Ventilation-Perfusion Assignment Example | Topics and Well Written Essays - 500 words

Ventilation-Perfusion - Assignment Example Several factors affect resting metabolic rate and some include body mass, body composition, age, gender amongst others. For example, men usually demonstrate a higher absolute resting metabolic rate as compared to women (Connolly et al 196-201). When one is active, the body burns more calories than during rest. Various levels of physical activity such as walking, swimming decrease body weight by burning calories. Such activities also increase Basal Metabolic rates by building extra lean tissue (Connolly et al 196-201). On the other hand, maximum level of activity increases the metabolic rate and hence leads to proper maintenance of body weight. During rest, the alveolar change is minimal. However, during active or highly active period such as exercise and other conditions, alveolar pressure changes are high. Such a person is said to be on positive pressure ventilation. This may lead to a situation where alveolar pressure exceeds vascular pressure, and this may be detrimental to the flow of blood (Osborne 2). Usually, pulmonary pressure is high during exercise to avoid any hindrance that may occur to the blood flow (Osborne 3). Alveolar partial pressure of oxygen is a function of the ratio of ventilation to perfusion (Osborne 3). In a normal situation, the blood in the pulmonary capillaries equilibrates with alveolar oxygen pressure and carbon dioxide pressure (Osborne 4). The great ventilation and perfusion at the base of the lung allows greater gas exchange at the base of the lungs (Osborne 4). Therefore, such an arrangement allows adequate gas exchange, unless a disease occurs to disrupt it (Osborne 4). On the other hand , if regional hypoxia occurs that leads to reduced oxygenation of alveolus, local pulmonary vasoconstriction takes precedence (Osborne 4). The supply of blood to less oxygenated alveolus is reduced and directed to areas with an adequate supply of oxygen. These rates are able to maintain sufficient