FUNCTIONS OF SKELETAL SYSTEM

-Support - framework for the attachment of soft tissue

-Protects soft tissues

-Storage depot - calcium salts that make bones hard is valuable 

   mineral reserve

-Blood cell production 

-Movement - form levers that skeletal muscles attach

MATRIX OF OSSEOUS TISSUE

-Salts (2/3) provide bone with compressional strength

-Calcium phosphate and calcium hydroxide combine to

     crystals (AKA harden bone)

-Other salts are also present in lesser amounts (sodium,

    magnesium, fluoride) Collagen (1/3) provide bone with  

    tensile strength(aka flexibility of cells)

CELLS OF OSSEOUS TISSUE OSTEOCYTES

-Mature bone cells

-Regulate and monitor protein and mineral content of the matrix -Occupy small chambers (lacunae) that are between layers of

   calcified matrix (lamellae)

-Channels (canaliculi) permeate the matrix from lacuna to lacuna

   and provide a route for diffusion of nutrients and waste

   products

CELLS OF OSSEOUS TISSUE OSTEOBLASTS

-responsible for production of new bone by secretion of

   osteoid which later becomes ossified

-make new bone

-when calcium salts are deposited, these become osteocytes

CELLS OF OSSEOUS TISSUE OSTEOPROGENITOR

-Stem cells that can produce more osteoblast

-Important during times of injury

CELLS OF OSSEOUS TISSUE OSTEOCLASTS

-Giant cell with 50 or more nuclei

-Secrete acids that dissolve bone matrix

Amino acids

Minerals

-Important regulation of the activity of osteoblasts and

 osteoclasts

-multinucleated

*osteoporosis - clasts work faster than blasts

BONE TISSUE

-2 TYPES,

-BOTH IS FOUND IN MOST BONES

1)COMPACT BONE

2)SPONGY BONE

COMPACT BONE

-dense and solid and generally forms the walls of typical bones -Provides tremendous vertical strength

 -Osteons or Haversian systems form the functional unit

OSTEONS/HAVERSIAN SYSTEMS OF COMPACT BONE

-Central (Haversian) canals - blood supply

-Perforating canals (canals of Volkman) extend perpendicularly

  and deliver blood into deep osteons and service the marrow

  cavity

-Concentric lamellae, canaliculi, lacunae

-Interstitial lamellae fill in spaces between osteons

-Circumferential lamellae cover the external and internal

  surface of compact bone

SPONGY BONE

-forms an open network of struts and plates and is arranged in an internal layer surrounding the marrow cavity 

-Maintains strength but makes the bone much lighter  

-Lamellae form trabeculae 

-Nutrients enter bone through canaliculi (no central canal as in

   osteons)

*NO OSTEONS *ON INNER LAYER B/T COMPACT BONE *CANALICULI=TINY HOLES ON TRABECULAE

PERIOSTEUM MEMBRANE OF BONE

-outer membrane(dense irreg. CT)

- Isolates and protects bone from surrounding tissue

-Location of attachment of blood vessels and nerves

-Involved in bone growth and repair

-Attachs bone to connective tissue network of the deep fascia

ENDOSTEUM MEMBRANE OF BONE

-Lines the marrow cavity (inner membrane)

-Lines the central canals of osteons

*simple squamous

LONG BONES

-humerous, radius, ulna, femur

-Diaphysis (shaft)

-Epiphyses (2) - growth plates

-Metaphyses (2) – connects

-Marrow cavity - blood production

SHORT BONES

-carpal bones and tarsal bones

-Box-like bones Compact and spongy bone (no marrow)

FLAT BONES

-roof of skull, sternum, ribs, scapulae

-Compact and spongy bone

-Usually curved bones(ribs, skull)

IRREGULAR BONES

SESAMOID

- patella

-within a tendon or crossing a joint

ex:in point finger and big toe and wrist

WORMIAN

PNEUMATIZED

-hollow or contain air pockets/sinuses

ex:frontal and sphenoid

bone markings

SINUS

bone markings

FISSURE

bone markings

FORAMEN

bone markings

FOSSA

bone markings

PROCESS

bone markings

RAMUS

bone markings

MEATUS

bone markings

SPINE

bone markings

CREST

bone markings

HEAD

bone markings

TROCHANTER

large, rounded projection

-muscle attachment

bone markings

TUBEROSITY

rough projection

-muscle attachment

bone markings

TUBERCLE

small, rounded projection

-muscle attachment

bone markings

FACET

small, flat, articulating surface

-bone articulation (2 bones connected)

bone markings

CONDYLE

smooth, rounded articular process

--bone articulation (2 bones connected)

bone markings

TROCHLEA

smooth, grooved articular process

-bone articulation (2 bones connected)