The innervation of the aesthetasc hairs of Panulirus argus

Abstract

ABSTRACT The aesthetasc hairs that occur on the outer ramus of the antennule of Panulirus argus are heavily innervated. Approximately 350 neurones are present at the base of each hair, and dendrites pass up into the hair lumen. These dendrites end one-third of the distance to the hair tip. They are composed of paraciliary structures that extend beyond the surrounding sheath. The hair lumen is in contact with the external environment through a pore at the end of the hair. The sensory cells are surrounded by sheath cells along the axons and as far distally as the sensory cell nucleus. Distally the dendrites are also sheathed by glia and hypodermal cells. The distal region of the sense cell body is not invested, the cell membranes are closely applied one to another and interdigitation occurs.