Bone Formation and Joints A560 – Fall 2015
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Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells Bone Formation and Joints a. Osteoblasts b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification C. Joints 1. Synovial 2. Intervertebral IV. Summary Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction Bone Formation and Joints II. Learning Objectives III. Slides and Micrographs 1. Bone is a specialized type of connective tissue with A. Bone (cont.) a calcified (mineralized) extracellular matrix (ECM); 1. General structure it serves to support the body, protect internal 2. Cells organs, and acts as the body’s calcium reservoir. a. Osteoblasts 2. Major cells of bone include: osteoblasts (form b. Osteoclasts osteoid which allows matrix mineralization to B. Bone Formation occur), osteocytes (from osteoblasts; enclosed in 1. Intramembranous ossification lacunae and maintain the matrix), and osteoclasts 2. Endochondral ossification (locally erode bone matrix during bone formation C. Joints and remodeling). 1. Synovial 3. Bone growth occurs via two basic mechanisms: 2. Intervertebral intramembranous ossification (bone forms within IV. Summary mesenchymal membrane) and endochondral ossification (bone replaces hyaline cartilage) 4. Joints are places where bones meet (articulate), allowing at least the potential of bending or movement; examples include, synovial joints (diarthrosis) and intervertebral joints Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction Learning Objectives II. Learning Objectives III. Slides and Micrographs 1. Understand the differences and similarities between intramembranous and A. Bone (cont.) 1. General structure endochondral bone formation and the key function of the periosteum in 2. Cells bone growth. a. Osteoblasts b. Osteoclasts 2. Understand the organization of the epiphyseal growth plate and its role in B. Bone Formation endochondral bone formation and growth of long bones. 1. Intramembranous ossification 2. Endochondral ossification C. Joints 3. Understand the structure of a typical synovial joint, including the nature 1. Synovial and functions of the synovium. 2. Intervertebral IV. Summary Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction Slide 129: Tooth, H&E II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells 104: Bone, H&E a. Osteoblasts Bone b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification C. Joints 1. Synovial 2. Intervertebral IV. Summary Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction Slide 129: Tooth, H&E II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts perforating B. Bone Formation 1. Intramembranous ossification (Volkmann’s) canals 2. Endochondral ossification osteon C. Joints 1. Synovial 2. Intervertebral IV. Summary central canal osteocyte in lacuna Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 104: Bone, H&E I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts B. Bone Formation resorption 1. Intramembranous ossification canals 2. Endochondral ossification C. Joints osteon 1. Synovial 2. Intervertebral central IV. Summary canal Osteon formation: resorption canals (with dimension of new osteon) are carved out of bone by osteoclasts; blood vessels and connective tissue invade and occupy the tunnel; osteoblasts begin to deposit new bone along the walls, forming lamellae; synthesis continuesfromperipheryto center until only central canal with neurovascular bundle remains in center Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 34: Healing Bone Fracture, H&E I. Introduction II. Learning Objectives Callus III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts B. Bone Formation 1 Cortical 1. Intramembranous ossification bone 2. Endochondral ossification C. Joints 1. Synovial Fracture 2. Intervertebral IV. Summary EC Hyaline 2 Oss Cartilage Sections (1) and (2) are two rib segments from a fetal/newborn rabbit; (1) gives an example of a bone fracture and repair processes (the callus is a temporary formation of highly proliferative fibroblasts and chondroblasts extending from the periosteum down into the fracture to formnewbone);(2) gives an example of endochondral ossification (EC Oss)bonegrowth Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 34: Healing Bone Fracture, H&E I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells CT a. Osteoblasts P b. Osteoclasts B. Bone Formation Act P 1. Intramembranous ossification 2. Endochondral ossification C. Joints M HC 1. Synovial 2. Intervertebral Wb IV. Summary Tb From the outside: (CT) is connective tissue proper surrounding the bone, note the abundant vasculature present; (P) is periosteum with clearly visible collagen bundles and (Act P) is an area of more active periosteum with lots of cellular differentiation occurring; (M) is marrow with abundant blood cells; (HC) are areas of hyaline cartilage; (Wb) is woven or primary bone being deposited upon hyaline cartilage (basophilic); there is an irregular arrangement of collagen fibers (acidophilic), large cell number, and reduced mineral content; (Tb) is mature (mineralized), trabecular bone; close examination shows endosteum on the edge of the bone bordering the marrow Lab 7 –Bone Formation and Joints Slide 34: Healing Bone Fracture, H&E A560 – Fall 2015 I. Introduction CT P II. Learning Objectives Cb III. Slides and Micrographs A. Bone (cont.) 1. General structure M 2. Cells a. Osteoblasts Tb b. Osteoclasts B. Bone Formation 1. Intramembranous ossification Wb 2. Endochondral ossification C. Joints 1. Synovial P 2. Intervertebral IV. Summary CT From the outside (top): (CT) is connective tissue proper surrounding the bone; (P) is periosteum with clearly visible collagen bundles; (Cb) is cortical bone with lamellar arrangement, note the adjacent central canal with surrounding rings of cartilage; (M) is marrow with abundant blood cells; (Tb) is trabecular bone, distinguished from cortical bone by the lack of osteons; close examination shows endosteum on the edge of the bone bordering the marrow; (Wb) iswovenorprimarybonewithanirregulararrangementof collagen fibers, large cell number, and reduced mineral content; osteoid (unmineralized bone) is the pale, acellular layer just below osteoblasts which line the edges of the nearby marrow cavities Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 34: Healing Bone Fracture, H&E I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts marrow b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification C. Joints 1. Synovial 2. Intervertebral endosteum IV. Summary lining trabecula Endosteum lines all internal surfaces of bone (both cortical and trabecular); it is generally only a single cell‐layer thick, and consists of inactive and active osteoblasts Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction Slide 34: Healing Bone Fracture, H&E II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification endosteum C. Joints 1. Synovial osteoid 2. Intervertebral IV. Summary lighter stained area between endosteum and mature bone mature bone Osteoid is collagen‐rich, non‐mineralized precursor to true bone matrix; it is secreted by osteoblasts during bone growth, repair, and remodeling; osteoblast subsequently calcify the osteoid into bony hard bony matrix; in the process, they become trapped in the matrix (in lacunae) and become osteocytes Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 34: Healing Bone Fracture, H&E I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification C. Joints inactive 1. Synovial periosteum: 2. Intervertebral w/ flattened IV. Summary osteoprogenitor cells maturing bone with osteocytes Lab 7 –Bone Formation and Joints A560 – Fall 2015 Slide 34: Healing Bone Fracture, H&E I. Introduction II. Learning Objectives III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts active B. Bone Formation periosteum: 1. Intramembranous ossification w/ rounded 2. Endochondral ossification or cuboidal C. Joints osteoblasts 1. Synovial 2. Intervertebral IV. Summary osteocyte Osteoblasts develop from osteoprogenitor cells (from mesenchymal cells) and are found lining the external and internal bone surfaces; they make osteoid (collagen‐rich matrix) which they then calcify into true hard, bony matrix; they become trapped in the matrix and become osteocytes Lab 7 –Bone Formation and Joints A560 – Fall 2015 I. Introduction II. Learning Objectives Slide 130: Membranous Bone, Fetal Skull III. Slides and Micrographs A. Bone (cont.) 1. General structure 2. Cells a. Osteoblasts b. Osteoclasts B. Bone Formation 1. Intramembranous ossification 2. Endochondral ossification C. Joints 1. Synovial 2. Intervertebral osteoblasts IV. Summary periosteum