Unit 3 Lecture 1 Notes: Intro to Skeletal System
Unit 3 Lecture 1 Notes: Intro to Skeletal System 1223
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This 4 page Class Notes was uploaded by Anna Macione on Wednesday February 10, 2016. The Class Notes belongs to 1223 at Temple University taught by Dr. Rooney in Summer 2015. Since its upload, it has received 12 views. For similar materials see Anatomy & Physiology 1 in Kinesiology at Temple University.
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Date Created: 02/10/16
Human Anatomy and Physiology 1223 Spring 2016 Dr. Rooney Unit 3 Notes I. Body Systems Skeletal system supports the body Muscular system helps w/ movement II. Skeletal System Main parts include bones, cartilage, joints, ligaments Total 206 bones shared b/w axial and appendicular skeleton Axial skeleton: more centralized portion of the skeleton; includes skull, vertebral column, sternum, and rib cage (80 bones total) Appendicular skeleton: all appendages; includes upper/ lower extremities, and pectoral/ pelvic girdle (64 superior bones, 62 inferior bones) Primarily made of connective tissues, mostly bone and cartilage A. Functions of Skeletal System 1. Support: bones provide a basic structure, while soft tissue helps to glue the pieces together 2. Protection: vital organs held within the axial & appendicular skeleton (skull holds the brain) 3. Movement: lever system created by bones and joints, joint design helps with range of motion / possible movements 4. Production of RBC’s: main production occurs within the marrow 5. Storage: internal bone cavities keep fat inside to use for energy when needed; mainly minerals stores as mineral salts (Ca, P) and released when needed into the blood B. Classification of Bones 1. Long bones: enlarged head at each end, longer than they are wide ; most weight-bearing bones; includes femur, humerus, tibia, fibula 2. Short bones: usually more round in shape, length & width are somewhat even; shock absorbing bones; includes carpals/ tarsals 3. Flat bones: mostly flat surface w/ large surface for muscle attachment; protect vital organs; includes ribs, skull bones, sternum 4. Irregular bones: no real shape, functions are particular to the bone (vertebrae are used for PROTECTION of SPINAL CORD); includes facial bones, inner ear, vertebrae 5. Sesamoid bones: 2 ndtype of short bone, enclosed within tendon/ tissue; function serves to improve movement of muscular system; includes the patella in the kneecap C. Chemical Composition of Bones & Osseous Tissue Mainly composed of OSTEOIDS (organic material) Cells in bones include osteoblasts (form bone); osteoclasts; osteocytes (mature bone cells) - Osteogenic “bone forming” cells located in endosteum, periosteum & central canals create osteoblasts (again, the immature bone cells) - Fibroblasts multiply nonstop to give rise to osteoblasts - Mineralization of organic material in matrix of bone - Osteocytes (mature bone) are formed within the lacunae of the matrix when immature bone cells become trapped Osteoclasts: large specialized cells within inner bone; destroy and reabsorb bone by discharging metabolic acids/ lysosomal enzymes; then phagocytizes “eats” bone - Grow in bone marrow from stem cells; smalls burrows created within the bone are their residual spots D. Bone Matrix Hard bone matrix= hard bone Also made of organic substances; malleable strength due to mostly collagen fibers; helps to resist pulling/ tearing/ bending Inorganic substances (Ca, P) protect from compressing forces; pressure Combo of inorganic/ organic substances gives strength to bones More strength w/ compression force then tension force (fractures happen more often w/ tensile force) E. Microscopic Structure Bone matrix - lamellae (sheets) - lacunae (open spaces within lamellae) - osteocytes in lacunae - Canaliculi (thin processes thru the lamellae) - Gap junctions join processes (nutrients DIFFUSE thru to get to all osteocytes) F. Types of Bone Same material, arrange differently Cancellous= material > space * Cortical= material < space * 1. Cancellous “spongy” bone - Found in bones that experience ‘shock’ (mostly short/flat/irreg./ heads of long bones) - Trabeculae: Lamellae arranged in plates (spicules) of hard bone material o Many openings w/ bone marrow forming net-like appearance o Arranged in patterns that determine type of stress applied to bone; can rearrange! o Highly vascular - Lacunae in trabeculae plates - Osteocytes in lacunae 2. Cortical “hard” bone - Aka compact bone - Main function = support where tension/ compression forces are applied - Location in shaft of long bones/ covering spongy bone - Composition: Haversian ‘central’ canals, runs parallel to bone shaft o Transport for materials o Blood vessels for bone supply; nerves/ other connective tissue (CT) o Lamellae arranged in rings around Haversian Canal (solid, cylindrical tissue) o Osteocytes within lacunae, in lamellae arranged in rings o Canaliculi extending from lacunae (channels for connecting osteocytes) - Volkmann’s Canals: ‘perforating’ o connection b/w Haversian & external vessels @ right angle o Allows blood vessels in/out of Haversian G. Primary LONG Bone Structures 1. Diaphysis - long & narrow shaft; gets thicker towards ends from center - Medullary ‘marrow ‘cavity o Center of diaphysis, lines endosteum (composed of areolar CT w/ osteoblasts/ clasts) o Outer thin layer of spongy bone; RED bone marrow makes RBC’s in kids; YELLOW bone marrow replaces red in adult bones w/ fat deposits 2. Epiphyses - Rounded expansions @ ends of diaphysis - Spongy bone covered by layer of compact bone 3. Articular Cartilage: covers ‘articulating’ surfaces of long bones ( heads); hyaline is main type; reduce friction 4. Periosteum: 2 layer membrane on outer surface (NOT ARTICULAR CART.) - Inner layer= osteoblasts - Outer layer= dense fibrous CT 5. Outer Layer of Periosteum - Fibers of Sharpey: perforating, collagenous fibers, secure peri. to bone & ligaments/ tendons; VERY SECURE - Internal side: goes thru bone - External side: intertwine w/ tendinous fibers 6. Hollow Cylinder - Stronger than solid bone, lightweight - Critical for strong forces during movement H. Primary SHORT/ FLAT/ IRREG./ Bone Structures - similar structure to epiphysis of long bones - inner spongy bone (aka DIPOLE); covered by thin cortical bone - shock absorption o Flat bones: RED bone marrow = RBC’s I. RBC Production - Long bones: yellow bone marrow replaces red (age 18-22) - RBC manufactured by flat bones/ vertebrae J. Ossification: production of hardened bone from fibrous CT & cartilage
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