Lecture 4: Porifera and Placozoa

Question 1

mesohyl (mesenchyme)

Answer 1

area between the two layers of sponge

has spongin(fibrous form of collagen), polypeptides, and other wandering cells and skeletal elements

Question 2

mesoglea

Answer 2

extracellular matrix

Question 3

totipotent

Answer 3

• trait of cells in sponges
• no musculature, tissues, organs, nerves

can differentiate into any cell type (archeocytes)

Question 4

spongocoel

Answer 4

large middle cavity found in porifera body plan

central cavity

Question 5

ostium

Answer 5

singular ostia

pores that draw water in to the central cavity (or spongocoel) of the sponge

Question 6

choanocyte/collar cells

Answer 6

circulate water, capture food and sperm

have a flagellum and collar of microvilly

Question 7

amoebocyte (archaeocyte)

Answer 7

• digest food (intracellular)
• makes both gametes
• eliminate waste, keeps ostia free of debris
• recognition
• bioerosion

known for totipotency

Question 8

porocyte

Answer 8

alongside the ostia structure, it allows water into sponge

Question 9

pinacocyte

Answer 9

epithilial-like, cells of the pinacoderm layer

Question 10

pinacoderm/choanoderm

Answer 10

the outer layer of the sponge/inner layer of the sponge

Question 11

spicule

Answer 11

provides structural support in sponges

skeletal elements of a sponge, composed of calcium carbonate or silica

Question 12

asconoid

Answer 12

simplest body plan in sponges

one large osculum with large incurrent canals

Question 13

syconoid

Answer 13

intermediate body plan in sponges

has consistently shaped incurrent canals, but more complex than ansconoid, connect to smaller cavities before spongocoel

Question 14

leuconoid

Answer 14

most complex body plan in sponges

structure similar to brain folds/shape, complex framework of thinner incurrent canals traveling to multiple bodily cavities

Question 15

syncytial

Answer 15

means no pinacoderm is present

Question 16

gemmule

Answer 16

dessication resistant stage in porifera reproduction

Question 17

parenchymula larva

Answer 17

one type of larvae found in Porifera, demosponges

motile

envelope of flagellated cells surrounding internal mass of cells

Question 18

amphiblastula larva

Answer 18

one type of larvae found in porifera

motile

oval shape, middle cavity, half flagellated cells other half round without flagella

Question 19

osculum

Answer 19

where water travels out within a sponge

Question 20

scletocytes

Answer 20

cells in mesohyll that secrete spicules, skeletal element