BI256 Lecture Notes - Lecture 10: Gastrovascular Cavity, Cnidaria, Zooid
Document Summary
Lecture 10 flatworms part ii - gnathifera and ectoprocta. Ciliated crown (corona) important for both feeding and locomotion. Adapted to many ecological conditions mainly freshwater some brackish. No ciliated, syncytial epidermis with secreted cuticle. Complete digestive system (mouth to anus), salivary and gastric glands. Dioecious (males smaller than females), some males unknown. Females with paired ovaries, parthenogenic reproduction in some. Excretory system has pair of protonephridial tubules with flame cells that empty to common bladder. Pulsating motion drains bladder into cloaca which also serve intestines and oviduct. Osmoregulation is important in both freshwater and marine species; because water enters by the mouth during feeding. A bilobed brain is dorsal to the mastax with paired nerves leading off to the organs. Sensory organs include eyespots, sensory bristles and papillae, and ciliated pits and dorsal antennae. Water current created by coronial cilia draws food towards the mouth and sort out larger unsuitable particles in suspension feeders.
