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Hypoxia
Hypoxia means a lower than normal level of oxygen, and may refer to: Reduced or insufficient oxygen * Hypoxia (environmental), abnormally low oxygen content of the specific environment * Hypoxia (medical), abnormally low level of oxygen in the tissues ** Autoerotic hypoxia or erotic asphyxiation, intentional restriction of oxygen to the brain for sexual arousal ** Cerebral hypoxia, a reduced supply of oxygen to the brain ** Diffusion hypoxia or Fink effect, a factor that influences the partial pressure of oxygen within the pulmonary alveolus ** Histotoxic hypoxia, the inability of cells to take up or use oxygen from the bloodstream ** Hypoxemic hypoxia or hypoxemia, a deficiency of oxygen in arterial blood ** Hypoxic hypoxia, a result of insufficient oxygen available to the lungs ** Intrauterine hypoxia, when a fetus is deprived of an adequate supply of oxygen ** Generalized hypoxia is hypoxia distributed amongst all tissues ** Latent hypoxia is artificially raised oxygen concentrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (medical)
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either '' generalized'', affecting the whole body, or ''local'', affecting a region of the body. Although hypoxia is often a pathological condition, variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise.. Hypoxia differs from hypoxemia and anoxemia, in that hypoxia refers to a state in which oxygen present in a tissue or the whole body is insufficient, whereas hypoxemia and anoxemia refer specifically to states that have low or no oxygen in the blood. Hypoxia in which there is complete absence of oxygen supply is referred to as anoxia. Hypoxia can be due to external causes, when the breathing gas is hypoxic, or internal causes, such as reduced effectiveness of gas transfer in the lungs, reduced capacity of the blood to carry oxygen, compromised general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia In Fish
Fish are exposed to large oxygen fluctuations in their aquatic environment since the inherent properties of water can result in marked spatial and temporal differences in the concentration of oxygen (see oxygenation and underwater). Fish respond to hypoxia with varied behavioral, physiological, and cellular responses to maintain homeostasis and organism function in an oxygen-depleted environment. The biggest challenge fish face when exposed to low oxygen conditions is maintaining metabolic energy balance, as 95% of the oxygen consumed by fish is used for ATP production releasing the chemical energy of nutrients through the mitochondrial electron transport chain. Therefore, hypoxia survival requires a coordinated response to secure more oxygen from the depleted environment and counteract the metabolic consequences of decreased ATP production at the mitochondria. This article is a review of the effects of hypoxia on all aspects of fish, ranging from behavior down to genes. Hypoxia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (environmental)
Hypoxia refers to low oxygen conditions. Normally, 20.9% of the gas in the atmosphere is oxygen. The partial pressure of oxygen in the atmosphere is 20.9% of the total barometric pressure. In water, oxygen levels are much lower, approximately 7 ppm or 0.0007% in good quality water, and fluctuate locally depending on the presence of photosynthetic organisms and relative distance to the surface (if there is more oxygen in the air, it will diffuse across the partial pressure gradient). Atmospheric hypoxia Atmospheric hypoxia occurs naturally at high altitudes. Total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen, which is defined as hypobaric hypoxia. Oxygen remains at 20.9% of the total gas mixture, differing from hypoxic hypoxia, where the percentage of oxygen in the air (or blood) is decreased. This is common in the sealed burrows of some subterranean animals, such as blesmols. Atmospheric hypoxia is also the basis of altitude tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumor Hypoxia
Tumor hypoxia is the situation where tumor cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues. Hypoxic microenvironements in solid tumors are a result of available oxygen being consumed within 70 to 150 μm of tumour vasculature by rapidly proliferating tumor cells thus limiting the amount of oxygen available to diffuse further into the tumor tissue. In order to support continuous growth and proliferation in challenging hypoxic environments, cancer cells are found to alter their metabolism. Furthermore, hypoxia is known to change cell behavior and is associated with extracellular matrix remodeling and increased migratory and metastatic behavior. Changes in the glycolytic pathway A particular change in metabolism, historically known as the Warburg effect results in high rates of glycolysis in both normoxic and hypoxic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxic Hypoxia
Generalized hypoxia is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than normal oxygen content in the arterial blood, and consequently a reduced supply of oxygen to all tissues perfused by the arterial blood. This usage is in contradistinction to localized hypoxia, in which only an associated group of tissues, usually with a common blood supply, are affected, usually due to an insufficient or reduced blood supply to those tissues. Genralized hypoxia is also used as a synonym for hypoxic hypoxia This is not to be confused with hypoxemia, which refers to low levels of oxygen in the blood, although the two conditions often occur simultaneously, since a decrease in blood oxygen typically corresponds to a decrease in oxygen in the surroundi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generalized Hypoxia
