Ultrastructural morphometric observations on the extramural aortico-pulmonary bodies of the domestic fowl.

The extramural aortico-pulmonary bodies of the domestic fowl were analysed in electron micrographs by point-counting morphometry. The Type I cell constituted about 34% of the total volume of the parenchyma, whereas the supporting cells (Type II cells, pericytes and Schwann cells) constituted about 26%. The blood capillaries occupied the lowest volume density of about 5%. The mitochondria and the dense-cored vesicles occupied about the same volume (8%) of the Type I cell cytoplasm. The results obtained in the present study are compared with other similar studies on the aortic and carotid bodies of mammals.