Pulmonary System Quiz

Pulmonary System Structure and Function

• Vital capacity decreases and residual volume increases with age, reducing ventilatory reserves and leading to decreased ventilation-perfusion ratios.
• Immune dysregulation, "inflamm-aging," and increased infection risk occur with advancing age.
• Blood gas analysis shows that pH and PaCO2 levels do not change significantly with age, despite decreased sensitivity of chemoreceptors to gas partial pressures.
• Older adults have a diminished compensatory response to hypercapnia and hypoxemia, but their perception of dyspnea remains intact and may even be enhanced.
• Structural and mechanical changes in the lungs with age, such as loss of alveolar surface area, lead to a decline in PaO2 and ventilation-perfusion mismatch.
• The maximum PaO2 value in an older adult at sea level can be estimated by multiplying the person's age by 0.3 and subtracting the product from 100.
• Respiratory muscle strength and endurance decrease with age, leading to decreased exercise tolerance in older adults.
• The pulmonary system includes the two lungs, upper and lower airways, chest wall, diaphragm, and pulmonary and bronchial circulations.
• Gas exchange occurs in the respiratory bronchioles, alveolar ducts, and alveoli, with the alveoli serving as the chief gas-exchange units of the lungs.
• The pulmonary circulation is innervated by the autonomic nervous system, with vasodilation and vasoconstriction mainly controlled by local and humoral factors, such as arterial oxygenation and acid-base status.
• The chest wall, lined by the parietal pleura and encasing the lungs in the visceral pleura, consists of the skin, ribs, and intercostal muscles.
• Ventilation, controlled by the respiratory center in the brainstem and the ANS, involves the mechanics of breathing, including the diaphragm as the major muscle of inspiration and surfactant production by type II alveolar cells.

Pulmonary System Functions and Testing

• The chest wall is lined by the parietal pleura, while the lungs are encased in the visceral pleura, with the pleural space being the area where the two membranes come into contact.
• The pulmonary system enables oxygen to diffuse into the blood and CO2 to diffuse out, with ventilation being the process of air flowing into and out of the airways.
• Ventilation is mainly involuntary and controlled by the respiratory center in the brainstem and the ANS divisions, with lung receptors monitoring ventilation mechanics.
• Successful ventilation involves breathing mechanics, such as the diaphragm's role in inspiration and surfactant production by type II alveolar cells.
• Elastic recoil and compliance are key factors in lung function, with airway resistance being determined by various factors.
• Gas transport depends on ventilation, diffusion, perfusion, and efficient gas exchange relies on an even distribution of ventilation and perfusion within the lungs.
• Most oxygen diffuses into pulmonary capillary blood is transported by hemoglobin, and oxygen enters the body by diffusing down the concentration gradient from alveoli to capillaries.
• CO2 is more soluble in plasma than oxygen, and it diffuses readily from tissue cells into plasma.
• Spirometry, alveolar-arterial oxygen gradient, diffusing capacity, arterial blood gas analysis, and thoracic imaging are used to test pulmonary function.
• Aging affects the mechanical aspects of ventilation by decreasing chest wall compliance and elastic recoil of the lungs, reducing ventilatory reserve.
• Aging causes loss of alveolar wall tissue and enlargement, diminishing the gas diffusion surface area, and can result in a decrease in PaO2 levels but does not affect PaCO2 levels.
• Vital capacity decreases, and residual volume increases with age, while total lung capacity remains unchanged.