BIOB33H3 Lecture Notes - Intrapleural Pressure, Obstructive Lung Disease, Thoracic Cavity
20 Mar 2013
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External respiration: gas exchange between the blood and alveoli (air sacs) Gas transport: blood transports gases to tissues (cv system) Internal respiration: gas exchange between the blood and tissues (cv/tissues) Cellular respiration: use of o2 to produce atp (cells: functions. Nonrespiratory functions: route for water and heat loss, enhance venous return, acid-base balance (co2, vocalization, defense against inhaled invaders, sense of smell, alters blood composition, functional anatomy. Airways: smallest bronchioles have no cartilage; smooth muscle regulates air flow (bronchoconstriction and bronchodilation) Alveoli (air sacs: thin walled and surrounded by capillaries, large surface area for gas exchange, type i cells - simple squamous epithelium, type ii cells - secrete surfactant, macrophages fight invaders. Pleural sacs: each lung is separate, intrapleural fluid lubricates surfaces and helps lungs stick to thoracic wall, respiratory mechanics. Airway resistance: adjusted to meet the body"s needs, parasympathetic stimulation bronchoconstriction increased resistance decreased airflow, sympathetic stimulation/epinephrine bronchodilation decreased resistance increased airflow.
