Never heard that. I tend to disagree. You can look at anything anyway though.

No it falls under the category of the "Circulatory System."

No. Not According to the Transplant Act, blood is not an organ. It can be produced by body, where as an organ can not be. The bone marrow will be an organ, not blood. Hope this makes sense.

Not from what I learnt! Anything is possible though as all sciences have arguments about what things actually are :)

Blood IS an organ of the circulatory system.

Each system has it's own set of organs......

Yes, Organs included in the circulatory system are the heart, the blood vessels, and the blood. I know you think the blood can't be an organ but it is made up of cells just like all the other organs.

Organ; a grouping of tissues into a distant struture.... To me blood does not meet the strict defination. Having said that if one cares to think of blood as "performs a specialized task" than maybe. Many if not most also consider our skin the biggest organ, but I'll bet not everyone would agree. To paraphrase a quote I once saw - the problem is not in finding the correct word to use, the problem is agreeing on how we define the word. Good question +5

Blood has been determined to be an organ of the circulatory and immune systems in the scientific sense, as it is made up of specialized cells which perform critical functions of these systems. However, blood is not an organ in the legal sense. A transfusion cannot be considered an organ transplant in a court of law.

Yes blood is a part of the liquid, but water is the rest.

Maybe in the colloquial sense. An organ is basically a collection of specialised tissues, made up of specialised cells, that work together to carry out specific functions. Blood only partially fits that description in that you can't really consider blood to be tissue. Functionally blood could be considered informally to be a "liquid organ" in that it is a range of specialised cells that work together to carry out a specific range of functions. However, it wouldn't really fit into a strict physiological definition of an organ.

1) "Connective Tissue - There are many types of connective tissue in the body. Generally speaking, connective tissue adds support and structure to the body. Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. Some examples of connective tissue include the inner layers of skin, tendons, ligaments, cartilage, bone and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue." "Circulatory System: Major Role: The main role of the circulatory system is to transport nutrients, gases (such as oxygen and CO2), hormones and wastes through the body. Major Organs: Heart, blood vessels and blood." "Lymphatic/Immune System: Major Role: The main role of the immune system is to destroy and remove invading microbes and viruses from the body. The lymphatic system also removes fat and excess fluids from the blood. Major Organs: Lymph, lymph nodes and vessels, white blood cells, T- and B- cells." Source and further information: http://web.jjay.cuny.edu/~acarpi/NSC/14-anatomy.htm 2) "Questions like this do not, generally speaking, have a right or wrong answer. It is a matter of how the different parts of the body are defined. Statements like "blood is not an organ because it moves", or "blood is not an organ because we don't call it a transplant when we get someone else's blood" are meaningless. In the final analysis, an organ is something that is convenient to define as an organ for whatever purpose we have. Since we are medical scientists (for the purposes of this discussion), we define blood in a convenient way for us. If we were alchemists, we would define it as a humour, and lump it in with bile and so on. Crabcakes list of different levels of organization of bodliy parts is of great relevance here: tissues are groups of similar cells, organs are groups of tissues that function together (but often have multiple autonomous functions), and organ systems are groups of organs that function together. Blood is composed of many different components, including cells from widely different origins and of widely varying functions, as well as proteins, water, and inorganic molecules and ions. Certainly this is a substance much more complicated than what one would generally regard as a tissue. Blood's multiple functions make it also difficult to define as something MORE than an organ: an organ system. Generally speaking, an organ system is something that is defined as such because we perceive it to have an overall functional similarity between its parts. There are problems with this, of course. The nervous system and the endocrine system both have multiple functions, and in fact they overlap on almost all of their functions. Their structures are likewise similar, and most (if not all) neurotransmitters are also hormones (and vice versa). It might make sense to define these as one organ system: the neurendocrine system, as some have suggested. But current consensus is that they are more managable when considered as separate systems. Blood's functions overlap many organ systems. Blood has immune functions, for example (T cells, B cells, globulins, and so on). It has endocrine functions (in that it carries hormones from point A to point B). It has functions that are unique to it, as in the transport of oxygen, carbon dioxide, and other nutrients and waste products. It is probably best (as in most convenient) to consider blood an organ, rather than a tissue (it is too complicated) or an organ system (its functions are too diverse). This categorization is the most common one amongst medical scientists. Blood transfusions are, incidently, considered organ transplants, and the same considerations are necessary when transplanting blood as other organs. Skin is heavier than blood, and thus, regardless of what blood is, skin is the largest organ." Source and further information: http://answers.google.com/answers/threadview/id/564993.html