Muscle fibres of the locust extensor tibiae (jumping muscle) were examined by interference microscopy and by electron microscopy. The electrical responses of single fibres and the mechanical responses of bundles or selected regions to the nerve fibres were examined. Four axons innervate the muscle: fast (FETi), slow (SETi), common inhibitor (CI) and dorsal unpaired median (DUMETi). Their distri...

Elastic fibres are essential extracellular matrix macromolecules comprising an elastin core surrounded by a mantle of fibrillin-rich microfibrils. They endow connective tissues such as blood vessels, lungs and skin with the critical properties of elasticity and resilience. The biology of elastic fibres is complex because they have multiple components, a tightly regulated developmental depositio...

Crayfish commonly evade capture by darting backwards when one tries to pick them up or otherwise disturbs them. They do this by sharply flexing the abdomen, the tail fan acting as a paddle; at the same time they streamline themselves by thrusting their appendages forward. Like many other escape and startle reflexes throughout the animal kingdom, this one is exceedingly labile. A crayfish held b...

Considerable analysis has been made of the properties of individual interneurons in the crayfish central nervous system. Most of the investigations have dealt with the reactions of interneurons to specific sensory stimuli. It has been possible to characterize many of the interneurons both in terms of the sensory information they carry and their position within the nerve cord. Thus the crayfish ...

Objective: To assess the thickness and color of collagen fibres in various odontogenic cysts for its possible role in expansion. Study design: 49 cases of 4 types of odontogenic cysts and 5 normal mucosal tissues were selected as the study and the control group respectively. All slides were stained with both Hemotoxylin and Eosin and the picrosirius red stain. The thickness of collagen fibres w...

Since Overton's finding on muscle (1), examination on the effect of Na deficient media upon the nervous function has been a centre of interest (27). The blocking concentration, or the minimal concentration required for conduction, has been said to be 10-15% of that of the normal Ringer for nonmyelinated fibres of the Crustacean (4) and 0.011 M for myelinated fibres of the frog (5), which are al...

Neuropeptide tyrosine (NPY), a newly discovered peptide known to modulate blood vessel diameter and smooth muscle tone, has been found in many mammalian organs. Its distribution is similar to that of sympathetic nerve fibres and NPY immunoreactivity has been found in noradrenergic ganglion cells. In a study of the respiratory tract of four mammalian species--man, cat, guinea pig, and rat--NPY i...