BSC 109 1nd Edition Lecture 8Outline of Last Lecture I. The skin as an organ system (continued)II. Skim disorders and diseasesOutline of Current Lecture I. Skeletal system consists of connective tissueA. Bone: hard elements of the skeleton1. Functions2. Contains living cells3. Ligaments hold bones together4. Cartilage lends support5. Bone development begins as embryo6. Bones undergo repair7. Skeletal systemCurrent LectureI. Skeletal system consists of consists of connective tissueA. Bone: hard elements of the skeleton1. Functions: support, protection, movement, blood cell formation, mineral storage (calcium and phosphate)2. Contain living cellsa) Inorganic matrix of calcium salts(1) Compact bone: shaft, ends, marrow of bone(2) Yellow bone marrow: fat marrow space(3) Spongy bone: lattice-like support, lighter (spaces contain red bone marrow)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.(4) Cells: osteoblasts, osteocytes, osteoclasts-“osteo” means bone-“blasts” make other cells-“cytes” are mature cells-“clasts” recycle dead cells(5) Types: long, flat, irregular(6) Osteons/haverson system: cellular arrangement(7) Periostium: connective tissue covering(8) Blood vessels run through center3. Ligaments hold bones togethera) Bone to boneb) Dense fibrous connective tissuec) Provides strength to joint, enables movement4. Cartilage lends support (3 types)a) Fibrocart: has a lot of fiber/strings; found in intervertebral disks; helps keep spine vertebrae from rubbing together; found in menisci of the knee and disks in the spine (“herniated disk” is the result of destroyedfibrocart)b) Hyaline: instruction for laying down bones (when babies); covers/protects ends of long bones and jointsc) Elastic: movable/flexible, lightweight (as in ears)5. Bone development begins as embryoa) Begins as a few cells which develop into hyaline, which is formed by chondroblasts (“chondro” means cartilage)b) Signal comes in at some point and instructs osteoblasts to lay down a calcium matrixc) Secondary ossification sites are formed at childhoodd) Preadolescence: human growth hormone stimulates bones to lengthene) Early adolescence: hormones (estrogen, testosterone) kick in, stimulating more bone lengtheningf) Late adolescence: testosterone and estrogen signal bones to close cartilage and bone gapsg) Remolding, replacing, maturing bone always as long as good diet/nutrition/consistent weight-bearing exercisesh) Osteoporosis: loss of bone mass due to prolonged imbalance of osteoblasts/clasts6. Bones undergo repaira) Bone fracture (upon impact)b) Hematoma formation (blood clot) at site of fracturec) Brings fibroblasts to begin repairing processd) Callous forms (made of cartilage)e) Osteoblasts lay down a new bone, new areas will heal much stronger than they were originally7. Skeletal systema) 206 bones (typically)b) 4 types: long, short, flat, irregularc) function: protection/support for organs, flexibility, minerals, bloodsynthesisd) cranium, maxilla, mandible, sternum, ribs, vertebrae, sacrum, phalanges, metatarsals, tarsals, fibula, tibia, patella, femur, coccyx bone, metacarpals, carpals, radius, ulna, humerus, scapula, claviclee) Axial (trunk)(1) Hyoid bone: in throat for talking, tongue, larynx(2) Skull: cranium(3) Vertebral column: protects spinal cord: cervical, thoracic, lumbar, sacrum, coccyx(4) Ribs protect heart, lungs(5) Sternum protects the heartf) Appendicular (appendages)(1) Pectoral girdle, limbs(2) Wide range of motion(3) Swollen tendons(4) Carpal tunnel syndrome: repetitively swollen nerves (very painful)(5) Pelvic girdle always wider in women to accommodate for childbirthg) Joints classified by movement(1) Fibrous: immovable(2) Cartilaginous: slightly movable(3) Synovial: freely movable (arms); fluid filled sack that lubricates and separates bones and keeps bones from rubbing together(a) Often has membrane and hyaline cartilage(b) Membrane secretes fluid(c) Cartilage acts as a cushion(d) Hinge or ball and socket(e) Tendons join bone to muscleh) Tendons and