Figure 7
Attachment elements of the sensory organs in the tibia. (ai–iii) Phase contrast micrographs of CTO viewed from anterior showing insertion of IO dendrites in the IO/CAH mass. Sections move from anterior tibial wall (ai) to medial region of tibia (aiii). Note different planes of dendrite innervation into the IO/CAH mass for the IO and CAH. (b) Reconstruction of tibia from confocal stack of lateral (anterior) view of eosine-stained preparation showing the morphology of the SGO and IO/CAH-masses. Sections move from anterior to medial, showing the thinning of the IO/CAH mass. (c) µCT reconstruction of the foreleg tibia in transverse section, looking proximally and showing the SGO mass spanning the tibia with fine suspensory extensions along the anterior margin (white arrowheads). The IO/CAH mass is linked to the tracheae by connective tissue (white arrow). A thin septum connects the anterior and posterior tracheae (empty arrow) and separates the dorsal and ventral hemolymph channels. (d) µCT reconstruction of the foreleg tibia in transverse section at the level just distal to that in (c). The thick IO/CAH mass is attached along its full length to the anterior tibial wall, but shows only indirect association with tibial tracheation. (e) µCT of the midleg tibia. The elongated lamellar structures across the surface of the SGO mass attach to the posterior tibial wall via fine extensions (white arrowheads), as revealed by digital erosion of overlying tissue. Part of the IO/CAH mass is connected to the posterior trachea (white arrow). (f) Transverse view of the SGO with overlying tissue eroded away to show the lamellar layer (hatched line) which gives rise to thin attachment strands on the anterior side and posterior side of the tibial wall (shown here; arrow). Abbreviations: at, anterior trachea; CAH, crista acustica mass; dhl, dorsal hemolymph channel; IO, intermediate organ; pt, posterior trachea; SGO, subgenual organ; SGO mass, subgenual organ mass; vhl, ventral hemolymph channel.
