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Respiration
process of gas exchange between person and environment
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4 components of respiration
- 1. ventilation
- 2. alveolar-capillary gas exchange
- 3. transport of O2 and CO2 between tissues and lungs
- 4. movement of O2 and CO2 between systemic capillaries and tissues
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upper respiratory system
mouth, nose, pharynx, larynx
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lower respiratory system
- trachea
- lungs: bronchi, bronchioles, alveoli, pulmonary capillary network, pleural membranes
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intrapleural
pressure in the pleural cavity surrounding the lungs
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intrapulmonary
presssure within the lung
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tidal volume
500 mL of air inhailed and exhaled with each breath
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accessory muscles of respiration
- anterior nech muscles
- intercostal muscles
- abdominal muscles
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lun compliance
- stretchability of lung tissue
- decreases with ae
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atelectasis
collapse of a portion of a lung
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lung recoil
- continual tendency of the lung to collapse away from the chest wall
- necessary for normal exhalation
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surfactant
- lipoprotein
- reduces surfact tension in lung
- without it lung expansion is difficult
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diffusion
movement of gases from area of greater pressure to an area of lower pressure
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partial pressure
pressure exerted by each gas in mixure
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factors affecting O2 transport from lung to tissues
- cardiac output
- exercise
- # of erythrocytes and blood hematocrit
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transport of CO2 from cells to lung
- 65% carried in RBC's as bicarbonate
- 30% transported with hemoglobin as carbhemoglobin
- 5% transported in plasma as carbonic acid
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factors affecting respiratory function
- age
- environment
- lifestyle
- health status
- stress
- meds
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meds that affect respiration
- benzodiazepine sedative hypnotic
- antianxiety
- barbiturates
- narcotics (morphine, demerol)
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hypoventalation
- inadequate alveolar ventilation
- slow or shallow breathing
- leads to increase levels of CO2
- leads to decrease levels of O2
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hyperventalation
- more CO2 eliminated than is produced
- rate and depth of respirations decrease
- increased movement of air into and out of lungs
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Kussmaul's breathing
- hyperventalation with metabolic acidosis
- body attempts to compensate for increase metabolic acid by blowing off acid in CO2 form
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Cheyne strokes respirations
- very deep to very shallow with periods of apnea
- rhythmic waxing/waning of respirations
- caused by chronic diseases, increased intracranial pressure, drug overdose
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