Blood
hideBlood is a specialized bodily fluid that delivers necessary substances to the body's cells — such as nutrients and oxygen — and transports waste products away from those same cells.
In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma. Plasma, which comprises 55% of blood fluid, is mostly water (90% by volume), and contains dissolved proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), platelets and blood cells themselves. The blood cells present in blood are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates transportation of oxygen by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.
Vertebrate blood is bright-red when its hemoglobin is oxygenated. Some animals, such as crustaceans and mollusks, use hemocyanin to carry oxygen, instead of hemoglobin. Insects and some molluscs use a fluid called hemolymph instead of blood, the difference being that hemolymph is not contained in a closed circulatory system. In most insects, this "blood" does not contain oxygen-carrying molecules such as hemoglobin because their bodies are small enough for their tracheal system to suffice for supplying oxygen.
Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system.
Blood is circulated around the body through blood vessels by the pumping action of the heart. In animals having lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.
Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Ancient Greek word αἶμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.
For more information about Blood, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with blood
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Even the anticipation of sweets may cause our muscles to start taking up more blood sugar, say researchers reporting in the December issue of Cell Metabolism. That message is delivered via neurons in the brain's hypothalamus contai ...
Intelligent blood bags
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(PhysOrg.com) -- Have the blood supplies got too warm? Do they match the patient?s blood group? In the future, these kinds of questions will be answered by intelligent radio nodes attached to blood bags. These ...
Scientists discover genetic pattern that indicates early-stage lung cancer
7 hours ago |
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Wistar Institute researchers and collaborators from the University of Pennsylvania and New York University have identified immune system markers in the blood which indicate early-stage lung tumors in people at high risk for ...
Can heart disease treatments combat AMD?
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Can treatments that reduce risks for cardiovascular disease (CVD) also help combat age-related macular degeneration (AMD), an eye disease that affects millions of Americans? CVD and AMD share some risk factors-such as smoking, ...
MRI helps detect life-threatening pregnancy complication
13 hours ago |
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A study presented today at the annual meeting of the Radiological Society of North America (RSNA) revealed that MRI is a highly accurate means of identifying placenta accreta, a potentially life-threatening and increasingly ...
Britain's Royal Society puts rare scientific manuscripts online
Nov 30, 2009 |
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Historic manuscripts by Sir Isaac Newton, Benjamin Franklin and other ground-breaking scientists will be published online for the first time, Britain's Royal Society said Monday.
Study describes new tool in the fight against autoimmune diseases, blood cancers
Nov 30, 2009 |
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A study led by a Scripps Research Institute scientist describes a new, highly pragmatic approach to the identification of molecules that prevent a specific type of immune cells from attacking their host. The findings add ...
Stroke and heart disease trigger revealed in new research
Nov 30, 2009 |
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(PhysOrg.com) -- Scientists have identified the trigger that leads to the arteries becoming damaged in the disease atherosclerosis, which causes heart attacks and strokes, in research published today in the ...
Low-income women 4 times more likely to report fair or poor health
Nov 30, 2009 |
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Low-income women are four times more likely than higher-income women to report fair or poor health and nearly twice as likely to report a health condition that limits their basic physical activities, according to a new policy ...
High salt intake directly linked to stroke and cardiovascular disease
Nov 24, 2009 |
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High salt intake is associated with significantly greater risk of both stroke and cardiovascular disease, concludes a study published in the BMJ today.
New tools for prediction of disease progression in acute childhood leukemia
Nov 27, 2009 |
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(PhysOrg.com) -- Researchers at Uppsala University and University Children’s Hospital in Uppsala have devised powerful new tools for typing cells from children with acute lymphatic leukemia and for prediction of how children ...
New cancer target for non-Hodgkin's lymphoma
Nov 22, 2009 |
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Physician-scientists from Weill Cornell Medical College have discovered a molecular mechanism that may prove to be a powerful target for the treatment of non-Hodgkin's lymphoma, a type of cancer that affects lymphocytes, ...
Researchers identify role of gene in tumor development, growth and progression
Nov 20, 2009 |
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Virginia Commonwealth University Massey Cancer Center and VCU Institute of Molecular Medicine researchers have identified a gene that may play a pivotal role in two processes that are essential for tumor development, growth ...
Reduced skin infections in Northern Australian Aboriginal children
Nov 24, 2009 |
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A community-based program aimed at reducing the burden of skin disease across remote communities in Australia's Northern Territory has been successful according to a study published November 24 in the open-access journal ...
New tool for helping pediatric heart surgery
Nov 24, 2009 |
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A team of researchers at the University of California, San Diego and Stanford University has developed a way to simulate blood flow on the computer to optimize surgical designs. It is the basis of a new tool that may help ...
