Muscular system
A cheetahs muscles are alot quicker to react to brain signals than to a humans, this enables them to reach their top flight speed in under 30 seconds. It has a very muscular lean body, it does not have alot of muscle but the muscle thats there is all fine tuned to do exactly what it's meant to. The cheetah's paws have semi-retractable claws (known only in three other cat species: the Fishing Cat, the Flat-headed Cat and the Iriomote Cat) offering extra grip in its high-speed chases. The ligament structure of the cheetah's claws is the same as those of other cats; it simply lacks the sheath of skin and fur present in other varieties, and therefore the claws are always visible, with the exception of the dewclaw. The dewclaw itself is much shorter and straighter than that of other cats. Large nostrils help them reach these speeds because they are then able to increase their oxygen intake. Also their enlarged heart and lungs help move the large amounts of oxygen through the body more efficiently. Their spine is flexible and acts like a spring when they run. Also, their tail is designed to help them with their speed. The tail helps maintain their balance as they run and helps with quick turns. They need to turn quickly when chasing their prey, like a gazelle. The gazelles turn rapidly to get away from their predator. However the cheetah’s tail helps them turn with the gazelle to help them keep up with the graceful and fast moving gazelle.http://www.bio.davidson.edu/people/midorcas/animalphysiology/websites/2011/Ptaschinski/Builtforspeed.htm