Weeks 5 and 6
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This 4 page Class Notes was uploaded by Kaydra Notetaker on Friday September 25, 2015. The Class Notes belongs to BIOL 237 at University of New Mexico taught by Shaner in Summer 2015. Since its upload, it has received 32 views. For similar materials see Human Anatomy and Physiology I for the Health Sciences in Biology at University of New Mexico.
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Date Created: 09/25/15
Weeks 5 and 6 The Skeletal System Skeletal Cartilages highy resilient not vascularized not innervated Types 1 Hyaline most abundant gives support flexibility and resilience found in the nose ears and joints 2 Elastic simiar in structure to Hyaline has more elastic fibers found in the outer ear and epiglottis 3 Fibrocartilage made of thick collagen fibers used for tensile strength found in the discs in the spinal column the meniscus and the pubic symphysis Growth of Cartilage Types 1 Appositional Growth growth from the outside of the cell growth starts at the outer edges of the cartilage and grows wider 2 Interstitial Growth growth from the inside of the cell grows ong Axial Skeleton consists of the skull and spine provides support and protection Appendicular Skeleton consists of long bones found on extremities provides movement General Classifications of Bones 1 Long Bones onger than they are wide exampes humerus fingers toes 2 Short Bones as wide are they are long cuboidaooking exampes wrists ankles 3 Flat Bones reverberate exampe sternum sku Weeks 5 and 6 4 Irregular Bones don t fall into any other category example vertebra Functions of Bones 1 2 3 4 TI 03 Suppon Protection Movement Muscles use bones as levers Mineral and Growth Factor Storage Calcium and Phosphates Blood Cell Formation hematopoiesis Triglyceride Storage body uses this as the last resort in surviving starvation Hormone Production Osteocalcin regulates bone formation protects against obesity and glucose intolerance diabetes Bone Structure 1 Gross Anatomy Types of Bone 1 Compact Bone hard outer covering of bones 2 Spongy Bones projections called trabeculae bone marrow found within Anatomy of a Long Bone 1 Diaphysis shaft 2 Epiphysis end Endosteum Covers the inner lining of the bone Connective tissue Periosteum Covers the outer lining of the cell Connective Tissue Epiphyseal Line growth plate it open if closed no further growth is possible Hematopoiec Tissue vascularized contains bone marrow made of stem cells and platelets types 1 Yellow high lipid content 2 Red after lipid supply has been depleted Weeks 5 and 6 more active in blood cell formation than yellow babies have primarily red bone marrow the two can change readily back and forth Bone Markings characteristics of bones that indicate what is around them within the body 2 Microscopic Anatomy Types of Bone Cells 1 Osteogenic Cell stem cells in the bones actively mitotic give signals to differentiate 2 Osteoblast actively mitotic bone forming synthesizes the bone matrix responsible for bone growth 3 Osteocyte mature cell bone remodeling sensitive to stress and strain send signals to the osteoblasts to synthesize bone matrix 4 Osteocyte boneresorbing cell breaks down bone think macrophage but in bone cell form 5 BoneLining Cell lines the bone surfaces inside and outside help to maintain protect the matrix Compact Bone Made up of Osteon the functional unit of the bone made up of 1 Central Canal includes arteries with capillaries veins and nerve endings 2 Lamellae made up of alternating collagen fibers and bone salts aows for resistance against twisting forces Perforating Canal aows blood vessels and nerve ending to penetrate the spongy bone Lacunae lakes openings in the osteon that contains osteocytes Canaliculi cracks canals that connect lacunae to each other and to the central canal opens ability for communication between cells forms when bone matrix hardens Spongy Bone made up of projections Weeks 5 and 6 trabeculae Bone Chemistry 1 Osteoid made up of protyoglacans glycoproteins and collagen fibers makes up 13 of the bone matrix collagen fibers form bonds sacrificial bonds break easily dissipates force on the bone makes it less likely to experience a break in the bone 2 Inorganic Material Hydroxyapatites calcium phosphates bound together gives bones hardness helps to resist concussion of bone tissue persists for a LONG time we re talking mummies from Egypt long capture isotopes and can help trace bones back to locations Bone Development Ossification Osteogenesis 1 Endochondral Ossification bones develops in place of the hyaline cartilage that makes up the fetal cartilage skeleton Stages 1 Osteoblasts secrete osteoids happens at about Week 9 the bone collar forms around the diaphysis of the cartilage 2 Cartilage is dying and becomes permeable to everything cartilage in the center of the diaphysis calcifies and develops cavities 3 Periosteal bud invades internal cavities and spongy bone forms Month 3 periosteal bud contains blood vessels nerve endings marrow elements osteogenic cells differentiate and cause osteoblasts to secrete osteoid around the remaining cartilage 4 Diaphysis elongates and medullary cavity forms secondary ossification centers appear in epiphyses leads to epiphyseal plate medullary cavity contains blood vessels nerve endings and eventually bone marrow 5 Epiphyses Ossify childhood to adolescence hyaline cartilage exists only in the epiphyseal plates