Summarizing Phylum Porifera

Summary

Animals included in phylum Porifera are Parazoans because they do not show the formation of true tissues (except in class Hexactinellida). These organisms show very simple organization, with a rudimentary endoskeleton. Sponges have multiple cell types that are geared toward executing various metabolic functions. Although these animals are very simple, they perform several complex physiological functions.

Glossary

amoebocyte

sponge cell with multiple functions, including nutrient delivery, egg formation, sperm delivery, and cell differentiation

choanocyte

(also, collar cell) sponge cell that functions to generate a water current and to trap and ingest food particles via phagocytosis

gemmule

structure produced by asexual reproduction in freshwater sponges where the morphology is inverted

invertebrata

(also, invertebrates) category of animals that do not possess a cranium or vertebral column

mesohyl

collagen-like gel containing suspended cells that perform various functions in the sponge

osculum

large opening in the sponge’s body through which water leaves

ostium

pore present on the sponge’s body through which water enters

pinacocyte

epithelial-like cell that forms the outermost layer of sponges and encloses a jelly-like substance called mesohyl

Porifera

phylum of animals with no true tissues, but a porous body with rudimentary endoskeleton

sclerocyte

cell that secretes silica spicules into the mesohyl

spicule

structure made of silica or calcium carbonate that provides structural support for sponges

spongocoel

central cavity within the body of some sponges