coelom
Mesoderm-lined space
A coelom is the fluid-filled body cavity between the digestive tract and outer body wall in many animals.
This internal space, lined with tissue derived from the mesoderm, houses and protects organs while allowing them to move independently.
Humans, insects, and earthworms are coelomates; jellyfish and flatworms lack this cavity entirely.
Empty space within
- mesodermEmbryonic tissue forming muscles
- peritoneumMembrane lining the abdomen
- visceraAbdominal organs collectively
- fluid-filledContaining liquid matter
hydrostatic · body cavity · membrane · lining · serous · parietal · visceral · thoracic
Fluid-filled cavity providing support
- locomotionAbility to travel independently
- peristalsisInvoluntary digestive muscle waves
- burrowingDigging to create shelter
- movementChange in position
support · pressure · turgor · contraction · flexibility · cushioning · circulation · waste removal
Embryo forms primary layers
- mesodermEmbryonic tissue forming muscles
- morulaSolid embryonic cell mass
- gastrulaCup-shaped early embryo
- embryonicAt earliest developmental stage
development · formation · differentiation · organogenesis · primitive · folding · splitting · pouching
Ringed-body worm phylum
- mollusksSoft-bodied invertebrates, often shelled
- arthropodsJointed-limb invertebrates
- echinodermsSpiny-skinned marine invertebrates
- nematodesCylindrical unsegmented worms
earthworm · segmented · cephalopods · reduced · modified · sinuses · lacunae
Organism's fundamental structural arrangement
- bilateralInvolving two parties
- symmetryInvariance under transformation
- taxonomicOf systematic categorization
- phylogeneticOf evolutionary relationships
cavity
Empty space within
- mesodermEmbryonic tissue forming muscles
- peritoneumMembrane lining the abdomen
- visceraAbdominal organs collectively
fluid-filled · hydrostatic · body cavity · membrane · lining · serous · parietal · visceral · thoracic · abdominal
hydrostatic skeleton
Fluid-filled cavity providing support
- locomotionAbility to travel independently
- peristalsisInvoluntary digestive muscle waves
- burrowingDigging to create shelter
movement · support · pressure · turgor · contraction · flexibility · cushioning · circulation · waste removal · reproduction
gastrulation
Embryo forms primary layers
- mesodermEmbryonic tissue forming muscles
- morulaSolid embryonic cell mass
- gastrulaCup-shaped early embryo
embryonic · development · formation · differentiation · organogenesis · primitive · folding · splitting · pouching · invagination
annelids
Ringed-body worm phylum
- mollusksSoft-bodied invertebrates, often shelled
- arthropodsJointed-limb invertebrates
- echinodermsSpiny-skinned marine invertebrates
nematodes · earthworm · segmented · cephalopods · reduced · modified · sinuses · lacunae
body plan
Organism's fundamental structural arrangement