Oxygen Cascade and Disease

Paper Summary:

This paper explains that the main organ responsible for gas exchange, the lungs, are efficient not only in their anatomic and histological structure but also are physiologically efficient to provide oxygen to tissues and cells such that oxygen extraction can be increased in altered, demanding physiologic states within the bounds of physical laws. The author points out that the oxygen cascade, essentially described as the "diminishing returns" phenomenon, represents a natural barrier to the limits of mammalian and human cellular respiration. The paper concludes that, from uptake of oxygen, to transport of oxygen to the periphery to its delivery to tissues at the cellular level, at the different steps, oxygen tension decreases pathologies at the tissue level, which are heavily dependent on perfusion and are the most vulnerable to hypoxia.

Table of Contents:
Lung Anatomy and Physiology
Oxygen Cascade
Uptake in the Lungs
Carrying Capacity of Blood
Global Delivery from Lungs to Tissue
Regional Distribution of Oxygen Delivery
Diffusion from Capillary to Cell
Cellular Use of Oxygen
Lung Pathophysiology
Oxygen Cascade Pathophysiology and Relevant Disease States
Uptake in the Lungs
Carrying Capacity of Blood
Global Delivery from Lungs to Tissue
Conclusion

From the Paper:

"Delivery of oxygen to the tissues is heavily dependent on the heart and the vascular system associated with it. This branching, closed-circuit system perfuses all organ systems. In normal individuals, global delivery of oxygen (Do2) is often more than adequate to ensure that all tissues receive enough oxygen to meet their aerobic respiratory needs (Vo2). Do2 is the product of cardiac output (Qt) and oxygen content of blood (Cao2). Cao2 is similarly the product of oxygen saturation (Sao2), hemoglobin content (Hgb), and a constant K (the coefficient for hemoglobin-oxygen binding capacity)."

Sample of Sources Used:

• Hopley L & van Schalkwyk J. (1999). Lung function fundamentals. Retrieved May 13, 2007, from http://www.anaesthetist.com/icu/organs/lung/Findex.htm#lungfx.htm
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More papers on Oxygen Cascade and Disease:

• Term Paper # 133655 : "Disease and the Oxygen Cascade"
• Research Paper # 107754 : "Reactive Oxygen Species and Free Radicals in Aging"
• Descriptive Essay # 8022 : "Hemoglobin, Oxygen Transport and Nitric Oxide"

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