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
'Mini' transplant may reverse severe sickle cell disease
21 hours ago |
5 / 5 (2) |
0
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 |
4.2 / 5 (6) |
2
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 ...
Researchers demonstrate that stem cells can be engineered to kill HIV
Medicine & Health / HIV & AIDS
Dec 08, 2009 |
4.9 / 5 (14) |
0
(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.
New technology could boost disease detection tests' speed and sensitivity (w/ Video)
Nanotechnology / Bio & Medicine
Dec 07, 2009 |
5 / 5 (1) |
0
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 ...
Genetic studies reveal new causes of severe obesity in childhood
Dec 06, 2009 |
5 / 5 (2) |
1
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 ...
Researchers identify new stem cell
Dec 07, 2009 |
5 / 5 (4) |
0
(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 ...
Researchers finds hidden sensory system in the skin
Dec 08, 2009 |
5 / 5 (4) |
0
Researchers report that the human body has an entirely unique and separate sensory system aside from the nerves that give most of us the ability to touch and feel. Surprisingly, this sensory network is located throughout ...
Study highlights implications of influenza pandemics on blood supplies
Dec 09, 2009 |
not rated yet |
0
A German research team has examined data on supply and demand for blood transfusions against a computer simulation of an influenza pandemic, and discovered that a severe pandemic scenario could quickly lead to a deficit of ...
Young adults' blood lead levels linked to depression, panic disorder
Medicine & Health / Psychology & Psychiatry
Dec 07, 2009 |
3 / 5 (3) |
1
Young adults with higher blood lead levels appear more likely to have major depression and panic disorders, even if they have exposure to lead levels generally considered safe, according to a report in the December issue ...
Delivering medicine directly into a tumor
Dec 07, 2009 |
not rated yet |
0
Researchers at Burnham Institute for Medical Research at University of California, Santa Barbara have identified a peptide (a chain of amino acids) that specifically recognizes and penetrates cancerous tumors but not normal ...
Blood Enzyme Could Help Realize Clean Coal
Dec 03, 2009 |
4 / 5 (5) |
0
(PhysOrg.com) -- An enzyme in our blood that enables our lungs to exhale carbon dioxide could be the key to isolating carbon dioxide emissions from coal plants in order to store them safely underground. A ...
The blood detective
Dec 08, 2009 |
not rated yet |
0
(PhysOrg.com) --UCI hematologist Dr. Jae Chang employs medical sleuthing skills to identify rare blood disorders.
Drug shows promise for T315I-mutated chronic myeloid leukemia
Dec 07, 2009 |
not rated yet |
0
Results from a phase II clinical trial indicate a novel drug may provide a treatment option for chronic myeloid leukemia (CML) patients who do not respond to current therapies, researchers from The University of Texas M. ...
JAK2 inhibitor demonstrates effective, durable control of myelofibrosis
Dec 07, 2009 |
not rated yet |
0
A first-in-its class oral medication provides significant and durable relief for patients with a rare, debilitating and lethal bone marrow disorder called myelofibrosis, researchers at The University of Texas M. D. Anderson ...
Screening method able to identify newborns with blood disorder that affects immune system
Dec 08, 2009 |
not rated yet |
0
The testing of DNA from a statewide blood screening program for newborns in Wisconsin was able to identify infants with T-cell lymphopenia, a blood disorder that affects the child's immune system, a disease in which early ...
