aboral
toward or on the opposite side or end from the mouth. the aboral surface of a sea star is the functional upper surface
amburacral groove
the fissure along the midline of the oral surface of each arm of a sea star, where most of the tube feet are housed
ampulla
the bulb atop each tube foot. the ampulla lies within the coelom while the attached tube foot projects through the body wall
arm
one of the lateral projections from the central disc of a sea star of brittle star usually occurring in multiples of five; also called a ray
central disc
the central portion of a sea star from which the arms or rays radiate
dermal branchiae
papulae; tiny extensions from the sea star's coelomic cavity that project through the body wall. due to their function in gas exchange, they are sometimes called skin gills
gonad
a reproductive organ that produces sex cells
intestine
in sea stars the short tube connecting the pyloric stomach and the anus
madreporite
sieve plate; the intake for the water vascular system of a sea star; found off center in the central disc
oral surface
the functional lower surface of a sea star where the mouth is located
ovary
female gonad; produces ova
pedicellaria
a tiny claw or pincer on the external surface of an echinoderm
radial canal
portion of the water vascular system that runs from the ring canal along the midline of each arm of a sea star
radial symmetry
arrangement of body parts around a central axis
ring canal
portion of the water vascular system that encircles the mouth; radial canals branch from it
sieve plate
madreporite; intake to the water vascular system in echinoderms
stone canal
calcified portion of the water vascular system that connects the sieve plate with the ring canal
testis
one of the paired male gonads that produces sperm
tube feet
podia; extensions from echinoderm water vascular system; used in locomotion, food-gathering, and respiration
water vascular system
system of tubes derived from the coelom, unique to echinoderms, enabling them to use hydraulic pressue to aid in food gathering and/or locomotion