CELL BIOLOGY
EVISCERATION
A novel feature of holothurians is the ability to eviscerate. Evisceration in holothurians is a complex process. It involves a rapid softening of the attachment ligaments of the viscera and of the tendons of selected muscles to the cloaca, the mesenteries, and the body wall; an intense, localized softening of the body wall or the cloaca; and a contraction of the muscles that easily stretches and ruptures the weakened structures, expelling the disconnected viscera [2]. To counter this destructive defence mechanism, holothurians have an exceptional regenerative capacity. Studies have shown that visceral organs can regenerate in as rapidly as seven days, though most species require around one month to complete the process.
MUTABLE CONNECTIVE TISSUE
An astounding feature of echinoderms is the presence of catch tissue, or mutable connective tissue. This special tissue allows echinoderms to reverse the rigidity of their skin and general connective tissues [14]. |