MUSCULOSKELETAL NO.1

MUSCULOSKELETAL NO.1

1. FUNCTIONS

   • SUPPORT
   • PROTECTION
   • LOCOMOTION
   • STORAGE
   • HAEMOPOIESIS
     •   Haemopoiesis- The production of blood cells and platelets in the bone marrow   
   • HOMEOSTATISIS
     •  stores some fluid, regulation of calcium and RBC count   

2. SKELETON= 3 PARTS

   • AXIAL
     • articulated bones of the head, vertebral column and thorax
   • APPENDICULAR
     • articulated bones of the upper and lower limbs
   • SPLANCHNIC
     •  the part of the skeleton that is connected to sense organs and viscera AKA 'floating bones'   

3. BONE STRUCTURE

   • HARD CONNECTIVE TISSUE
   • SUPPORT
   • LOCOMOTION
   • IT CAN DIE
     • If injured or blood supply is cut off
   • NEEDS NUTRIENTS
   • FLEXIBILITY & STRENGTH
   • CAN REPAIR/REMODEL

4. BONE MATRIX

   • OSTEOCYTES
     • bone cells
   • ORGANIC MATRIX
     • Produced by osteoblasts, containing mineral salts:
     • CALCIUM & PHOSPHOROUS
       • -inorganic  Gives rigidity 
     • COLLAGEN FIBRES
       • -Organic Gives strength and resilience 

5. BONE TYPES

   • COMPACT BONE
     • OUTER SURFACE
     • GIVES STRENGTH
     • OUTER LAYER (CORTEX)
     • STRUCTURE
       • HAVERSIAN CANALS
         • Various canals in compact bone through which blood vessels, nerve fibers and lymphatics pass through.
       • LAMELLAE
         • Bony concentric layers surrounding the Haversian in bone.
       • LACUNAE
         • a small cavity within the bone matrix, containing an osteocyte, and from which slender canaliculi radiate andpenetrate the adjacent lamellae to anastomose with the canaliculi of neighboring lacunae, thus forming a system of cavities interconnected by minute canals. -House osteoblasts
       • CANALICULI
         • branching tubular passages radiating like wheel spokes from each bone lacuna to connect with thecanaliculi of adjacent lacunae, and with the Haversian canal.
   • CANCELLOUS BONE (SPONGY BONE)
     • NO HAVERSIAN CANALS
     • TRABECULAE
       • A network of interconnecting ‘bars’ of bone creating a meshwork (like honeycomb). -Provides rigidity with minimum weight. 
       • BONE MARROW
         • Lies between the trabeculae (the spaces between)
     • MEDULLARY CAVITY
       • Spaces in the cancellous bone, containing bone marrow

6. BONE MARROW

   • A HAEMOPOIETIC TISSUE
     • Produces blood cells.
   • FOUND IN MEDULLARY CAVITY
   • YOUNG ANIMALS- RED
   • OLD ANIMALS- YELLOW

7. BLOOD SUPPLY

   • Via a Nutrient Artery which enters through a Nutrient Foramen.   

8. PERIOSTEUM

   • A dense connective tissue that covers bones, except at the joints where it is covered in cartilage
   • VASCULAR OUTER LAYER
   • CELLULAR INNER
     •  -contains osteoblasts and fewer blood cells
   • PROVIDES ATTACHMENTS
     • - For muscles, tendons, and ligaments