The bone marrow, i.e. the tissue found inside the bone cavities, is where most blood cells are created and developed. Blood is responsible for numerous critical functions as it circulates within the body. It ensures that tissues get adequate oxygen and critical nutrients such as sugars, fats, minerals and vitamins. It transports carbon dioxide to the lungs, where it is exhaled, while delivering waste products to the liver and kidneys for elimination. It carries chemical messengers i.e. hormones, to different body parts, enabling effective communication between within the body. The cells that are responsible for warding off infection and controlling bleeding are also part of the blood system.
Blood has three key cellular components: white blood cells, red blood cells and platelets. Each of these elements performs an important function. The red blood cells provide the body with oxygen; the white blood cells defend against infection, and the platelets are responsible for clotting of blood.
Disorders of the blood appear in different forms. They can manifest themselves as common reactions to irregular situations, such as a considerable rise in the number of white blood cells due to infection. They can also appear as abnormalities of the blood e.g. a shortage of cellular components caused by bone marrow failure. Additionally, abnormalities could either be related to quantity of cells or quality of cell function. It is beneficial for one to be aware of the meanings of the names of some of these blood disorders, as the name is usually indicative of the disorder itself.
Animals such as dogs, cats and horses also have multiple blood types, just as humans do. There are a number of animal blood banks that have been created, which rely on donated blood and offer type-matched blood to be used during surgeries and emergencies.