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Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
Hypoxia – This is defined as a shortage of oxygen supply to the cells of the body. It is encountered when there is insufficient oxygen in the inspired air or when the tissues are deprived of the normal amount of oxygen due to possibly poor circulation or a blood clot. In this case, tissue hypoxia results and if this occurs in the heart muscle it results in heart attacks or ischaemic heart disease. Hypoxia also depresses the brain as the brain is dependent on sufficient oxygen supplies for the proper functioning of nerve cells. When hypoxia of the brain occurs, a person becomes disorientated, loses all sense of danger, loses consciousness and coma sets in. Hypoxia may be due to decreased amount of oxygen in the air breathed in (inspired oxygen) as at high altitude, or may be due to lung disease when the oxygen cannot enter the red blood cells in the blood that flows through the lungs.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
David J. Baker, Naima Bradley, Alec Dobney, Virginia Murray, Jill R. Meara, John O’Hagan, Neil P. McColl, Caryn L. Cox
Hypoxia is defined as a shortage of oxygen supply to the cells of the body. This is encountered when there is insufficient oxygen in the inspired air or when the tissues are deprived of the normal amount of oxygen due to possibly poor circulation or a blood clot. In this case, tissue hypoxia results and if this occurs in the heart muscle it results in heart attacks or ischaemic heart disease. Hypoxia also depresses the brain as the brain is dependent on sufficient oxygen supplies for the proper functioning of nerve cells. When hypoxia of the brain occurs, a person becomes disoriented, loses all sense of danger, loses consciousness and coma sets in. Hypoxia may be due to decreased amount of oxygen in the air breathed in (inspired oxygen) as at high altitude, or may be due to lung disease when the oxygen cannot enter the red blood cells in the blood that flows through the lungs.
The Perfect Storm
Published in Joyce A. Hunter, Anger in the Air, 2016
Many of the effects caused by high altitude, drinking, smoking and toxic chemicals on our bodies seem to be due to a single problem—oxygen deprivation. To work properly, our brains need a certain amount of usable oxygen in our bloodstreams. Unfortunately altitude, alcohol, smoking, and toxic chemicals all reduce that usable oxygen level, which can leave passengers with a form of oxygen deprivation called “hypoxia.” The symptoms of hypoxia range from headaches, nausea, thirst, irritability, rage, sexual excitability, and loss of judgment and control to, at the extreme, seizures, paralysis, coma and death.
Oxygen: a new look at an old therapy
Published in Journal of the Royal Society of New Zealand, 2019
Richard Beasley, Diane Mackle, Paul Young
Hypoxaemia is defined as an abnormally low level of oxygen in the arterial blood, which is traditionally set at a PaO2 of <60 mmHg, or an arterial oxygen saturation (SaO2) of <90% (O’Driscoll et al. 2017). Hypoxaemia can be caused by a number of mechanisms, including reduced inspired oxygen tension (for example, at altitude), reduced ventilatory drive (for example, narcotic overdose), or impaired lung function (for example, pneumonia). In contrast, hypoxia is defined as a reduction of oxygen supply at the tissue level, which cannot be directly measured in clinical practice (O’Driscoll et al. 2017). In addition to hypoxaemia, other causes of hypoxia include anaemia, severe sepsis, poor cardiovascular function or cellular dysfunction. Hypoxia may lead to cell injury by reducing aerobic oxidative respiration, and if severe and prolonged may result in cell death. Clinically, lack of oxygen delivery to the tissues is the defining feature of ‘shock’, a condition which may rapidly lead to progressive multi-organ dysfunction, and risk of death.