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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
Study shows a key protein helps control blood pressure
Dec 23, 2009 |
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University of Iowa researchers have shown that a protein channel helps nerve sensors in blood vessels keep blood pressure in check. Without the protein channel, known as ASIC2, the sensors are unable to send the brain the ...
Broken genomes behind breast cancers
Dec 23, 2009 |
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The first detailed search of breast cancer genomes to uncover genomic rearrangements is published today. The team characterised the ways in which the human genome is broken and put back together in 24 cases of breast cancer.
First adhere, then detach and glide forward
Dec 23, 2009 |
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How do one-celled parasites move from the salivary gland of a mosquito through a person's skin into red blood cells? What molecular mechanisms form the basis for this very important movement of the protozoa? ...
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 ...
High-blood-pressure treatment for the over-80s too aggressive, warns expert
Dec 23, 2009 |
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People over 80 years are being treated too aggressively for high blood pressure, warns an expert in an editorial in BMJ Clinical Evidence this week.
The number of 85-year-olds will increase by a third by 2020
Dec 23, 2009 |
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Health and social care provision needs to be put in place for a large increase (33%) in the 85 year old population in the UK by 2020, according to a study published today in the British Medical Journal.
Team makes breakthrough demonstration of pH-regulating protein
Dec 22, 2009 |
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Researchers have identified the protein mechanism that senses bicarbonate fluctuations and adjusts blood pH levels.
New tool for early diabetes detection in adults
Dec 21, 2009 |
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(PhysOrg.com) -- A simple questionnaire developed by researchers at Weill Cornell Medical College can promote early detection of diabetes in adults so they can dramatically reduce their risk.
Anti-inflammatory drugs interfere with aspirin's clotting ability
Dec 23, 2009 |
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A new study conducted at Ben-Gurion University of the Negev (BGU) reveals that Celebrex and other anti-inflammatory coxib medications may counter the positive effects of aspirin in preventing blood clots.
Bacteria make the artificial blood vessels of the future
Dec 22, 2009 |
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The cellulose produced by bacteria could be used for artificial blood vessels in the future as it carries a lower risk of blood clots than the synthetic materials currently used for bypass operations, reveals ...
CT: The first-line imaging choice of physicians for the diagnosis of pulmonary embolism
Dec 22, 2009 |
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Computed tomography (CT), a highly accurate, readily available medical imaging technique, is the overwhelmingly preferred technique of emergency physicians and radiologists for the diagnosis of pulmonary embolism (PE), according ...
Good cholesterol not as protective in people with type 2 diabetes
Dec 21, 2009 |
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High-density lipoprotein (HDL), known as "good" cholesterol, isn’t as protective for people with type 2 diabetes, according to research reported in Circulation: Journal of the American Heart Association.
Drug for Multiple Myeloma Demonstrated to Significantly Extend Disease-Free Survival
Dec 21, 2009 |
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(PhysOrg.com) -- Initial results from a large, randomized clinical trial for patients with multiple myeloma, a cancer of the blood and bone marrow, showed that patients who received the oral drug lenalidomide (Revlimid, also ...
Self-monitoring with blood glucose test strips inefficient use of health-care resources
Dec 21, 2009 |
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Routine self-monitoring of blood glucose levels by people with type 2 diabetes who are not taking insulin is an ineffective use of health resources as the modest benefits are outweighed by the significant cost of test strips, ...
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