starfish lab

radial

five

small, round hard plate on top of central disc; water enters through this into the vascular system

small opening right next to the madreporite; for excretion following digestion

on upper surface of starfish; protect the starfish and are part of internal skeleton

between each spine; pores that allow the starfish to take in oxygen for cellular respiration

at the tip of each arm

in the center of the disc

a ring of oral spines surrounds the mouth

groove that extends down the underside of each arm

inside each groove; part of the water vascular system; aid in movement and feeding; attached to a zipper-like ridge that extends the length of the ray/arm

bulb-like top of a tube foot; sac that works like the top of an eyedropper to create suction; bottom of the tube foot is a sucker

digestive glands that make enzymes to digest food in the stomach

under the central disc

testes/ovaries; underneath the pyloric caeca; may be small if starfish is not breeding

skeletal plates embedded in the soft body wall

rubs down center of each arm; tube feet are attached to this

circular canal that five lateral canals are connected to in central disc

short canal; leads from the ring canal to madreporite, where water enters

rudimentary; lacks a brain; contains central nervous system in form of a nerve ring; similar location to the ring canal

seen when gonads are removed; system of canals in which seawater (instead of blood in circulatory system) circulates throughout the starfishs body

rely on fluid (mostly water) that is always under pressure; constant volume of fluid in an enclosed body space called the coelom or coelomic cavity; tube feet of starfish rely on hydrostatic skeleton to enable the organism to move

underside

animalia

echinoderm

asteroidea

oral surface

aboral

oral

regenerates

The starfish digestive system involves dual stomachs, the cardiac stomach, and the pyloric stomach. The unique adaptation is that they can evert their stomach out of their mouth to digest food externally before retracting it back into their body.

madreporite > stone canal > ring cansl > radial canal > lateral canal

By moving water from the vascular system into the tiny feet, the sea star can make a foot move by expanding it. Movement in a hydrostatic skeleton is provided by muscles that surround the coelom

annelida have a central nervous system while echinoderm nervous system has a circumoral nerve ring connected to five radial nerve cords

most oxygen is taken up from water thst passes over their tube feet snd papulae or skin gills. earthworms take in oxygen through their skin

nerve ring, eyespot, radial nerves

pyloric caeca, mouth, stomach

madreporite and tube feet

gonads

spines

madreporite and stone canal