This structure does vary across different universities, with some extending the course to six years with their students obtaining a BSc at the end of three years. Other universities also allow their students vary early exposure to both patients and the clinical aspects of medicine. Furthermore, different universities do adopt different teaching methods. This is discussed in more detail in the article entitled The Academic Side of Medicine. Readers should make themselves aware of this before choosing to apply to any institution.
You may ask how medicine differs from that of other science degrees. Unlike the other science degrees, medical students are not expected to go into vast amounts of detail. This is largely due to the vast volume of work that needs to be done. At times 5 years may even feel too short a time. However, this does not mean that a student can not dive into the complexities of a subject that they enjoy. As a medical student myself I can honestly tell you that the best approach to your degree is to take ownership of your own learning. If you find a topic fascinating then pursue it. Furthermore, you are even given the opportunity to intercalate into a BSc degree or even a Masters in a variety of subjects. For more details on this see the article on Intercalation.
In summary medicine is a demanding degree but one with many rewarding moments. It introduces you to a vast library of knowledge and then ultimately enables you to master an area of you choice. As a medical student myself and having spoken to so many I have come to the conclusion that although we may grumble at how hard we have to work and how difficult our working lives will be, very few of us regret our decision. Most of us are driven by those moments where we feel that we have made a positive difference; even if it's only a passing smile from a patient on the hospital corridor.