Important of skeletal system:
Provide physical support
Attachment for muscles
- function in locomotion
Protection for the bodies
- protect the limb of organism
√Skeletal system on the outside of the body.
√Chitin shell is secreted by the mantle.
√Thin sheet of epithelial tissue that extends from body wall.
1st layer: Cuticle
√Made up of very thin laminations of chitin
√Wings, hair, legs
√No cell, unable to grow
√2 parts: epicuticle & procuticle
3 layers of exoskeleton:
2nd layer: Epidermis
Made up of a layer of living cell that secrete chitin making up the outer cuticle.
3rd layer: Basal membrane
Separate epidermis from internal body fluids and organs.
Cockroach molt exoskeleton
√Undergo the growth process
√Exoskeleton will split down the back and force it to climb out from the old cuticle.
√Takes six or seven molts for a newly hatched cockroach to reach sexual maturity.
Molt of exoskeleton:
Attachment of muscles on exoskeleton:
√Join of muscle to part of exoskeleton
√Allow muscle contraction
Example: flexor and extensor muscle
The two main muscles:
√Extensor tibiae muscle which causes the leg to extend
√Flexor tibiae muscle which causes the leg to flex.
√These tendons can be seen by removing the cuticle from one side of the leg in the joint region.