Caudal Morphology of the Knob-Tailed Geckos, Genus Nephrurus (Reptilia, Gekkonidae), With Special Reference to the Tail Tip

1987 ◽  
Vol 35 (6) ◽  
pp. 541 ◽  
Author(s):  
AP Russell ◽  
AM Bauer

The tail of lizards in the Australian gekkonid genus Nephrurus bears a characteristically expanded distal tip, the caudal knob. Anatomical and histological investigation of the knob reveals it to be an integumentary derivative with a massively hypertrophied dermal component. The knob's structure indicates that it is probably used to monitor the environment by detecting mechanical stimuli via the profuse array of sensilla on its surface. The vascular supply to it suggests that the knob may also be involved in thermoregulation.

2003 ◽  
Vol 78 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Aki Nihei ◽  
Kayo Hagiwara ◽  
Motoshi Kikuchi ◽  
Takashi Yashiro ◽  
Yuichi Hoshino

1993 ◽  
Vol 37 (1) ◽  
pp. 144-158 ◽  
Author(s):  
Masahito Sawada ◽  
Haruka Kusakari ◽  
Osamu Sato ◽  
Takeyasu Maeda ◽  
Yoshiro Takano

Author(s):  
C. W. Klscher ◽  
D. Speer

Dupuytren's Contracture is a nodular proliferation of the longitudinal fiber bundles of palmar fascia with its attendant contraction. The factors attributed to its etiology have included trauma, diabetes, alcoholism, arthritis, and auto-immune disease. The tissue has been observed by electron microscopy and found to contain myofibroblasts.Dupuytren's Contracture constitutes a scar, and as such, excessive collagen can be observed, along with an active form of fibroblast.Previous studies of the hypertrophic scar have led us to propose that integral in the initiation and sustenance of scar tissue is a profusion of microvascular regeneration, much of which becomes and remains occluded producing a hypoxia which stimulates fibroblast synthesis. Thus, when considering a study of Dupuytren's Contracture, we predicted finding occluded microvessels at or near the fascial scarring focus.Three cases of Dupuytren's Contracture yielded similar specimens, which were fixed in Karnovskys fluid for 2 to 20 days. Upon removal of the contracture bands care was taken to include the contiguous fatty and areolar tissue which contain the vascular supply and to identify the junctional area between old and new fascia.


Author(s):  
Wen-lung Wu

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.


2020 ◽  
Vol 134 (17) ◽  
pp. 2399-2418
Author(s):  
Yoshito Yamashiro ◽  
Hiromi Yanagisawa

Abstract Blood vessels are constantly exposed to mechanical stimuli such as shear stress due to flow and pulsatile stretch. The extracellular matrix maintains the structural integrity of the vessel wall and coordinates with a dynamic mechanical environment to provide cues to initiate intracellular signaling pathway(s), thereby changing cellular behaviors and functions. However, the precise role of matrix–cell interactions involved in mechanotransduction during vascular homeostasis and disease development remains to be fully determined. In this review, we introduce hemodynamics forces in blood vessels and the initial sensors of mechanical stimuli, including cell–cell junctional molecules, G-protein-coupled receptors (GPCRs), multiple ion channels, and a variety of small GTPases. We then highlight the molecular mechanotransduction events in the vessel wall triggered by laminar shear stress (LSS) and disturbed shear stress (DSS) on vascular endothelial cells (ECs), and cyclic stretch in ECs and vascular smooth muscle cells (SMCs)—both of which activate several key transcription factors. Finally, we provide a recent overview of matrix–cell interactions and mechanotransduction centered on fibronectin in ECs and thrombospondin-1 in SMCs. The results of this review suggest that abnormal mechanical cues or altered responses to mechanical stimuli in EC and SMCs serve as the molecular basis of vascular diseases such as atherosclerosis, hypertension and aortic aneurysms. Collecting evidence and advancing knowledge on the mechanotransduction in the vessel wall can lead to a new direction of therapeutic interventions for vascular diseases.


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