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How do high altitudes affect respiration? That is the topic of this project. The course objective covered is number forty-five under respiratory system, which says, relate the exchange of gases during respiration to the chemistry and physics of gases. It is more difficult to breathe at high altitudes because of decreased atmospheric pressure. Pressure is an important factor in the mechanism of breathing (Betts, et. al., 2022, p. 962). Dalton’s law explains that each gas in a mixture exerts its own partial pressure and the partial pressure of each gas in a mixture equals the total pressure (Betts, et. al., 2022, pp. 970-971). How volume relates to pressure is explained by Boyle’s law (Betts, et. al., 2022, p. 962). This law describes how pressure and volume are inversely proportional, meaning that as volume increases pressure will decrease and as volume decreases pressure increases (Betts, et. al., 2022, p. 962). A mix of oxygen, nitrogen, carbon dioxide, and other gases make up the atmosphere (Betts, et. al., 2022, p. 970). Gases in an area of high pressure will move to areas of low pressure (Betts, et. al., 2022, p. 962). So if volume is decreased as pressure increases gasses will move to an area of lower pressure and if volume is increased as pressure decreases gases from areas of higher pressure will move to the area of lower pressure (Betts, et. al., 2022, p. 962). This is how gases enter and exit the lungs. To breathe we use our diaphragm and external intercostal muscles to change the volume of our lungs (Betts, et. al., 2022, p. 965). When these muscles are relaxed pressure within the alveoli of the lungs, referred to as intra-alveolar pressure, is equal to atmospheric pressure (Betts, et. al., 2022, p. 963). The alveoli are little sacs in the lungs that fill with air and is where gas exchange occurs (Betts, et. al., 2022, p. 956). When we inhale we contract the diaphragm and external intercostal muscles and increase the volume of our lungs causing the pressure to decrease (Betts, et. al., 2022, pp. 963-964). Because the pressure in the lungs is lower than atmospheric pressure, air from outside the body moves into the lungs (Betts, et. al., 2022, pp. 963-964). Atmospheric pressure is how much force is being exerted by gases on a surface (Betts, et. al., 2022, p. 962). This is why it becomes more difficult to breathe at higher altitudes. As altitude increases and atmospheric pressure decreases there are fewer gas molecules (Hock, 1970, p. 54). The percentage of oxygen is still 21% , it is the partial pressure of oxygen that decreases (Hock, 1970, p. 54). So there is less oxygen in each breath than at low altitudes (Barcroft, et. al., 1923, p.363). This can result in inadequate oxygen in the blood (Barcroft, et. al., 1923, p.362). If the amount of oxygen being absorbed is inadequate it can lead to hypobaric hypoxia or pulmonary edema (Sharma, 2023, para. 7 and 18). Hypoxia is when not enough oxygen is delivered to tissues for respiration, which can cause organ failure (Hock, 1970, pp. 53-54). Pulmonary edema is when fluid fills the alveoli (Sharma, 2023, para. 16-18). This causes less oxygen to be absorbed because oxygen diffuses across the wall of the alveoli, which is the respiratory membrane, and into capillaries where it binds to hemoglobin in red blood cells, but if there is fluid in the alveoli it means there is less surface area for the diffusion of oxygen (Hock, 1970, p. 54 and Betts, et. al., 2022, p. 957). This can also result in hypoxia (Sharma, 2023, para. 7 and 18). Pulmonary edema can occur at high altitudes because capillaries in the lungs dilate so more blood can flow to the lungs and absorb oxygen, but too high of altitudes cause the capillaries to dilate so much they leak and this fluid builds up in the lungs (Sharma, 2023, para. 16-18).
References
Barcroft, J., Binger, C. A., Bock, A. V., Doggart, J. H., Forbes, H. S., Harrop, G., Meakins, J. C.,
Redfield, A. C., Davies, H. W., Fetter, W. J., Murray, C. D., & Keith, A. (1923). Observations upon the Effect of High Altitude on the Physiological Processes of the Human Body, Carried out in the Peruvian Andes, Chiefly at Cerro de Pasco. Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character, 211, 351–480.
Betts, G. J., Johnson, E., Johnson, J. E., Korol, O., Kruse, D., Poe, B., Wise, J. A., Womble, M.,
& Young, K. A. (2022). Anatomy and Physiology 2e. Rice University. https://openstax.org/details/books/anatomy-and-physiology-2e
Hock, R. J. (1970). THE PHYSIOLOGY OF HIGH ALTITUDE. Scientific American, 222(2),
52–67
Sharma, P., Mohanty, S., & Ahmad, Y. (2023). A study of survival strategies for improving
acclimatization of lowlanders at high-altitude. Heliyon, 9(4). https://doi-org.uaf.idm.oclc.org/10.1016/j.heliyon.2023.e14929
Jazz’s STEAM project explains how higher altitudes affect our lungs. This is shown in her artwork with the lungs at lower and higher altitudes. Jazz uses Dalton’s and Boyle’s laws to explain pressure and volume and how that correlates with our lungs. Dalton’s law explains the partial pressure of gases, and Boyle’s law explains how pressure increases when volume decreases and vice versa. She further explains the correlation of these laws to the lungs, as within the lungs the pressure is lower than the atmosphere, so therefore the air outside moves into the lungs, which is seen in her artwork at the bottom of the mountain. When at high altitudes, there is less pressure, meaning there is less oxygen to breathe in, due to the partial pressure. This is seen in her artwork at the top of the mountain. With this, the effect on the lungs and body is explained. Hypobaric hypoxia is when not enough oxygen is getting to the rest of the body, and pulmonary edema is when the alveoli fill with fluid, leading to less oxygen being absorbed. At higher altitudes, someone is at more of a risk for pulmonary edema due to the body sending more blood to the lungs and then developing hypobaric hypoxia.