BIOL302 Lecture Notes - Dense Irregular Connective Tissue, Bone Marrow, Osteoid

• School: University of Waterloo
• Department: Biology
• Course: BIOL302
• Professor: Mungo Marsden

Document Summary

Osteoblasts: located outside the bone, inactive = squamous, active = cuboidal, synthesize osteoid (bone matrix) Osteocytes: located inside bone, surrounded by lacuae and canaliculi, mineralize bone. Osteoclasts: located on surface of bone, large, multinucleated, for bone reabsorption secrete enzymes and acid, blood vessels, endocytosis, depression is resorption bay called howship"s lacunae. Periosteum = around: exterior surface bone, outer fibrous layer = dense irregular connective tissue, blood vessels, nerves, inner cellular layer = looser connective tissue, active cuboidal cells. Endosteum = lining: interior surface bone, lines marrow cavity, simple squamous (inactive, simple cuboidal (active) Primary bone (woven: immature bone; before mineralization, lots of osteocytes, random array of collagen. Secondary bone (lamellar: mature bone; mineralized, collagen arranged into lamellae, less osteocytes, two types: compact and spongy. Osteons contain central blood vessels/nerves, osteocytes, canaliculi (perpendicular, running outwards from harvesian canal) Intramembranous: mesenchymal cells differentiate to become osteoblasts. Osteoblasts secrete matrices that will become the osteoid (harvesian system).