1 Exam 2 review skeletal joints nervous systems Function of bones Support for body and soft organs o Bones of legs pelvic girdle vertebral and vertebral column support Protection for brain vital organs ribs and sternum protect lungs heart weight of erect body vertebrae protect spinal cord Movement as skeletal muscles use the bones as levers to move body Storage of minerals calcium and phosphorous and growth factors 99 of the body s calcium is stored in bones 85 of body s phosphorous store in bone Adipose tissue is found in yellow marrow of certain bones Blood cell formation hematopoiesis in red marrow cavities all blood cells are made in the marrow of certain bones Skeletal Cartilages Hyaline o Provide support flexibility resilience o Most abundant o Similar to hyaline but contain elastic fibers Elastic Fibrocartilage o Collagen fibers have great tensile strength Contain very few to no blood vessels or nerves Dense connective tissue girdle of perichondrium contains bloods vessels for nutrient delivery to cartilage Bones of the Skeleton 206 named bones in human body 2 large groups o axial forms long axis of body Includes the bones of the skull vertebral column and rib cage these bones are involved in protection support and carrying other body parts bones of upper and lower limbs and the girdles shoulder bones and hip bones that attach them to the axial skeleton Involved in locomotion and manipulation of the environment o appendicular Skull 2 sets of bones o cranial enclose brain in cranial cavity provide sites of attachment for head and neck muscles Paranasal Sinuses Vertebral Column functions curvatures o 2 o framework for face facial cavities for special sense organs openings for air food site of attachment for teeth and muscles of facial expression mucosa lined air filled spaces warm and moisten air lighten skull enhance resonance of voice found in frontal sphenoid ethmoid and maxillary bones o transmits weight of trunk to lower limbs surrounds and protects spinal cord flexible curved structure containing 26 irregular bones cervical 7 thoracic 12 lumbar 5 increase resilience and flexibility of spine two posteriorly concave curvatures cervical and lumbar two posteriorly convex curvatures thoracic and sacral o abnormal spine curvatures scoliosis abnormal lateral curve kyphosis hunchback lordosis swayback Intervertebral Discs cushion like pad composed of two parts o nucleus pulposus inner gelatinous nucleus that gives disc its elasticity and compressibility o annulus fibrosus outer collar composed of collagen and fibrocartilage Comparison of Female and Male Pelves female o adapted for childbearing true pelvis inferior to pelvic brim defines birth canal cavity of the true pelvis is broad shallow and has greater capacity o tilted less forward adapted for support of male s heavier build and stronger muscles cavity of true pelvis is narrow and deep male Compact Bone dense bone that contain many cylinder shaped units called osteon collagenous protein fibers and mineral deposits of calcium phosphate salts are found here within each osteon is a central Haversian canal that nerves and blood vessels use for passage o surrounded by concentric layers of calcified bone matrix 3 o haversian canals allow passage of blood vessels lymphatic vessels o each of the concentric matrix tubes that surrounds a Haversian and nerve fibers canal is known as lamella o all the collagen fibers in a particular lamella run in a single direction while collagen fibers in adjacent lamellae will run in opposite direction Allows bones to better withstand twisting forces o perforating Volkmann s canals at right angles to central canal connect blood vessels and nerves of periosteum and central canal lacunae are small cavities that contain osteocytes o o canaliculi are hair like canals that connect lacunae to each other and the central canal osteons are oriented longitudinally in long bones along lines of force o lamellae are weight bearing column like matrix tubes o central Haversian canal contains blood vessels and nerves Spongy Bone trabeculae or cancellous bone red bone marrow produces red blood cells in adults red bone formation occurs in spongy bone of skull ribs sternum vertebrae and in ends of long bones osetocytes are located in trabeculae and gets nutrients via diffusion trabeculae align along lines of stress no osteons contain irregularly arranged lamellae osteocytes and canciculi capillaries in endosteum supply nutrients Bones by Shape long bones longer than they are wide short bones cube shaped bones in wrist and ankle Sesamoid bones within tendons e g patella flat bones thin flat slightly curved scapulae sternum shoulder blades ribs irregular complicated shapes vertebrae hip bones sphenoid ethmoid bones wormian bones are small bone pieces that occur within a suture in the cranium not included in 206 bones Structure of a Long Bone epiphysis o thin layer of compact bone covering an interior of spongy bone at the end of the long bone o epiphyseal line disc is the remnant of the growth plate o articular hyaline cartilage on joint surfaces cushions the bone ends and reduces friction during movement diaphysis o the shaft of a long bone between the epiphyses o compact bone collar surrounds medullary marrow o medullary cavity in adults contains fat yellow marrow metaphysis 4 o region of mature bones where the diaphysis meets the epiphysis o epiphyseal plate in a growing bone the epiphyseal plate is formed of hyaline cartilage divided into 4 zones of cells under the influence of GH the plate continues to grow giving length to the bone when bone growth exceeds cartilage growth beginning at puberty the epiphyseal plate is slowly lost growth of long bones stops when the cartilage is completely o cavity of the shaft contains yellow marrow mostly fat in adults and contains red marrow for blood cell formation in infants medullary cavity gone Membranes of Bone Periosteum o Divided into an outer fibrous layer and an inner osteogenic layer Outer fibrous layer periosteum is composed of dense irregular CT containing blood vessels lymphatics and nerves that pass into the bone Inner osteogenic layer contains osteoblasts bone forming cells osteoclasts bone destroying cells osteogenic cells stem cells elastic fibers and various bone cell types particularly osteoprogenitor cells that give rise to new osteoblasts when stimulated o Functions in bone growth repair nutrition provides attachment points for skeletal muscles o Blunt
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