Histomorphometry of the lower respiratory system of straw coloured fruit bat (eidolon helvum)

The description of microanatomy of the lower respiratory tract (LRT) in the straw coloured fruit bat is scarce. Therefore, the present study is planned at documenting normal histology of the LRT of the bat (E. helvum) found in Nigeria. The tracheal, principal bronchi and lungs were cut at 5 µm thickness sectioned for histomorphology. Tissues from seven (7) bats were utilized in the study. Sections of the LRT were stained with Haematoxylin and Eosin (H & E) stain. The trachea was clearly divided into membranous and cartilaginous portion. The principal bronchi were lined each with a layer of columnar ciliated epithelial cells and below the epithelium was a layer of smooth muscle. The respiratory bronchioles were lined by a low columnar epithelium and continued as alveolar ducts and opened into alveolar sacs. The average diameter of trachea, respiratory bronchiole, alveoli duct and alveoli were 2.82 ± 0.09 µm, 0.50 ± 0.04 µm, 0.47 ± 0.02 µm and 0.17± 0.01 µm respectively. Our findings were compared with similar report in other mammals. This study will help to bridge the dearth of information in this area.