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Title: Ultrastructural features of normal rat pulmonary artery and effect of low barometric pressure
Author: Meyrick, Barbara Olive
ISNI:       0000 0001 3396 6619
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1976
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The purpose of the present study was to establish by light microscopy of 1 um sections and by electron microscopy, the changes found in hypertension induced by exposure to a low barometric pressure (hypoxia) for periods up to 52 days and to analyse the changes found in the various structural types of artery. A necessary preliminary to interpret these changes was the study of the normal ultrastructural features of the rat pulmonary circulation, especially the arteries. In addition to the muscular, partially muscular and non-muscular regions of artery, for the first time, a new feature has been described - a thick walled oblique muscular segment - where the muscle is obliquely orientated in the wall which is thicker than expected for diameter. The recognition of this type of artery is of particular importance when assessing pathological increases of medial wall thickness. In addition, using the electron microscope, the 'intermediate' cell has been described in the walls of the non-muscular regions of the partially muscular artery, and the pericyte in the walls of the non-muscular pre-capillary as well as in the alveolar capillary. The 'intermediate' cell seems to represent a cell type that is intermediate both in structure and position between the pericyte and smooth muscle cell. After exposure to hypoxia, the most striking change occurred in the normally non—muscular regions of the artery, where 'new muscle' appeared in the vessel wall. The position of these 'new muscle' cells suggested that they had differentiated from the 'intermediate' cell and pericyte. Additionally, for the wall of the larger muscular arteries, there was hypertrophy of the medial smooth muscle cells and a proliferation of adventitial fibroblasts, both of which were accompanied by increased amounts of connective tissue. Thickened endothelial cells were apparent at all levels of the arterial circulation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available