Blood is a liquid that is pumped by the heart through the blood vessels to deliver nutrients and oxygen to the cells in the human body.Bartleby Bookstore: Anatomy of the Human Body: The Blood American Red Cross: About Blood

Blood full of oxygen flows from the heart bright red. When returning to the heart, blood has less oxygen and appears bluish when compared to fully oxygenated bloodAmerican Red Cross: About Blood

There are four main principle blood types -- A, B, AB and O. The type is determined by the specifc combination of antibodies and antigens a person's blood contains.Dennis O'Neil: ABO Blood Types Blood can further be characterized as negative or positive, depending on whether it contains the Rh antigen. Blood types need to be checked for compatibility before a transfusion to avoid potentially fatal complications.Nobleprize.org: Blood Groups, Blood Typing and Blood Transfusions

1. Red blood cells: Carry oxygen from the lungs to all the body tissues
2. White blood cells: Defend against infection
3. Platelets: Involved in clotting process of blood
4. Plasma: Liquid component of blood, replenishes or absorbs excess water from tissue, maintains blood pressure, helps regulate body temperature.Merck Manuals: Components of Blood

Some factors that can impact the health of blood are diseases, the amount of iron and vitamins in the diet and exposure to radiation or chemicals.Student BMJ: Iron: Keeping Blood Healthy Mayo Clinic: Anemia: Prevention Mayo Clinic: Thalassemia: Lifestyle and Home Remedies Cancer Answers: Acute Leukemia Treatment Information

Health problems that involve the blood are: anemia, leukemia, Hodgkin's disease, Von Willebrand disease and hemophilia.Merck Manuals: Blood Disorders

Vlad Tepes ( Dracula ) story. He was the second son of a Transylvanian nobleman. He was named prince of Transylvania and voivode (prince) of Wallachia and became ruler while still a child. Over the next several years, he struggled against the Ottoman Turks, losing and regaining his throne. Through an arranged marriage to a Hungarian noblewoman, he sired his daughter, Lilith. He sent his wife away and later married a woman named Maria, with whom he had a son named Vlad Tepes. He had a son with his third wife Domini named Janus. Vampires are mythical creatures that drink blood directly for sustenance, usually with a preference for human blood. Cultures all over the world have myths of this kind; for example the 'Nosferatu' legend, a human who achieves damnation and immortality by drinking the blood of others, originates from Eastern European folklore.