Sea stars have countless weird and also wonderful adaptations - including some unusual inner systems. Click on any of the labels in this interactive to check out short video clip clips or pictures to learn more.

You are watching: What type of skeleton does a starfish have


Sea stars have many weird and also wonderful adaptations - consisting of some unusual interior systems. Click on any of the labels in this interaction to watch short video clips or images to discover more.

Don’t fubraintv-jp.comet to flip the sea star over and see what’s on top - the dorsal view!


Hard human body plates

Sea stars are invertebrates so they don’t have actually a backbone, yet they do have a skeleton beneath your skin. This endoskeleton is comprised of a complex network of difficult bony plates made of calcium carbonate and also held together by solid flexible tissues.

Acknowledgement: Suhailah J Nassar

Circulatory system

Sea stars have actually a really unusual circulatory system. They perform not pump blood roughly their bodies. Instead, they use seawater and also a complex water vascular system to keep things moving. Their pipe feet, also used because that movement, are crucial part of this circulatory system. Sea stars have actually hundreds of pipe feet on their underside.

Acknowledgement: catalent E. Conlan PhD


A sea star has actually 2 stomachs, the cardiac stomach and the pyloric stomach. It deserve to push the cardiac stomach the end of its mouth, in the centre of the underside, come engulf prey or insert it right into prey (between 2 shells, because that example). The stomach then secretes a powerful digestive enzyme to malfunction the prey.

When the cardiac stomach comes ago into the body, the food in that is transferred to the pyloric stomach.

Acknowledgement: college of Waikato

Obtaining oxygen

Sea stars don’t use gills or lung to breathe. They count on diffusion across surfaces in your body. Because that example, most oxygen is taken increase from water that passes end their tube feet and papulae or skin gills. Skin gills are small projections near the base of the spines, commonly on the topside.

Acknowledgement: college of Waikato

Tube feet


They move fairly slow so we wouldn"t necessarily see them swimming or watch them moving around. However certainly if you were to watch them because that long sufficient you would check out they are really mobile, and they move around using special structures referred to as tube feet, which space like small tentacles with little suckers on the finish of them, and also an separation, personal, instance starfish will have 2 or 3 hundreds of those. For this reason it’s acquired these tiny tentacles, which room on the underside, i m sorry it uses to ubraintv-jp.comanize on to the rock wall or the wharf piling or whatever and also move roughly in a co-ordinated fashion.

Nerve net


They don"t have a central nervous system. They have something referred to as a nerve net, i m sorry is basically just all your nerves space spread end their whole body. However they can still move in a co-ordinated directional manner. So they’ll have parts of your body which room detecting a stimulus, and they’ll relocate towards the or relocate away from the if it’s something they want to walk to or something it is annoying them.

Most sea stars have eyes ~ above the tips of your arms. Learn an ext about this ‘eye spots’ in this blog by Ed Yong.

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To extend learners, look within a sea star to watch the inner operations of an animal very different from united state in this animation, Sea star body plan.