Chapter 4- Poriferans and Placozoans Flashcards
Terms and Definitions
The central cavity within a sponge where water flows.
Spongocoel
Specialized cells in sponges that have flagella and line the spongocoel, creating water currents and filtering food.
Choanocytes
Another name for choanocytes, highlighting their structure that resembles a collar around the flagellum.
Collar cells
The gelatinous layer found between the outer layer (pinacoderm) and the inner layer (choanocyte layer) of sponges.
Mesohyl
Amoeboid cells in sponges that can differentiate into various cell types and are involved in digestion, regeneration, and producing gametes.
Archaeocytes
Structural elements made of silica or calcium carbonate, providing support and shape to sponges.
Spicules
A type of flexible, fibrous protein that forms part of the skeleton in some sponges, providing structural support.
Spongin
Cells within sponges that secrete spicules.
Sclerocytes
Cells that produce spongin fibers.
Spongocytes
Dormant structures produced by freshwater sponges that can survive harsh environmental conditions.
Gemmules
The requirement of a period of cold or certain environmental conditions to promote the hatching of gemmules.
Vernalization
Flattened contractile cells that form the outer layer of sponge tissue, contributing to the overall shape of the sponge.
Pinacocytes
The outermost layer of cells in sponges, composed mainly of pinacocytes.
Pinacoderm
A layer of extracellular matrix that supports epithelial cells in many organisms, though sponges lack a true basal lamina.
Basal lamina
Small openings in the sponge body through which water enters.
Ostia
Larger openings through which water exits the spongocoel.
Oscula
A class within the phylum Porifera characterized by sponges with calcium carbonate spicules.
Class Calcarea
Referring to an organism that has both male and female reproductive organs and can produce both sperm and eggs.
Hermaphroditic
A type of sponge embryo that develops into a hollow blastula stage.
Coeloblastula
A free-swimming larval stage in some calcareous sponges, characterized by flagellation at one end.
Amphiblastula
An embryo that becomes solid after initially being hollow.
Stereoblastula
A type of larval stage in sponges that is characterized by having numerous flagellated cells.
Parenchymella
Another term for parenchymella, emphasizing its developmental stage.
Parenchymula
