Abstract
The intestinal system of Ixodes ricinus is assembled by several elements of different morphological origin, i.e. the preoral canal (formed by chelicerae and hypostome), the mouth opening (covered by the labrum), the pharyngeal valve (with contributions of the ectodermal pharynx and the labrum), the ectodermal pharynx (with the precerebral suction pump), the ectodermal esophagus, the endodermal midgut (consisting of the stomach, numerous midgut diverticula, and the rectal sac), the ectodermal hindgut, and the anal aperture.
Ixodes ricinus, like other ixodid ticks, is a temporary, blood sucking ectoparasite. The intestinal system of adult females can accommodate an enormous volume of blood. The intestinal system shows a number of remarkable morphological adaptations to the accomodation of such large blood volume and the cellular components undergo considerable changes in cell morphology and functioning.