The pulmonary arteries of the yak.
A quantitative histological study was carried out on the pulmonary arteries of a female yak (Bos grunniens), a member of the genus Bos which comprises the various types of cattle. A characteristic feature of cattle is a muscular pulmonary vasculature which responds sensitively to alveolar hypoxia by constriction. The yak studied had thin-walled pulmonary arteries and showed no evidence of right ventricular hypertrophy. It is suggested that this may be a feature of adaptation (as contrasted to acclimatisation) to a life in the hypobaric hypoxia of high altitude.
D000222:Adaptation, Physiological; D000531:Altitude; D000818:Animals; D002417:Cattle / Q000033:anatomy & histology*; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology; D009131:Muscle, Smooth, Vascular / Q000033:anatomy & histology; D009929:Organ Size; D011651:Pulmonary Artery / Q000033:anatomy & histology*