Module 3.1: Porifera Flashcards
General Characteristics of Porifera
(SAPAMA)
- Sessile adults; free-swimming flagellated larvae
- Asymmetrical (or Radial symmetry)
- Pore-bearing + canals & chambers that form unique water currents
- Aquatic
- Asexual reproduction via bud / gemmule formation; sexual reproduction via egg & sperm
- Multicellular
Choanocytes structure, function, location
Structure: flagellated cells with microvilli collars
Function: Produce water current + nutrient absorption
Location: Lining the spongocoel (or the canals in a synconoid; or the chambers in a leuconoid)
Pinacoderm
Outermost layer of cells of the Phylum Porifera, equivalent to the epidermis
Archaeocytes
- Digest food captured by choanocytes (intercellular digestion)
- May give rise to sperm or egg
- Secrete supporting elements in mesohyl
Sclerocytes
Secrete spicules – supporting elements
Spongocytes
Produce spongin fibers
Collencytes
Secrete fibrillar collagen
Pinacocytes
Flattened contractile cells that form the pinacoderm
Mesohyl / mesenchyme
Gelatinous ECM of the sponge (non-living layer that contains the cells)
Spicules
Rigid (calcareous or siliceous) and/or fibrous (spongin –collagen fibril) skeletal
framework of the sponge
Vernalization
State of dormancy during unfavorable conditions
Adaptations of Gemmules
- Tissue regression –compact cellular mass with covering; can reactivate
- Regeneration –reorganization of the wounded portion
- Somatic embryogenesis –involves complete reorganization of structure and functions of cells/tissue
Pinacoderm lacks a _____ ______
Basal Membrane; makes it a functional epithelium
Pinacoderm functions
- Prevents small solutes from entering the spongocoel
- Allows minor to major shape change
- Regulates water flow via mycotes
Term for the site of entry and exit of water
Entry: Ostia
Exit: Osculum
