BIOL 2312 Lecture Notes - Lecture 46: Epiphyseal Plate, Haversian Canal, Medullary Cavity
Document Summary
Found in soft-bodied invertebrates (earthworms, slugs, jellyfish, and squids) Fluid-filled central cavity, encompassed by 2 sets of muscles: circular muscles: repeated in segments; run the length of the body, longitudinal muscles: oppose action of circular muscles. Exoskeleton made of polysaccharide chitin (not living tissue). Resists bending acts as skeletal framework. To grow, periodically molts and sheds exoskeleton. Vulnerable until new exoskeleton forms (crabs and lobsters hide) Insects breathe through openings in body (tiny tubules). Small body is better, muscles can"t enlarge: endoskeleton: Rigid, internal skeleton framework, muscle attachment. Echinoderms (sea urchins, sand dollars) skeleton made of calcite (crystalline form of calcium carbonate). Fibrous dense connective tissues w/ more rigid special connective tissues, cartilage or bone. Cartilage strong and slightly flexible (pad the ends of bones where they come together at a joint) Bone stronger than cartilage, less flexible. Bone: high metabolic rate can remodel in response to injury/stress. Bones form within a layer of connective tissue. (ex.