Generalized hypoxia is a medical condition in which the tissues of the body are deprived of the necessary levels of oxygen due to an insufficient supply of oxygen, which may be due to the composition or pressure of the breathing gas, decreased lung ventilation, or respiratory disease, any of which may cause a lower than normal oxygen content in the arterial blood, and consequently a reduced supply of oxygen to all tissues perfused by the arterial blood. This usage is in contradistinction to localized hypoxia, in which only an associated group of tissues, usually with a common blood supply, are affected, usually due to an insufficient or reduced blood supply to those tissues. Genralized hypoxia is also used as a synonym for hypoxic hypoxia This is not to be confused with hypoxemia, which refers to low levels of oxygen in the blood, although the two conditions often occur simultaneously, since a decrease in blood oxygen typically corresponds to a decrease in oxygen in the surroundin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Hypoxia
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in order of increasing severity: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury. Cases of total oxygen deprivation are termed "anoxia", which can be hypoxic in origin (reduced oxygen availability) or ischemic in origin (oxygen deprivation due to a disruption in blood flow). Brain injury as a result of oxygen deprivation either due to hypoxic or anoxic mechanisms are generally termed hypoxic/anoxic injuries (HAI). Hypoxic ischemic encephalopathy (HIE) is a condition that occurs when the entire brain is deprived of an adequate oxygen supply, but the deprivation is not total. While HIE is as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (Kathryn Williams Album)
''Hypoxia'' is Kathryn Williams 12th album and was released by One Little Indian on 15 June 2015. The songs were initially conceived as a result of a 2013 writing commission from New Writing North in conjunction with the Durham Book Festival's 50th anniversary celebration of the publication of Sylvia Plath's 'The Bell Jar' novel. Kathryn performed five songs at the festival and completed writing the project whilst touring her ' Crown Electric' release. "So I was writing the songs in Travelodges and on the side of the A1 in between gigs. Those were some dark days with only the sound of the motorway and a Little Chef to drown my sorrows in," The ''Scottish Herald'' wrote the album was "a collection of rare eloquence and spectacular beauty" with ''Clash Magazine'' concluding "By inhabiting and responding to a genuinely significant work of literature, Williams has produced her own spellbinding work of art" Track listing From AllMusic. * Electric * Mirrors * Battleships * Cuck ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxemic Hypoxia
Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the body. Definition ''Hypoxemia'' refers to the low level of oxygen in blood, and the more general term ''hypoxia'' is an abnormally low oxygen content in any tissue or organ, or the body as a whole. Hypoxemia can cause hypoxia (hypoxemic hypoxia), but hypoxia can also occur via other mechanisms, such as anemia. Hypoxemia is usually defined in terms of reduced partial pressure of oxygen (mm Hg) in arterial blood, but also in terms of reduced content of oxygen (ml oxygen per dl blood) or percentage saturation of hemoglobin (the oxygen-binding protein within red blood cells) with oxygen, which is either found singly or in combination. While there is general agreement that an arterial blood gas measurement which shows that the partial pressure of o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoerotic Hypoxia
Erotic asphyxiation (variously called asphyxiophilia, hypoxyphilia or breath control play) is the intentional restriction of oxygen to the brain for the purposes of sexual arousal. The term autoerotic asphyxiation is used when the act is done by a person to themselves. Colloquially, a person engaging in the activity is sometimes called a ''gasper''. Erotic asphyxiation can lead to accidental death due to asphyxia. The erotic interest in asphyxiation is classified as a paraphilia in the ''Diagnostic and Statistical Manual'' of the American Psychiatric Association. Physiology Concerning hallucinogenic states brought about by chronic hypoxia, Dr. E. L. Lloyd notes that they may be similar to the hallucinations experienced by climbers at altitude. He further notes that no such state occurs in hypoxia brought about by sudden aircraft decompression at altitude. These findings suggest to him that they do not arrive purely from a lack of oxygen. Upon examining the studies on hypoxia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histotoxic Hypoxia
Histotoxic hypoxia (also called histoxic hypoxia) is the inability of cells to take up or use oxygen from the bloodstream, despite physiologically normal delivery of oxygen to such cells and tissues. Histotoxic hypoxia results from tissue poisoning, such as that caused by cyanide (which acts by inhibiting cytochrome oxidase) and certain other poisons like hydrogen sulfide (byproduct of sewage and used in leather tanning). Causes Histotoxic hypoxia refers to a reduction in ATP production by the mitochondria due to a defect in the cellular usage of oxygen. Cyanide An example of histotoxic hypoxia is cyanide poisoning. There is a profound drop in tissue oxygen consumption since the reaction of oxygen with cytochrome oxidase is blocked by the presence of cyanide. Cyanide binds to the ferric ion on cytochrome oxidase a3 and prevents the fourth and final reaction in the electron transport chain. This completely stops oxidative phosphorylation and prevents the mitochondria from p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudohypoxia
Pseudohypoxia refers to increased cytosolic ratio of free NAD to NADH in cells, caused by hyperglycemia. Diabetes Magazine: Hyperglycemic Pseudohypoxia and Diabetic Complications, March 12, 1993 Research has shown that declining levels of NAD+ during aging cause pseudohypoxia, and that raising nuclear NAD+ in old mice reverses pseudohypoxia and metabolic dysfunction, thus reversing the aging process. It is expected that human NAD trials will begin in 2014. Guardian Newspaper - Online, Dec 2013 Pseudohypoxia is a feature commonly noted in poorly-controlled . [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
