PTH_AS 2201 1st EditionExam # 2 Study GuideSkeletal System: Skeletal Tissues1. What is the Skeletal System good for? Support Protection Movement Blood Production Mineral and Electrolyte reservoirBONE CARTILAGE Stronger, stiffer, mineral reservoir, muscle attachment, & protection Flexible and shock absorbing  Articular cartilage, costal cartilage, Tracheal rings, Larynx, Intervertebral disks, External ear, NoseTypes: Compact(cortical) and Trabecular(Spongy)Types: Hyaline, Elastic, and Fibrocartilage2. Types of Cartilage:Hyaline Elastic Fibrocartilage Chondrocytes in lacunae in collagen matrix Similar to Hyaline; but has elastic fibers Rows of thick collagen fibers Most abundant… resilient to compression Tolerates bending  Resists tension & compression Where? -synovial joints  Where? –epiglottis, external ear Where? –Annulus fibrosus of intervertebral disk, knee meniscus, labrum of shoulder3. Types of Bone:Compact Trabecular Dense, outside of bones  Inside bones and surrounded by marrow Strong, rigid  Better at shock absorption Adjacent to joints4. Parts of Bone:Diaphysis- shaft of the bone (long middle part)Epiphysis- rounded end of the boneTrabeculae- inside the epiphysis; gives the spongy look; looks holeyMedullary cavity- inside the middle of the bone (the central cavity)Periosteum- outermost membrane that covers the bone; attached to compact bone by Sharpey’s Fibers; highly vascularized (vessels) and innervated (nerves…pain)Endosteum- tissue that lines the medullary cavity5. What is diploe?Specialized trabecular regions in the cranial vault6. SEQUENCE OF GROWTH AND OSSIFICATION Condensation: early embryonic organization of cells Ossification: Cartilaginous elements undergo endochondral ossification & Mesenchymal elements undergo intramembranous ossification Growth and Modeling: immature & juvenile element takes on its adult form. **Works in conjunction with ossification. Remodeling: adult bone is recycled and redistributed based on behavior7. ENDOCHONDRAL OSSIFICATION Arteries induce ossification of cartilage precursor Chondrocytes proliferate, die & are replaced by osteoblasts that secrete osteoid and form bone8. INTRA-MEMBRANOUS OSSIFICATION Osteoblasts condense w/in mesenchyme, secrete osteoid, and form bone Bones of face and cranial vault are derived via intramembranous ossification9. Cartilage and Bone GrowthInterstitial (growth from w/in) Appositional (growth from outside)Chondrocytes in matrix divide and secrete new matrixPerichondrium-dense connective tissue surrounding cartilageMatrix produced by chondrocytes w/in the cartilageSecretes matrix activelyMatrix produced by chondrocytes outside the cartilage(in the perichondrium) or produced by osteocytes in the periosteom or endosteum- Cartilage growth ends w/ teen years.- No blood supply to chondrocytes, cartilage gets nutrients from diffusion thru matrix- Limits cartilage thickness & growth- Calcifies with aging* MAKE SURE TO LOOK UP PICTURES OF THE 2 DIFFERENT TYPES OF GROWTH10. What is Achondroplasia?- Premature closure of primary growth plates- Sphenooccipital synchondrosis; short cranial base & moon shaped profile- Autosomal dominant; most common form of dwarfism (1/26,000 live births)11. What is the difference between modeling and remodeling?- Modeling= Early growth adds length & some shape- Remodeling= the bone still needs to modify its shape and internal physique to achieve adult form and respond to normal behaviors… therefore remodeling12. When is the ENTIRE skeleton replaced via remodeling?During the 1st year… then about 10% replaced each year. - Most of us are on our 3rd skeleton * 13. LOOK UP A PICTURE IN NOTES OF REMODELING AND MATURING BONE *Diagram*LOOK UP A PICTURE OF A OSTEON AND ITS PARTS (CENTRAL CANAL, LAMELLAE, OSTEOCYTE)14. What does Bone remodeling do?- Allows growth, shaping, repair, and mineral turnover15. Fun Fact:Breaking long bones damage tissues throughout the element healing process somewhat replicates the modeling to remodeling transition16. Vocabulary to know:Osteoblasts- secrete bone matrixOsteoclasts- reabsorb boneOsteoporosis- results from imbalance in normal building and degradation cycleOsteoarthritis- articular cartilage is thin and doesn’t have a good blood supply so it heals poorlyAxial Skeleton Primary Function of the Axial SkeletonProtection—Brain, spinal cord, internal organsThe four elements:- 1. Skull- 2. Hyoid- 3. Vertebral column- 4. Thoracic cage (ribs & sternum)1. Skull- 24 bones- Protects brain, house sensory organs, respiration, mastication, & communication- Mandible, Cranium, Neurocranium, Facial Skeletono Neurocranium= Frontal, Occipital, Sphenoid, Ethmoid, Parietals(2), Temporals(2) Sphenoid= has numerous foramina for passage of cranial nerves and vessels from the brain to orbit and face Ethmoid= Cribriform plate, olfactory bulb, olfactory receptors, odorants Temporal bones= Squamous portion(flat) and Petrous portion(dense part w/ inner ear) and Mandibular fossa forms temporomandibular joint with mandibleo Facial Skelton 14 Bones of the Faceo Mandible-jaw sectiono Vomero Nasals(2)o Lacrimals(2)- close by eyeso Maxillae(2)o Zygomatics(2)- cheek boneo Inferior nasal conchae(2)o Palatine(2) 3 Ear Ossicleso Malleuso Incuso Stapes2. Hyoid “Free floating” bone in neck Functionso Site of muscle attachmentso Masticationo Vocalization3. Vertebral column 26 vertebrae(5 divisions): protects spinal cord, anchors pectoral and pelvic girdleso Cervical(7)o Thoracic(12)o Lumbar(5)o Sacral(5)o Coccyx(4) KNOW THE ANATOMY OF ONE VERTEBRAEo Spinous process, Transverse process, articular process, vertebral foreman, body Cervical Vertebrae (C1-C7)o C1= Atlas Articulates with occipital Atlanto-occipital joint permits “yes” movemento C2= Axis Atlanto-axial joint permits “no” movement Thoracic Vertebrae (T1-T12)o Possess ribs Lumbar Vertebrae (L1-L5)o Large vertebral bodies Weight dissipation- Sacrumo 5 fused vertebraeo Part of pelvis Coccyxo Tail bones CURVES OF THE SPINE*******o Lordosis= curves anteriorly; extra curvature in the lumbar regiono Kyphosis= curves posteriorly; extended thoracic hump; caused from aging, osteoporosiso Osteoporosis & Dowager’s Humpo Scoliosis4. Thoracic Cage Sternum & 24 Ribs w/ costal cartilages Functionso Protect internal organs and