Air that does not undergo respiratory exchange Inspiratory Reserve Volume

Air that does not undergo respiratory exchange

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– Air that does not undergo respiratory exchange Inspiratory Reserve Volume– additional air from deep breathExpiratory Reserve Volume– after exhale, additional air in lungs Residual Volume – volume of air that stays in the lungs following maximum exhalation Inspiratory Capacity– amount of air contained in lung at the end of maximal inhalationFunctional residual capacity– volume of air present in lungs at end of passive expirationVital Capacity– sum of inspiratory reserve and tidal volume Total lung capacity– total volume of lungs
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Control of Breathing:oRespiratory Center– receives and controls signals of neural, chemical, and hormonal nature and control the rate of depth of respiratory movements of the diaphragm and other respiratory muscles. 2 Main Area: Medullary Respiratory centerin the medulla oblongata. Is made up of 2 collections ofneurons called dorsal respiratory group (DRG)which controls normal quiet breathing & ventral respiratory group (VRG)which is used for forceful breathing and controls the rhythm of breathing. Pontine Respiratory group (PRG)in the pons may modify the rhythm of breathing during exercise, speaking, and sleep. The activity of the respiration center can be modified in response to inputs from various parts of the body in order to maintain homeostasis of breathing. These include: a.Cortical influences– allow conscious control of respiration that may be needed to avoid inhaling noxious gases or water. b.Chemoreceptors – central and peripheral chemoreceptors monitor levels of O2 and CO2 and provide input to the respiratory center. - Hypercapnia– A slight increase in PCO2 (and thus H+) / stimulates central chemoreceptors - Hypoxia– oxygen deficiency at tissue level / caused by low PO2 in arterial blood due to high altitude, airway obstruction of fluid in the lungs Exercise and the Respiratory System:oThe respiratory system and cardiovascular system make adjustments in response to both the intensity and durationof exercise As cardiac output rises, the blood flow to the lungs, termed pulmonary perfusion, increases as wellThe O2 diffusing capacity may increase threefold during maximal exercise so there is a greater surface area available for O2 diffusion Development of the Respiratory System:oThe respiratory system begins as an outgrowth of the endoderm called the Respiratory DiverticulumoSmooth muscle, cartilage, and connective tissue of the bronchial tubes and pleural sacs develop from the mesoderm Aging and the Respiratory System:oAging results in decreased:Vital capacity Blood O2 levelAlveolar macrophage activity Ciliary action of respiratory epithelia oElderly people are more susceptible to pneumonia, bronchitis, emphysema & other pulmonary disorders Transport of O2 and CO2 in the Blood: Oxygen: -1.5% of the O2 is dissolved in the plasma -98.5% of the O2 is carried by hemoglobin (Hb)Carbon Dioxide: -7% of the CO2 is dissolved in the plasma -23% of the CO2 is carried by Hb inside red blood cells as carbaminohemoglobin-70% of the CO2 is transported as bicarbonate ions (HCO3)Factors affecting the affinity of Hb for O2:-PO2-pH-Temperature-BPG-Type of Hb
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