Zones of the lung

From Wikipedia, the free encyclopedia

The zones of the lung proposed by West in 1964,^[1] divide the lung into three vertical regions, based upon the relationship between the pressure in the alveoli (PA), in the arteries (Pa), and the veins (Pv):

• #1: alveolar > arterial > venous
• #2: arterial > alveolar > venous
• #3: arterial > venous > alveolar

The ventilation/perfusion ratio is higher in zone #1 (the apex of lung when a person is standing) than it is in zone #3 (the base of lung.)

[edit] References

1. ^ West J, Dollery C, Naimark A. "Distribution of blood flow in isolated lung; relation to vascular and alveolar pressures". J Appl Physiol 19: 713–24. PMID 14195584. 

[edit] External links

• Physiology at MCG 4/4ch4/s4ch4_28
• Description at anaesthetist.com
• Animated diagram at sites.fasthosts.com

v • d • e Respiratory system, physiology: respiratory physiology Volumes lung volumes - vital capacity - functional residual capacity - respiratory minute volume - closing capacity - dead space - spirometry - body plethysmography - peak flow meter - thoracic independent volume - bronchial challenge test Airways ventilation (V) (positive pressure) - breath (inhalation, exhalation) -respiratory rate - respirometer - pulmonary surfactant - compliance - hysteresivity - airway resistance Blood pulmonary circulation - perfusion (Q) - hypoxic pulmonary vasoconstriction - pulmonary shunt Interactions ventilation/perfusion ratio (V/Q) and scan - zones of the lung - gas exchange - pulmonary gas pressures - alveolar gas equation - hemoglobin - oxygen-haemoglobin dissociation curve (2,3-DPG, Bohr effect, Haldane effect) - carbonic anhydrase (chloride shift) - oxyhemoglobin - respiratory quotient - arterial blood gas - diffusion capacity - Dlco Control of respiration pons (pneumotaxic center, apneustic center) - medulla (dorsal respiratory group, ventral respiratory group) - chemoreceptors (central, peripheral) - pulmonary stretch receptors (Hering-Breuer reflex) Insufficiency high altitude - oxygen toxicity - hypoxia