Extrinsic Nerve Fibers Research Articles

Degeneration analysis of the efferent nerves to the urinary bladder in the cat

The extrinsic efferent nerve fibres to the urinary bladder in the cat were studied by secondary degeneration after transection of the seventh lumbar, all three sacral and the first coccygeal ventral roots of spinal nerves and after extirpation of both hypogastric ganglia. Under the electron microscope, degenerated nerve fibres of spinal origin could be observed in the trigone region among the ganglion cells and all layers and in the different areas of the urinary bladder wall. These degenerated nerve fibres containing mainly clear vesicles, 30-60 nm in diameter, and a few 80- to 120-nm granular vesicles were situated in synapsing contacts on the surface of the local nerve cells and in synapsing with other probably local nerve processes. After extirpation of the hypogastric ganglia several degenerated nerve fibres could be found along the blood vessels and lymph vessels in all layers. However, occasionally on the surface of the local nerve cells degeneratd nerve fibres could also be found. 2 months after both interferences most of the nerve fibres and synapses remained unaffected. According to these observations the extrinsic efferent nerve fibres and synapse seem to have a modulatory effect on the local ganglia. The large amount of the local intact synapses suggests that the micturition reflex is not a spinal but a local peripheral reflex.

Special muscle cells and their innervation in the mammalian small intestine.

The innermost layer of the circular musculature of the ileum of the guinea-pig, mouse, rat, rabbit, cat and dog is made of special small and dark muscle cells (sd cells), which can be identified by light and electron microscopy. These cells have a higher surface to volume ratio than ordinary muscle cells. They show all the organelles of smooth muscle cells and are in close relationship with a great number of extrinsic and intrinsic nerve fibres. They send numerous thin cytoplasmic processes towards the bulk of the circular layer, but nexuses between the sd cells and ordinary muscle cells are not found. It is suggested that some of the nerve fibres in this part of the circular layer are motor, setting the sd cells to a given length, and some are afferent in luminal pressure.

2. Neurohistoloical Studies of the Anus among Japanese

The nerve supply of the lining tissue of the anal canal had three origins.The first was the MEISSNER'S plexus, which laid only upper end of the anal canal in foetus and newborn.The second was extrinsic nerve fibers coming from the pelvic space to pass through the longitudinal muscle and pass through/under the internal sphincter. The fibers were numerous in foetus but diminished with getting older.The third was extrinsic nerve fibers which passed through the external sphincter, under the internal sphincter, and went upward as far as the dentate line making nerveplexus and sensory endings.Sensory endings consisted of free nerve ending, organized ending and hair plexus. Free endings were found in foetus as well as in adult. Organized endings were found in subjects aged of four years and adult: many of them were "glomerular type" endings and a few genital corpuscle. Special baroreceptors such as arborised ending (SUNDER-PLASSMANN) were found especially adjacent to the hemorrhoidal plexus. At anal valve, some nerve fibers, showed extensive neurofibrillar swelling which presumably play some role to extend the sensory area of nerve element.Out of the intersphincteric groove was shown to be innervated by fibers which passed under the external sphincter.

1. Neurohistological Studies of the Anus among Japanese

The nerve supply of the lining tissue of the anal canal had three origins.The first was the MEISSNER'S plexus, which laid only upper end of the anal canal in foetus and newborn.The second was extrinsic nerve fibers coming from the pelvic space to pass through the longitudinal muscle and pass through/under the internal sphincter. The fibers were numerous in foetus but diminished with getting older.The third was extrinsic nerve fibers which passed through the external sphincter, under the internal sphincter, and went upward as far as the dentate line making nerveplexus and sensory endings.Sensory endings consisted of free nerve ending, organized ending and hair plexus. Free endings were found in foetus as well as in adult. Organized endings were found in subjects aged of four years and adult: many of them were glomerular type endings and a few genital corpuscle. Special baroreceptors such as arborised ending (SUNDER-PLASSMANN) were found especially adjacent to the hemorrhoidal plexus. At anal valve, some nerve fibers, showed extensive neurofibrillar swelling which presumably play some role to extend the sensory area of nerve element.Out of the intersphincteric groove was shown to be innervated by fibers which passed under the external sphincter.

ELECTROPHYSIOLOGICAL STUDY ON THE INTRINSIC NERVE PLEXUS OF STOMACH

As a rule visceral smooth muscle contains relatively abundant nervous elements. In the stomach, nerve cells lie between the circular and longitudinal muscle layers and in the submucosa. Besides these intrinsic nerve cells stomach has extrinsic nerve fibers too, and both constitute the intricate networks which are called myenteric plexus (Auerbach's plexus) and submucous plexus (Meissner's plexus) respectively. Since the experimental investigations made by Magnus (1) (2) on the interrelation between the intrinsic nerve plexus and the automaticity of digestive tract, the functional role of this plexus of digestive tract became one of the interesting problems in the physiology. Pharmacological, histological and surgical studies hitherto were made by many workers (3-11), however failed to demonstrate clearly the activity of intrinsic plexus. The author attempts to make clear the functional property of the intrinsic nerve cells by studying their spontaneous electrical discharges using a microelectrode and high grade amplifier. This paper is dealing mainly with the properties of the spontaneous activity of intrinsic nerve cells concerning their functional characteristics will be reported later.

A note on the connections, in the mammalian myenteric plexus, between the enteric neurones and extrinsic nerve fibers

A note on the connections, in the mammalian myenteric plexus, between the enteric neurones and extrinsic nerve fibers