A microscopic study of the external carotid artery transitional zone of the adult male dog

Abstract

Structure and length of transitional zone in the dog's external carotid artery was documented. Six normal adult male dogs were studied. The specimens were processed in the routine way by light and electron microscopy. It was established that the transitional zone with 17-mm length contains parallel and fenestrated elastic fibres. In the transitional zone, the elastic fibres in the extracellular space were greater in number than collagen fibres. However, in the non-transitional zone, the rows of smooth muscle cells were greater in number. There were more collagen fibres than elastic fibres in the extracellular space and the elastic fibres appeared to be fragmented. Therefore, the transitional zone showed a structure intermediate between those of elastic and muscular arteries. The involvement of a special structure of transitional zone in vascular disease such as atherosclerosis is suggested.

Optimized design of an arterial network model reproduces characteristic central and peripheral haemodynamic waveform features of young adults

“…In addition to elastic arteries being closer to the heart and muscular arteries being further away, there are known transition points along a given arterial pathway where there is a substantial increase in wave speed and distinct change in morphological features from one artery to the next; this indicates a transition from predominantly elastic to more muscular arteries. These points are at the distal ends of the axillary artery for the upper limbs (Bjarnegård & Länne, 2010) and the abdominal aorta for the lower limbs (Latham et al., 1985), and 1 cm from the origin of the external carotid artery for the head and neck region (Nowrozani & Zareiyan, 2011) [we here assume the same distance for the internal carotid artery, consistent with its classification as a muscular artery (Rees, 1968)]. Using this, we propose a ‘transition distance index’ (TDI) of an artery as a surrogate marker for its degree of elasticity/muscularity.…”

Label-free assessment of carotid artery biochemical composition using fiber-based fluorescence lifetime imaging

“…Moving along the length of each artery from the heart (caudal region) toward the head (cranial region) there is an arterial narrowing and a distinct transitional zone in which the elastic wall is replaced by a muscular type [ 25 ], resulting in the caudal region of the artery having a larger elastin content and the cranial region a more collagenous structure. Collagen and elastin are the main components responsible for the mechanical behavior of the arterial wall [ 26 , 27 ] and alterations in the collagen to elastin ratio help maintain blood pressure and regulate blood flow across changes in artery diameter [ 25 , 28 ]. An imaging technique that quantitatively assess the anatomical differences in the collagen and elastin content of native artery would provide direct biochemical information and also infer differences in the functional properties of the tissue.…”

Poisoning by Nierembergia veitchii: Effects on vascular smooth muscle cells in the pathogenesis of enzootic calcinosis

“…28,36,37 However, reports on enzootic calcinosis in muscular arteries are uncommon. 46 In muscular arteries, such as the external carotid artery, 30 mineralization is not observed in the intima; it is seen only in the media. In sheep poisoned by Nierembergia veitchii , the intima of external carotid arteries showed hyperplasia without mineralization, and the media was mineralized with large areas of osteochondroid metaplasia in the advanced stages of the disease.…”