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Skeletal System Osteology: osteocyte periosteum Bone: connective tissue with a solid matrix each bone is an organ FUNCTIONS 1. support: rigid framework 2. protection: CNS, thoracic organs, red bone marrow, pelvic organs 3. body movement: levers 4. hemopoiesis: 5. storage of minerals: calcium and phosphorous 6. storage of lipids: yellow bone marrow Bone is a living, dynamic, adaptable tissue. It works with the muscular system for attachment, movement and a source of calcium and with the cardiovascular system as a site for blood cell production. SHAPE OF BONES 1. long bones 2. short bones: carpals and tarsals. Transfer forces of movement. 3. flat bones: broad surface for muscle attachment or protection of organs 4. irregular bones: ex. Vertebrae STRUCTURE OF A LONG BONE: fig. 6.5, p. 134 1. Diaphysis: contains a central cavity: medullary cavity the medullary cavity contains lipids: “yellow bone marrow” the medullary cavity is lined on the inside by endosteum ( c.t.) 2. Epiphysis: proximal and distal epiphysis contains “spongy” bone: “cancellous” bone “red bone marrow” 3. Epiphyseal plate/line: for lengthwise growth (fig. 6.11 p. 139) 4. Periosteum: (c.t.) two layers: outer fibrous, inner cellular covers and isolates important in bone growth and repair route for circulatory and nerve supply interwoven with tendons and ligaments continuous with the joint capsule Bone: osseous C.T. solid matrix vascular metabolically active: Osteon (functional unit) Two types: classified according to density or porosity A) Compact bone: dense, forms walls 1) Osteon: functional unit (Fig. 6.7 p. 136) aka. “Haversian system” Central canal Lamellae Lacuna Canaliculi Perforating canals 2) Cells: osteogenic osteoblast—osteogenesis osteoclast—osteolysis osteocyte B. Cancellous: spongy bone Contains same components, but arranged differently. Trabeculae: struts. Decreases weight and protects from stress in different directions. Surrounds yellow bone marrow. Is in epiphysis---red bone marrow. Periosteum covers long bones except at the articulating end of the proximal and distal epiphysis. This is articular cartilage: “hyalin” cartilage. It acts like teflon for joints. Bone growth and remodeling. Chondrocytes Ossification Skeletal system Two main divisions: I. AXIAL skeleton: (ch. 6) axis–lengthwise central line or part around which parts of a body are symmetrically arranged. Bones of the axial skeleton support and protect the organs of the head , neck and trunk. A. Skull B. Auditory ossicles C. Hyoid bone D. Vertebral column E. Rib cage ***Learn terms of table 6.2 p. 133 Lab starts with the vertebral column (p. 153) Functions: 1. Support & protect spinal cord vertebral foramen----vert. canal (part of dorsal cavity) 2. Opening for spinal nerves (intervertebral foramen) 3. Support head 4. Attachment of muscles, ribs and organs 5. Help maintain balance and position 6. Permit movement of head and trunk Regions 1. Cervical 2. Thoracic 3. Lumbar 4. Sacral and curves: kyphosis lordosis General structure of a vertebrae: Body Vertebral arch: pedicle & lamina Vertebral foramen 7 processes come off the vertebral arch (1) spinous process (2) transverse processes (2) superior articular processes (2) inferior articular processes scoliosis ARTICULAIONS Arthron: arthritis, arthroscopic surgery I. Functional classification of joints: based on degree of movement. A) Synarthroses B) Amphiarthroses C) Diarthroses II. Structural classification of joints: based on structure of joint. A) Fibrous B) Cartilaginous C) Synovial Functional class Structural class a) fibrous Synarthroses b) cartilaginous “synchondrosis” Example suture gomphosis epipyseal plate c) bony fusion “synostosis” Amphiarthroses