BIOL 1202 Chapter : BIO1202 T4
Document Summary
Sponges are sessile and have porous body and choanocytes (concept 33. 1) Only organized at the cellular level - no tissues. Lack true tissues and organs - organized at cellular level. Asymmetrical body plan - grow dependent on the environmental conditions. Porocytes - dough nut shaped cells that span the body wall. Chanocytes: line the spongocoel, movement of flagella sets up water flow. Chaonocytes: trap food and ingest it by phagocytosis pass it along to ameobocytes. Ameobocytes :transport nutrients to other cells, secretes spicules. Spicules - skeletal elements that determine the structure. Cnidarians have radial symmetry, a gastrovascular cavity and cnidocytes (concept. Wide range of sessile and floating forms including jellyfish, corals, and hydras. Diploblastic - two tissue layers (outer epidermism and inner endodermis) Body plan is a sac with a central gastrovascular cavity. Single opening serves as both mouth and anus (nutrients absorbed and waste deposited from same opening)
