Ch 35 STRUCTURAL ORGANIZATION OF THE RESPIRATORY SYSTEM

movement of gases into and out of the lungs

movement of blood through the lungs

• between lung and blood
• across alveolar capillary membrane

• nasopharynx, oropharynx, larynx, tracheobrachial tree
• not in gas exchange

• psuedostratified cilliated ccolumnar epithelium
• mouth, nasal paassages, pharynx, tracheo, bronchi, bronchioles

• lobules - smallest unit of lung, 
• alveoli - site of gas exchange, increase surface area and decrease surface tension 
• alveolar macrophage - filter dust, pollen, infectious agent

bronchial circulation send blood to conductive airway and structure. bronchrial atery = oxygenated

keep lungs dry and prevent accumulation of fluids in plueral cavity

• parasympathetic  via vagus nerve, constrict bronchiole
• sympathetic vases relaxation, dilate bronchioles, blood vessel constriction, inhibit grandual secretion

• double layer membrane
• thin fluid seperate the two 
• plueral effusion - where serous fluid or implammatory exudate can accumulate

sweilling and inflammation of smooth tissue in lungs

movement of gases into and out of lungs through open aairway along pressure gradient

• intrapulmunary pressure - inside alveoli 
• plueral pressure - plueral cavity 
• intrathoracic pressure - thoracic cavity

• elastin and collagen fibers - elastic recoil
• surface tension - surfactant molecules by alveolar cells reduce tension

• airway resistance - impedement to flow of air as it moves to airway
• airway compression during forced expiration - e.g. copd

amount of air exchanged during normal and forced breathing

• Generalized hypoxia, which occurs at high altitudes and in people with chronic hypoxia due to lung disease, causes vasoconstriction throughout the lung.
• Prolonged hypoxia can lead to pulmonary hypertension and increased workload on the right heart, causing cor pulmonale.

• 4 factors:
• surface area
• thickness of alveolar capillar membrane
• difference in paartial pressure 
• diffusion characteristics of the gas

• blood
• hemoglobin carries oxygen
• co2 attaches to hemoglobin, dissolves in blood, and bicarbonate

• ventilation (atmoswphere and intraalveolar air)
• diffusion (exchagne between alveolar air and blood + tarnsport of gas)
• perfusion (exchange between blood and tissue + internal tissue respiration)

protects the lungs from the accumulation of secretions and from the entry of irritating and destructive substances; it is one of the primary defense mechanisms of the respiratory tract.

subjective sensation of difficulty in breathing that is seen in cardiac, pulmonary, and neuromuscular disorders that affect the respiratory muscles

• chemoreceptors
• lung receptors (stretch resceptors, irritant, j receptors)