Diarthroses a) fibrous “syndesmosis” between bones of antebrachium and leg (crural) b) cartilaginous “symphysis” fibrocartilage pad Intervertebral disc Symphysis pubis Synovial joint capsule with synovial fluid Structure of a Synovial Joint 1. Joint capsule: fibroelastic tissue, continuous with the periosteum a) synovial membrane: lines inside of the capsule secretes synovial fluid 2. Synovial fluid: lubricates nourishes the chondrocytes acts as shock absorber contains WBC 3. Articular cartilage: “hyaline” cartilage avascular teflon 4 Menisci (knee) fibrocartilage pad: cushions guides (TMJ–has “articular disc”) 5. Ligaments: dense fibrous C.T. connect bone to bone. can be inside joint capsule as well as outside 6. Bursae: flattened sacs that contain synovial fluid located where tendon passes over a bone or between muscles 7. Tendon sheath: similar to bursa but surrounds tendons(carpus and tarsus) 8. Tendons: dense fibrous c.t. that connects muscle to bone (periosteum) Range of motion determined by: 1. Bone structure (olecranon process and fossa) 2. Strength of joint capsule, ligaments and tendons 3. Muscles that span the joint Structural classification of Synovial Joints 1. Gliding – side to side; nearly flat; back & forth (little rotation) Ex. Wrist – carpls; Ankle – tarsals Sternoclavicular jt.; sup – inf art. P. 2. Hinge – Monaxial - movement One plane: knee, elbow, phalanges 3. Pivot – Rotation: C1/C2 – Prox radius/ulna 4. Condyloid – Convex – Concave – biaxial Radius - carples 5. Saddle – Convex – Concave; metacarples (thumb) - carples 6. Ball and Socket - multiaxial Read: Tibiofemoral joint (knee) p. 215-216 SKULL Sutures: coronal, sagittal, lambdoidal, squamosal, median palatine (fontanels: ossify by 24 months) I. CRANIAL BONES: A) FRONTAL (1): supraorbital margin, supraorbital foramen, frontal sinuses B) PARIETAL (2): C) TEMPORAL (2): 1) squamous part: zygomatic process, mandibular fossa 2) tympanic part: external acoustic meatus, styloid process 3) mastoid process: stylomastoid foramen 4) pterous part: carotid canal D) OCCIPITAL (1): foramen magnum, occipital condyles, hypoglossal canal, external occipital protuberance, superior nuchal line E) SPHENOID (1): body–sella turica & sphenoid sinus lesser wing, greater wing, medial & lateral pterygoid process, optic canal, superior orbital fissure, foramen ovale foramen rotundum, foramen lacerum, foramen spinosum F) ETHMOID (1): crista galli, cribriform plate & foramina, superior and middle nasal concha, perpendicular plate, ethmoid sinus II. FACIAL bones: A) MAXILLA (2): dental alveoli, palatine process, infraorbital foramen, inferior orbital fissure, maxillary sinus, median palatine suture B) PALATINE (2): horizontal plates, perpendicular plate, orbital surface C) ZYGOMATIC (2): temporal process (part of zygomatic arch) D) LACRIMAL (2): nasolacrimal canal E) NASA; (2): F) VOMER (1): G) MANDIBLE (1): body, ramus, condylar process, coronoid process, mandibular notch, mandibular foramen, pterygoid tuberosity, mylohyoid line III. Other bones A) Auditory ossicles: malleus, incus, stapes B) Hyoid: body, greater and lesser cornu SKULL A) Cranial bones: enclose and protect the brain B) Facial bones: do not come in contact with the brain, framework for face, support teeth, attachment for muscles that move jaw and for facial expression Inside the cranium, there are three fossas: 1) anterior cranial fossa: base of frontal bone (roof of orbit) to lesser wing of sphenoid, area for frontal lobes of cerebral hemisphere 2) middle cranial fossa: lesser wing of sphenoid to petrous part of temporal bone area for temporal lobes of cerebral hemispheres 3) posterior cranial fossa: petrous part of temporal bone to occipital bone area for cerebellum, pons, medulla oblongata