Quantitative studies of the aortic bodies of the cat. I. Point-counting analysis of tissue components.
Electron micrographs of cat aortic bodies were submitted to point-counting analysis to determine the volume/volume densities (vv%) of general tissue components. Paraganglia, enclosed by a perineural sheath (endoneural paraganglia), exhibit a significantly higher density of specific tissue elements (type-I cells, type-II cells, nerves) than those which covered by fibroblasts (exoneural paraganglia). Additional criteria which allowed distinction of these types of aortic bodies were not evident in this study. On average, type-I cells occupied 27.8 vv% if related to the entire organ, or 35.6 vv% if related to the blood vessel-free space. Comparing our data with those reported for the carotid body, we found an about twofold amount of type-I cells within aortic bodies. The relevance of this finding is discussed with respect to the known different electrophysiological properties of carotid and aortic body arterial chemoreceptors.
D000818:Animals; D001016:Aortic Bodies / Q000098:blood supply / Q000166:cytology / Q000648:ultrastructure*; D002415:Cats; D008854:Microscopy, Electron; D010234:Paraganglia, Nonchromaffin / Q000648:ultrastructure*