Related topics: cancer , stem cells
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
Scientists use nanosensors for first time to measure cancer biomarkers in blood
Nanotechnology / Bio & Medicine
Dec 13, 2009 |
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A team led by Yale University researchers has used nanosensors to measure cancer biomarkers in whole blood for the first time. Their findings, which appear December 13 in the advanced online publication of ...
Mechanism discovered by which body's cells encourage tuberculosis infection
Dec 10, 2009 |
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Scientists have discovered a signaling pathway that tuberculosis bacteria use to coerce disease-fighting cells to switch allegiance and work on their behalf. Epithelial cells line the airways and other surfaces ...
Researchers demonstrate that stem cells can be engineered to kill HIV
Medicine & Health / HIV & AIDS
Dec 08, 2009 |
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(PhysOrg.com) -- UCLA AIDS Institute researchers have for the first time demonstrated that human blood stem cells can be engineered to target and kill HIV-infected cells.
Chemical energy influences tiny vibrations of red blood cell membranes
Dec 21, 2009 |
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(PhysOrg.com) -- Much like a tightly wound drum, red blood cells are in perpetual vibration. Those vibrations help the cells maintain their characteristic flattened oval or disc shape, which is critical to ...
Bioengineered materials promote the growth of functional vasculature, new study shows
Dec 21, 2009 |
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Regenerative medicine therapies often require the growth of functional, stable blood vessels at the site of an injury. Using synthetic polymers called hydrogels, researchers at the Georgia Institute of Technology ...
Brain surgery evolves to destroy rogue blood vessels
Dec 16, 2009 |
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(PhysOrg.com) -- Over three decades, a world-recognized medical team at UC San Diego Medical Center has spurred the evolution of a complex surgery to destroy dangerous clusters of arteries and veins in the brain. Integrating ...
Study finds over 90 percent of people with gum disease are at risk for diabetes
Dec 14, 2009 |
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The study, led by Dr. Shiela Strauss, Associate Professor of Nursing and Co-Director of the Statistics and Data Management Core for NYU's Colleges of Dentistry and Nursing, examined data from 2,923 adult participants in the ...
Scientists crack mystery of protein's dual function
Dec 13, 2009 |
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Researchers at The Scripps Research Institute have solved a 10-year-old mystery of how a single protein from an ancient family of enzymes can have two completely distinct roles in the body. In addition to providing guidance ...
New inherited eye disease discovered
Dec 11, 2009 |
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University of Iowa researchers have found the existence of a new, rare inherited retinal disease. Now the search is on to find the genetic cause, which investigators hope will increase understanding of more ...
Killer catfish? Venomous species surprisingly common, study finds
Dec 10, 2009 |
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(PhysOrg.com) -- Name all the venomous animals you can think of and you probably come up with snakes, spiders, bees, wasps and perhaps poisonous frogs. But catfish?
'Mini' transplant may reverse severe sickle cell disease
Dec 09, 2009 |
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Results of a preliminary study by scientists at the National Institutes of Health and Johns Hopkins show that "mini" stem cell transplantation may safely reverse severe sickle cell disease in adults.
'Shoot-'em-up' video game increases teenagers' science knowledge
Dec 08, 2009 |
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While navigating the microscopic world of immune system proteins and cells to save a patient suffering from a raging bacterial infection, young teenage players of the "Immune Attack" video game measurably improved their understanding ...
New technology could boost disease detection tests' speed and sensitivity (w/ Video)
Nanotechnology / Bio & Medicine
Dec 07, 2009 |
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A team led by Yale University scientists has developed a way to rapidly manipulate and sort different cells in the blood using magnetizable liquids. The findings, which will be published the week of December ...
Researchers identify new stem cell
Dec 07, 2009 |
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(PhysOrg.com) -- Scientists have discovered a new type of stem cell in the skin that acts surprisingly like certain stem cells found in embryos: both can generate fat, bone, cartilage, and even nerve cells. These newly-described ...
Genetic studies reveal new causes of severe obesity in childhood
Dec 06, 2009 |
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Scientists in Cambridge have discovered that the loss of a key segment of DNA can lead to severe childhood obesity. This is the first study to show that this kind of genetic alteration can cause obesity. The results are published ...
