Morphological Study of the Sinus Node and Its Artery in Yak

Abstract

The sinus node of yak has been studied by the histological methods and transmission electron microscopy. The sinus node artery of yak was also determined by the injection-corrosion casting technique, the angiography, and histological methods. The results showed that the sinus node of yak contained an extensive framework of collagen and two main type cells: pacemaker cells (P cells) and transitional cells (T cells). The P cells had a perinuclear clear zone, contained less myofibrils, and appeared smaller mitochondria than T cells. The T cells were longer and slender than P cells, and had a variety of shapes. At the periphery of sinus node there were many nerve fibers and ganglions. Gap junction did not reveal reaction with anti-connexin43, but it was detected by electron microscopy in the central part of sinus node of yak. The sinus node artery of yak originated from left coronary artery more frequently (98%) than by right (2%). The artery located at the periphery of sinus node. It had an internal elastic membrane throughout its course, and a large nerve bundle was found running in a longitudinal direction.

Changes in the Anatomic and Microscopic Structure and the Expression of HIF-1α and VEGF of the Yak Heart with Aging and Hypoxia

“…Therefore, as a researcher working with yaks, we argue that the best control was the newborn yak. Thirdly, the present research has proved that Tibetans, the Tibetan antelope and yak obtained genetic features of high-altitude hypoxia adaption at the physiological, morphological, and genetic levels [ 1 , 2 , 20 , 21 ].…”

“…Previously, it was found that the microvasculature and conduction system of the yak heart has unique characteristics [ 20 , 21 ], suggesting that the vasculature of the yak heart constructs an adaptive structure to cope with the low-oxygen situation. However, there is a little information on the levels of protein expression of HIF-1α and VEGF following the birth of yaks, and during their maturation at high altitude.…”

Fibrosis: a structural modulator of sinoatrial node physiology and dysfunction

“…Considerable physiological and structural evidence support the generalization that large mammals (including human, dog, pig, yak, horse, etc.) have a more compact and distinct SAN structure than smaller mammals (Keith and Flack, 1907 ; James, 1961 ; Opthof et al, 1987 ; Fedorov et al, 2009 , 2012 ; Duan et al, 2012 ; Lou et al, 2013 , 2014 ; Glukhov et al, 2015 ). Histological studies clearly demonstrated that interstitial fibrosis is an inherent component of normal SAN structure and can be traced from newborn hearts (Lev, 1954 ; Shiraishi et al, 1992 ; Alings et al, 1995 ).…”

Histology of Sinoatrial Node in the Dromedary Camel Foetus

“…Walls (1947) studied the development of the specialized conducting tissue of the human heart and found that the sinus node can be identified at 10 mm foetus. The sinus node of yak was studied using the histological methods (Duan et al, 2012).…”