressing to organ failure, and finally, if untreated, whole body failure and death. How the body works Cells need two things to function: oxygen and glucose. This allows the cells to generate energy and do their specific jobs. Oxygen in the air enters the body through the lungs; where oxygen molecules cross into the smallest blood vessels, the capillaries, and are picked up by red blood cells and attached to hemoglobinmolecules. The red blood cells are pushed through the body by the actions of the pumping heart and deliver the oxygen to cells in all the tissues of the body. The hemoglobin then picks up carbon dioxide, the waste product of metabolism, where it is then taken back to the lungs and breathed out into the air, whereby the whole cycle begins again. Glucose is generated in the body from the foods we eat. Glucose travels in the blood stream and uses an insulin molecule to "open the door," where it then enters the cell to provide energy for cellular metabolism.