1 / 47

SKELETAL SYSTEM

SKELETAL SYSTEM. SKELETAL SYSTEM FUNCTIONS. Support (Primary function) Movement (Passive) Protection of Vital Organs Mineral Storage Blood Cell Formation (Hematopoiesis or Hemopoiesis). OSSEOUS TISSUE. Cancellous (spongy) Bone Compact (dense) Bone Bone Cells

Gabriel
Download Presentation

SKELETAL SYSTEM

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. SKELETAL SYSTEM

  2. SKELETAL SYSTEM FUNCTIONS • Support (Primary function) • Movement (Passive) • Protection of Vital Organs • Mineral Storage • Blood Cell Formation (Hematopoiesis or Hemopoiesis)

  3. OSSEOUS TISSUE • Cancellous (spongy) Bone • Compact (dense) Bone • Bone Cells • Osteoblasts – Secrete to form bone • Osteocytes • Mature bone cells • “Trapped” osteoblasts • Osteoclasts – destroy bone • Enzymes digest protein • Acids dissolve minerals • Forms Marrow Cavity; Involved in Remodelling

  4. CANCELLOUS OR SPONGY BONE • Open spaces, light weight • Lattice arrangement • Made of microscopic trabeculae subunits • Location of bone marrow • Site of blood cell formation (red marrow) • Within epiphyses of long bones

  5. COMPACT OR DENSE BONE • Dense, Ivory-like • Forms the outside layer of bones • Forms Diaphyses of long bones • Made of microscopic osteon (Haversian system) subunits

  6. Appendicular skeleton Axial skeleton STRUCTURAL CLASSIFICATION: APPENDICULAR AND AXIAL

  7. STRUCTURAL CLASSIFICATION BASED ON BONE SHAPE

  8. Short Bones Long Bone Flat Bone Irregular Bone STRUCTURAL CLASSIFICATION BASED ON TYPE OF BONE

  9. Epiphysis Spongy bone Compact bone Medullary cavity Diaphysis Epiphyseal line ANATOMY OF A LONG BONE • Periosteum • Epiphysis • Diaphysis • Compact bone • Spongy bone • Medullary cavity • Endosteum • Nutrient foramen • Epiphyseal line

  10. BONE DEVELOPMENT • Ossification = replacement of other tissues with bone • Begins about the 6th week of gestation • Size increases until late teens (females) to mid-twenties (males) • Requires Ca2+ • Ossification processes include: • Intramembranous bone formation • Endochondral bone formation

  11. GENERAL FEATURES OF INTRA-MEMBRANOUS BONE FORMATION • Occurs in flat bones of skull, clavicles • Begins with collagenous fiber membrane model • Membrane calcifies into compact bone • Fontanels (“Soft spot”, not yet ossified)

  12. THE PROCESS OF INTRA-MEMBRANOUS BONE FORMATION • C.T. Cells cluster & centers of ossification appear • Cells differentiate into osteoblasts • Osteoblasts secrete a matrix, forming trabeculae • Calcium salts are deposited

  13. THE PROCESS OF INTRA-MEMBRANOUS BONE FORMATION CONTINUED • Trabeculaefuse into spongy bone lattice • Lattice fills with red bone marrow • Eventually, peripheral trabeculae thicken into compact bone (periosteal ossification)

  14. GENERAL FEATURES OF ENDOCHONDRAL BONE FORMATION • Occurs in remainder of skeleton • Begins with hyaline cartilage model • Cartilage is replaced by bony tissue

  15. THE PROCESS OF ENDOCHONDRAL BONE FORMATION • FORMATION OF BONE COLLAR • Cartilage model is covered by perichondrium • Perichondrium becomes periosteum • A “collar” of bone is produced around the diaphysis

  16. THE PROCESS OF ENDOCHONDRAL BONE FORMATION • CALCIFICATION OF DIAPHYSEAL CARTILAGE • Hypertrophy of chondrocytes • Surrounding matrix calcifies • Diffusion disabled, chondrocytes die • Cartilaginous matrix disintegrates

  17. THE PROCESS OF ENDOCHONDRAL BONE FORMATION CONTINUED • FORMATION OF PRIMARY OSSIFICATION CENTER • Diaphysis penetrated by blood vessels, osteoblasts, osteoclasts • Marrow cavity formed by osteoclasts • Trabeculae form (Spongy bone) • Cartilage model grows at ends, elongating bone

  18. THE PROCESS OF ENDOCHONDRAL BONE FORMATION CONTINUED • FORMATION OF SECONDARY CENTER OF OSSIFICATION • Blood vessels reach epiphyses • Secondary ossification centers develop • Spongy bone is formed • Cartilage is replaced by bone, except at articular surfaces • Cartilage remains at epiphyseal plate (metaphysis) until growth is complete

  19. FRACTURES AND THEIR REPAIR • Definition: Any break in a bone • Repair may take months • Types include • Simple (skin not broken) • Compound (bone protrudes through skin) • Greenstick (shaft bent/broken) • Spiral (twisting force, ragged break) • Comminuted (shattered into fragments)

  20. STEPS IN FRACTURE REPAIR • Broken blood vessels form a fracture hematoma • C.T. and Capillaries invade site, form fibrocartilage callus • Repair cells (osteoblasts) are activated in about 48 hours • Bony callus replaces fibrocartilage callus • Bony callus is remodeled by osteoclasts

  21. BONES AS LEVERS • Lever: A rigid rod that moves about a fixed point • Fulcrum: The fixed point around which a lever moves (joints) • Forces: Act to move levers at two points • Resistance: Force to be overcome • Effort or Work: Force required to overcome resistance; supplied by skeletal muscles

  22. CLASSES OF LEVERS • First Class: The fulcrum is between the effort/force and the resistance • Seesaw • Tilting head backward

  23. R R R R R R R F E E E E E E E FIRST CLASS LEVER

  24. CLASSES OF LEVERS CONTINUED • Second Class: Resistance is between the fulcrum and the effort/force • Wheelbarrow • Rising up on one’s toes

  25. R R R R R R R R F E E E E E E E E SECOND CLASS LEVER

  26. CLASSES OF LEVERS CONTINUED • Third Class: The effort/force is between the fulcrum and the resistance • Most common type in the human body • Flexing the elbow

  27. R R R R R R R R F E E E E E E E E THIRD CLASS LEVER

  28. ARTICULATIONS: CLASSIFICATION BY FUNCTION

  29. ARTICULATIONS: CLASSIFICATION BY STRUCTURE

  30. Pubic symphysis Functional: AmphiarthrosisStructural: Cartilagenous Knee Functional: DiarthrosisStructural: Synovial Sutures Functional: SynarthrosisStructural: Fibrous ARTICULATIONS: EXAMPLES

  31. STRUCTURE OF A SYNOVIAL JOINT • Articular cartilage – cover bone ends • Synovial membrane – lines joint capsule • Synovial fluid – lubricates & nourishes cartilage • Synovial cavity • Joint capsule – fibrous C.T. • Ligaments – reinforce joint • Bursae – synovial sacs at other sites of friction

  32. TYPES OF SYNOVIAL JOINTS Classified based on shape of articular surfaces • Gliding (plane) • Hinge • Pivot • Ellipsoidal (condyloid) • Saddle • Ball-and-socket

More Related