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
Blood test identifies women at risk from Alzheimer's
Nov 06, 2009 |
5 / 5 (1) |
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Middle-aged women with high levels of a specific amino acid in their blood are twice as likely to suffer from Alzheimer's many years later, reveals a thesis from the Sahlgrenska Academy at the University of Gothenburg, Sweden. ...
1930s drug slows tumor growth
Medicine & Health / Medications
Nov 06, 2009 |
4.6 / 5 (8) |
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Drugs sometimes have beneficial side effects. A glaucoma treatment causes luscious eyelashes. A blood pressure drug also aids those with a rare genetic disease. The newest surprise discovered by researchers at the Johns ...
Magnetic nanoparticles to simultaneously diagnose, monitor and treat
Nanotechnology / Bio & Medicine
Nov 06, 2009 |
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(PhysOrg.com) -- Whether it's magnetic nanoparticles (mNPs) giving an army of 'therapeutically armed' white blood cells direction to invade a deadly tumour's territory, or the use of mNPs to target specific nerve channels ...
Small increases in phosphorus mean higher risk of heart disease
Nov 05, 2009 |
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Higher levels of phosphorus in the blood are linked to increased calcification of the coronary arteries— a key marker of heart disease risk, according to a study in an upcoming issue of Clinical Journal of the American So ...
'All-natural' sex pill contains Viagra chemical: FDA
Medicine & Health / Medications
Nov 05, 2009 |
3 / 5 (2) |
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The US food and drug safety watchdog warned Thursday that an over-the-counter men's sex aid, labeled as all-natural, contains a chemical similar to the active ingredient in Viagra and could be dangerous.
Researchers pioneer kidney disease prediction method
Nov 05, 2009 |
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(PhysOrg.com) -- A study into the relationship between antibodies and proteins in people with Lupus could mean earlier diagnosis of kidney disease in such patients, and lead the way for earlier diagnoses for ...
Nanoparticles may cause DNA damage across a cellular barrier
Nanotechnology / Bio & Medicine
Nov 05, 2009 |
4.3 / 5 (9) |
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(PhysOrg.com) -- Scientists have shown in the laboratory that metal nanoparticles damaged the DNA in cells on the other side of a cellular barrier. The research, by the University of Bristol, is published ...
Keeping hearts pumping with 'LifeFlow'
Nov 05, 2009 |
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When paramedics rush to the scene of a multi-car pileup or a terror attack, their first task is to assess who needs immediate care. But blood hemorrhaging can obscure damage, and the gruesome mess means paramedics can't always ...
Crossing the line: how aggressive cells invade the brain (w/ Video)
Nov 05, 2009 |
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In diseases such as multiple sclerosis, cells of the immune system infiltrate the brain tissue, where they cause immense damage. For many years, it was an enigma as to how these cells can escape from the bloodstream. ...
Study suggests dentists can identify patients at risk for fatal cardiovascular event
Nov 05, 2009 |
4 / 5 (1) |
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A new study indicates dentists can play a potentially life-saving role in health care by identifying patients at risk of fatal heart attacks and referring them to physicians for further evaluation.
First use of antibody and stem cell transplantation to successfully treat advanced leukemia
Nov 05, 2009 |
3 / 5 (1) |
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For the first time, researchers at Fred Hutchinson Cancer Research Center have reported the use of a radiolabeled antibody to deliver targeted doses of radiation, followed by a stem cell transplant, to successfully treat ...
Key player identified in cascade that leads to hypertension-related kidney damage
Nov 05, 2009 |
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A key player in a cascade that likely begins with stress and leads to high blood pressure and kidney damage has been identified by researchers who say the finding may lead to better ways to control both.
Heart disease effects perceived as more acute by people with PTSD
Medicine & Health / Psychology & Psychiatry
Nov 04, 2009 |
5 / 5 (1) |
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(PhysOrg.com) -- In a study of 1,022 men and women with heart disease, those with post-traumatic stress disorder perceived the effects of their disease as more burdensome and disabling than did those without PTSD, even when ...
Blood vessels might predict prostate cancer behavior
Nov 03, 2009 |
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A diagnosis of prostate cancer raises the question for patients and their physicians as to how the tumor will behave. Will it grow quickly and aggressively and require continuous treatment, or slowly, allowing therapy and ...
Statins may prevent blood clots in patients with cardiovascular disease
Nov 03, 2009 |
4 / 5 (1) |
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Statins may provide potentially life-saving benefits for patients with cardiovascular disease by helping reduce the incidence of blood clots. New research presented at the 75th annual international scientific assembly of ...
