The subpleural pulmonary microvasculature in newborn yak (Bos grunniens)

Abstract

Yak is a unique domestic animal of Qinghai-Tibetan Plateau. Its unique adaptability to the high altitude environment has been hypothesized due to special pulmonary microvasculature. However, the anatomical evidence is still less. The present study characterized the subpleural pulmonary microvascular architecture of newborn yak by vascular corrosion cast and the scanning electron microscopy. The results showed the dense vascular network occurred in subpleural area in newborn yak. Subpleural vascular network was found in most of observed areas, while the sparse vascular network crept onto the subpleural network in some fields of view. The subpleural microvessels and their branches made up of the subpleural microvascular network. According to the branching sequence of vessels, the subpleural arterioles could be divided into four grades: the arteriole, terminal arteriole, precapillary arteriole and capillary. The subpleural capillary network in the local area could be classified into three different forms, including sheetlike vascular network, wrinkled vascular network and weblike vascular network. It was the specific characteristics on the cast surface of the microvessels that was the adaptable peculiarities. Anastomoses were found between the pleural microvessels and the interlobular capillaries, or between the pleural microvessels and the subpleural capillaries, or between the interlobular capillaries and the subpleural capillaries. Therefore, there was significant difference on the subpleural pulmonary microvasculature between newborn yak and other adult mammals.

Morphological Analysis of the Lung of Neonatal Yak

“…However, a few studies have been conducted to elucidate the morphology of yak. In recent years, some investigators studied the anatomic structure of genital organs (Cui and Yu, 1999a), ovary (Cui and Yu, 1999b), pineal gland (Wang et al., 2007), cranial cervical ganglion (Shao et al., 2007), arterial supply of the eye (Shao et al., 2008) and subpleural pulmonary microvasculature (Du et al., 2009) of yak. However, there are no published reports on the lung of this species.…”

Segmentation features and structural organization of the intrapulmonary artery of the yak

“…Sasaki reported the complete intrapulmonary artery segmentation of rat for the first time (Sasaki et al, ). For the yak lung, previous studies focused on pulmonary microvasculature (Du et al, ), respiratory epithelium and gland, morphological analysis of neonatal yak lung (Yang et al, ), and distribution of vascular endothelial growth factor in plateau yak lung (He et al, ). This study is the first to report the divisions of intrapulmonary artery tree, intrapulmonary artery segmentation and structural organization in the yak.…”

“…Yaks are extensively found on the plateau of Western China in the alpine region and play an important part in the lives of humans. As a special plateau animal, many scholars have studied the yak in plateaus, focusing on reproductive organ anatomical features and ovarian morphology (Cui et al, 1999a,b; Yong et al, ), the pineal gland and thyroid structure (Wang et al, ), cranial neck ganglia and its branch (Shao et al, 2007, ), ventricular microvascular morphology (Cui et al, 2008; He et al, ), pulmonary microvasculature (Du et al, ), the sinus node and its artery (Duan et al, ), and placentome morphometric analysis (Liu et al, ). Studies on the plateau adaptive mechanism of the yak are available in the literature, including histochemical and ultrastructural observations of the respiratory epithelium and gland in Bos grunniens (Yang et al, ), morphological studies on the lung of yak (Yang et al, ), local anatomy of yak lung (Heath et al, ), structural characteristics and plateau adaptability of yak lung (Chen et al, ), and distribution of vascular endothelial growth factor in plateau yak lung (He et al, ).…”