the factors the influence gas flow/ventilation and describe the disorders that arise when gas flow is impaired

What determines gas flow in the lungs?

airway resistance, lung compliance, alveolar surface tension

What is resistance in ventilation?

opposition to gas flow, depends on airway diameter, regulated by neural control

What is the equation for gas flow?

gas flow equals pressure divided by resistance

How does sympathetic stimulation affect airways?

causes bronchodilation, decreases resistance, increases gas flow

How does parasympathetic stimulation affect airways?

causes bronchoconstriction, increases resistance, decreases gas flow

What is lung compliance?

ability of lungs and thoracic cavity to stretch or expand, high compliance means easy expansion, low compliance means stiff lungs

What does lung compliance depend on?

lung elasticity, flexibility of thoracic muscles and joints, alveolar surface tension and surfactant production

What is alveolar surface tension?

attraction between water molecules in alveolar fluid, creates inward force that resists expansion

What is surfactant?

phospholipid protein complex produced by type II alveolar cells, reduces alveolar surface tension, prevents alveolar collapse

How does surfactant affect ventilation?

increases lung compliance, reduces effort needed to expand alveoli, facilitates ventilation

What are obstructive disorders?

disorders causing obstruction to airflow, reduced airway diameter increases resistance and decreases gas flow

What is an example of an obstructive disorder?

asthma causes airway inflammation and bronchoconstriction

What are restrictive disorders?

disorders restricting chest wall or lung expansion, reduce compliance, reduce ability to change lung volume

What is an example of a restrictive disorder?

muscular dystrophy weakens respiratory muscles and limits chest expansion

What causes Infant Respiratory Distress Syndrome?

lack of surfactant in premature infants, increased alveolar surface tension, increased risk of alveolar collapse

What are the consequences of surfactant deficiency in infants?

alveolar collapse, difficulty reinflating lungs, impaired ventilation

How is Infant Respiratory Distress Syndrome treated?

artificial surfactant administration