The Skeletal System

BY Olivia Collings

A human baby only has over 300 bones. But an adult only has 206!


The skeletal system is on the outside of their body. Therefore it is an exoskeleton. It has features like segmentation, this allows the prawn to move but not to the extent of our skeletal system. The exoskeleton provides protection for the prawn, it protects the organs and muscles on the inside. It keeps the interior in shape so it doesn't ooze. Other animals that have an exoskeleton are arachnids (spiders), insects, bugs. The prawn's exoskeleton is very different to our skeleton; their exoskeleton is obviously on the outside of their body when ours is on the outside, their exoskeletons are made from chitin (ky-ton) but ours are made of bone. This exoskeleton provides an advantage that we don't have, their protection is on the outside of their body whereas our protection is on the inside of our bodies, this makes us alot more vulnerable when attacked. Like any other living creature, the prawn grows. The exoskeleton doesn't grow very much therefore they have malt their exoskeleton, they are vulnerable or a period of time when the exoskeletons are strengthening again. Their exoskeleton is made from chitin (ky-ton) which is the substance that makes up cells walls in fungus (mushrooms ect.)


Worms have a hydroskeleton. This means their skeletons aren't made of a hard substance like ours or the prawns. It is instead made of fluid. Inside this fluid-filled canal, the water will swoosh to one side and the body will then follow. Working sort of like a slinky.

Worms have a hydroskeleton


Cuttlefish have an endoskeleton (interior), it is a very sparse (not dense), lightweight and helps them float in the water. The cuttlebone provides structure to the fish, without it they would simply flop. The cuttlebone is majorly made from calcium carbonate to provide strength and protection.

Cuttlefish can change the colour of their skin in less than a second to blend in


Obviously, our skeletons are in the core of our body, endoskeleton. The skeletal structure of human is a very complex network of bones and cartridge. Our skeleton gives us strength and structure. With out it we would simply fall into a pile of mushy skin and organs. In the core of our main bones; spine, skull, pelvis ect. Contains bone marrow, a substance that creates the components in our blood. Our bones are made from calcium phosphate, a substance that hardens the bones. Collagen, a material that provides elasticity. Blood vessels run throughout the bones to provide the essential nutrients. When we are born we have many little bones, some that are made entirely from cartilage. When we grow older the little bones fuse together to make larger bones and the cartilage turns into bone. Other animals that have this kind of skeleton include; mammals, most reptiles and most fish. (non-cartilagoneous).

The adult body has about 206 bones

Conclusion - How the skeletal system links with the muscular system

The skeletal and muscular systems work together to help us move, give structure and provide protection for our organs. Tendons attach the muslce to the bone and ligaments attach the bones to one another.