ZOO-3713C Study Guide - Midterm Guide: Dorsal Nerve Cord, Ventral Nerve Cord, Deuterostome
Document Summary
Deuterostomy: the first invagination, the blastopore, becomes the anus. Radial cleavage: each cell division creates an equal sized cell; symmetrical cleavage. Pharyngeal slits & pharyngeal pores that lead to them and can be seen on the body. Pharyngeal slits: perferations in the wall of the pharynx that allow water to flow through. Dorsal hollow nerve cord: dorsal is thicker than ventral & on top of the body. The primitive condition is the ventral nerve cord, the derived is the dorsal nerve cord; hemichordates have both. Notochord & post anal tail in the larval stage. It is a flexible, rod like backbone that is homologous to the intervertebral discs in vertebrates. Endostyle: longitudinal (on the ventral side opposite of tube) ciliated groove on the pharynx (giant grenade looking thing) that makes mucus and collects food particles. Dorsal carries oxygenated blood from the pharynx to the tissues. Myomeres: skeletal muscle separated by connective tissue & attach to the notochord (at the top)