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10 Cards in this Set
- Front
- Back
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What is the function of surfactant?
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the surfactant layer produced by type II alveolar cells decreases surface tension at the air-epithelium level--alveolar surface tension thus preventin alveolar collapse during respiration
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What is the most important component of surfactant?
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DPPC is a phospholipid that is critical for air space stability. This agent is responsible for majority of surface tension-reducing properties of surfactant
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When does surfactant synthesis begin in development?
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it occurs in fetus after 35th week of gestation and is regulated by variety of hormones including cortisol, insulin, prolactin and thyoxine.
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What is respiratory distress syndrome (RDS) and relationship to surfactant?
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W,o enough surfactant in alveoli, they would collapse on each successive exhalation (known as atelectasis).This can occur in premfature infants whose lungs have not sufficiently developed to produce surfactant.
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What tx's help RDS?
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prophlactic administration of exogenous surfactant at birth to extremely premature infants and administration to symptomatic newborns reduces risk. Cortisol(a modulator of surfactant) given to mothers with threatened premature delivery decreases risk of RSD.
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What proteins are necessary for structure and function of surfactant?
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Surfactant proteins A (SP-A), B(SP-B), C (SP-C), D (SP-D)
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What is surfactant protein A?
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most abundant, responsible for surfactant homeostasis (regulating synthesis and secretion of surfactant by type II alveolar cell) also modulates immune response to viruses, bacteria, and fungi
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What is surfactant protein B?
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critical surface organizing protein responsible for adsorption and spreading on surface of alveolar epithelium. also needed for transformation of lamellar body into the thin surface film of surfactant
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What is surfactant protein C?
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only 1% of total mass of proteins-works with B in orientation of DPPC within the surfactant and maintenance of thin film layer in alveoloi.
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What is surfactant protein D?
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host defense. binds to microorganisms-gram negative bacteria and lymphocytes. Participates in inflammatory response in acute injury.
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