A study of the innervation of the lamina muscularis mucosae in the intestine of sheep

Ariana, (1997) A study of the innervation of the lamina muscularis mucosae in the intestine of sheep. Masters by Research thesis, Murdoch University.

Abstract

A study on the innervation of the lamina muscularis mucosae of the sheep intestine has been undertaken. This study aimed to provide morphological information on the types of neuron, axonal ending and glial cell within ganglia associated with the lamina muscularis mucosae and the possible relationship between these ganglia with this smooth muscle layer.

Nineteen Merino sheep were used and the ileum of these exprimental animals was processed in a routine manner for the light and electron microscopy.

This study showed that the ganglia associated with the lamina muscularis mucosae were similar to other enteric ganglia in that they did not contain blood vessels and intraganglionic connective tissue. The neurons within these ganglia could be classified into 4 types according to their relationship with the satellite cells, cell body profiles and the distribution of cytoplasmic organelles. Some neurons contained a proportion of granular vesicles and may correspond to the small intensely fluorescent cells. The axonal endings contained a proportion of 1) small, agranular and granular vesicles and large granular vesicles, 2) small granular and large granular vesicles, 3) small agranular and large granular vesicles and 4) flattened small agranular and large granular vesicles. These suggested the presence of adrenergic, cholinergic and peptidergic nerves.

No neurons were seen within the lamina muscularis mucosae. Bundles of unmyelinated nerve fibres on the submucosal surface of this smooth muscle layer were often seen. Axonal endings embedded in Schwann cell cytoplasm within the muscle fibres were sometimes seen. However, no neuromuscular junctions were observed. Axonal endings within the lamina muscularis mucosae contained similar types of vesicles to those seen in the ganglia associated with this smooth muscle layer.

The presence of similar types of axonal ending within the lamina muscularis mucosae raises the possibility that this smooth muscle layer, in addition to myenteric and submucosal plexus innervation, may receive nerve fibres which are projected by the ganglionic neurons associated with this smooth muscle layer. Since the presence of axonal endings within the lamina muscularis mucosae is rare, it may also be directly controlled by neurotransmitters released from the adjacent axonal endings. Although the function of this smooth muscle layer is still unclear, the contraction ability of this smooth muscle is predicted to have an influence to the mucosal secretion and absorption activities.

Item Type:	Thesis (Masters by Research)
Murdoch Affiliation(s):	Division of Veterinary and Biomedical Sciences
Notes:	Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s):	Creed, Kate E. and Cook, Robert
URI:	http://researchrepository.murdoch.edu.au/id/eprint/51706

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