BSCI 207 Lecture Notes - Lecture 36: Spinal Disc Herniation, Hydrostatic Skeleton, Endoskeleton
5 Dec 2016
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Skeletons serve to transmit, absorb, and resist forces. Skeletons are dynamic: they can interact with muscles, they can be modified over time. Bones fuse during development from an infant to an adult. Osteoblasts form bones and osteoclasts destroy weakened bone. Hydrostatic skeleton: these are fluid filled, pressurized chambers. An earthworm is an example: very dynamic and are composed of circular and longitudinal muscles. Earthworms crawl by peristalsis: in humans: Discs in between vertebrae (intervertebral discs) are comprised of a stiff material outside and a jelly-like substance inside. A herniated disc occurs when the disc pops open. Exoskeleton: comprise the majority of invertebrates and are typically made of chitin, like an endoskeleton, they can be pulled on by muscles. Exoskeleton: in vertebrates, can be comprised of both bones and cartilage, movements are made by the contraction of opposing muscle pairs. Muscles are connected to the bones thorough tendons. Skeletons are made up of a variety of materials; they are not homogenous.
