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6      Bones  and  Skeletal  Tissues:  Part  A  

Skeletal  Car;lages  

•  Contain  no  _________________  or  _______________  

•  Dense  connec;ve  ;ssue  girdle  of  perichondrium  contains  blood  vessels  for  ___________________  delivery  to  car;lage  

Skeletal  Car;lages  

1.  _____________  car;lages  –  Provide  support,  flexibility,  and  resilience  –  Most  abundant  type  

2.  _____________  car;lages  –  Similar  to  hyaline  car;lages,  but  contain  elas;c  fibers  

3.  Fibrocar;lages  –  Collagen  fibers—have  great  tensile  strength  

Figure 6.1

Axial skeleton Appendicular skeleton

Hyaline cartilages Elastic cartilages Fibrocartilages

Cartilages

Bones of skeleton

Epiglottis Larynx

Trachea Cricoid cartilage Lung

Respiratory tube cartilages in neck and thorax

Thyroid cartilage Cartilage in

external ear Cartilages in nose

Articular Cartilage of a joint

Costal cartilage

Cartilage in Intervertebral disc

Pubic symphysis

Articular cartilage of a joint

Meniscus (padlike cartilage in knee joint)

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Growth  of  Car;lage  

•  Apposi;onal  –  Cells  secrete  matrix  against  the  external  face  of  exis;ng  car;lage  

•  Inters;;al  –  Chondrocytes  divide  and  secrete  new  matrix,  expanding  car;lage  from  within  

•  _____________  of  car;lage  occurs  during  –  Normal  bone  growth  –  Old  age  

Bones  of  the  Skeleton  

•  Two  main  groups,  by  loca;on  – _____________  skeleton  (brown)  – _____________  skeleton  (yellow)  

Figure 6.1

Cartilage in external ear

Cartilages in nose

Articular Cartilage of a joint

Costal cartilage

Cartilage in Intervertebral disc

Pubic symphysis

Articular cartilage of a joint

Meniscus (padlike cartilage in knee joint)

Classifica;on  of  Bones  by  Shape  

•  _____________  bones  – Longer  than  they  are  wide    

•  _____________  bones  – Cube-­‐shaped  bones  (in  wrist  and  ankle)  – Sesamoid  bones  (within  tendons,  e.g.,  patella)  

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Classifica;on  of  Bones  by  Shape  

•  _____________  bones  – Thin,  flat,  slightly  curved    

•  _____________  bones  – Complicated  shapes    

Figure 6.2

Func;ons  of  Bones  

•  _______________  – For  the  body  and  soZ  organs  

•  ______________  – For  brain,  spinal  cord,  and  vital  organs  

•  ______________  – Levers  for  muscle  ac;on  

Func;ons  of  Bones  

•  ______________  – Minerals  (calcium  and  phosphorus)  and  growth  factors  

•  ______________  forma;on  (hematopoiesis)  in  marrow  cavi;es    

•  Triglyceride  (______________)  storage  in  bone  cavi;es  

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Bone  ______________  

•  Bulges,  depressions,  and  holes  serve  as  – Sites  of  a[achment  for  muscles,  ligaments,  and  tendons  –  Joint  surfaces  – Conduits  for  blood  vessels  and  nerves  

Bone  Markings:  Projec;ons  

•  Sites  of  muscle  and  ligament  ______________  –  Tuberosity—rounded  projec;on  –  Crest—narrow,  prominent  ridge    –  Trochanter—large,  blunt,  irregular  surface  –  Line—narrow  ridge  of  bone  –  Tubercle—small  rounded  projec;on  –  Epicondyle—raised  area  above  a  condyle  –  Spine—sharp,  slender  projec;on  –  Process—any  bony  prominence  

Table 6.1

Bone  Markings:  Projec;ons  

•  Projec;ons  that  help  to  form  joints  –  ______________  

•  Bony  expansion  carried  on  a  narrow  neck  –  ______________  

•  Smooth,  nearly  flat  ar;cular  surface  –  ______________  

•  Rounded  ar;cular  projec;on  –  ______________  

•  Armlike  bar    

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Table 6.1

Bone  Markings:  Depressions  and  Openings  

•  Meatus  –  Canal-­‐like  passageway  

•  ______________  –  Cavity  within  a  bone  

•  Fossa  –  Shallow,  basinlike  depression  

•  Groove  –  Furrow  

•  Fissure  –  Narrow,  slitlike  opening  

•  ______________  –  Round  or  oval  opening  through  a  bone  

Table 6.1

Bone  Textures  

•  ______________  bone  – Dense  outer  layer  

•  Spongy  (______________)  bone  – Honeycomb  of  trabeculae    

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Structure  of  a  Long  Bone  

•  ______________  (shaZ)  – Compact  bone  collar  surrounds  medullary  (marrow)  cavity  

– Medullary  cavity  in  adults  contains  ______________  (yellow  marrow)  

Structure  of  a  Long  Bone  

•  ______________  – Expanded  ends    – Spongy  bone  interior    – Epiphyseal  line  (remnant  of  growth  plate)    – Ar;cular  (______________)  car;lage  on  joint  surfaces    

Figure 6.3a-b

Proximal epiphysis

(b)

(a)

Epiphyseal line

Articular cartilage

Periosteum

Spongy bone

Compact bone

Medullary cavity (lined

by endosteum)

Compact bone

Diaphysis

Distal epiphysis

Membranes  of  Bone  

•  ______________  –  Outer  fibrous  layer  –  Inner  osteogenic  layer  

•  Osteoblasts  (bone-­‐forming  cells)  •  Osteoclasts  (bone-­‐destroying  cells)  •  Osteogenic  cells  (stem  cells)  

–  Nerve  fibers,  nutrient  blood  vessels,  and  lympha;c  vessels  enter  the  bone  via  nutrient  foramina  

–  Secured  to  underlying  bone  by  Sharpey’s  fibers  

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Membranes  of  Bone  

•  ______________  – Delicate  membrane  on  internal  surfaces  of  bone  – Also  contains  osteoblasts  and  osteoclasts  

Figure 6.3c

(c)

Yellow bone marrow

Endosteum

Compact bone

Periosteum

Perforating (Sharpey’s) fibers

Nutrient arteries

Structure  of  Short,  Irregular,  and  Flat  Bones  

•  ______________-­‐covered  compact  bone  on  the  outside    

•  ______________-­‐covered  spongy  bone  within    •  Spongy  bone  called  diploë  in  flat  bones    •  Bone  marrow  between  the  trabeculae  

Figure 6.5

Compact bone

Trabeculae

Spongy bone (diploë)

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Loca;on  of  Hematopoie;c  Tissue  (_____  _________)  

•  Red  marrow  ______________  of  adults  – Trabecular  cavi;es  of  the  heads  of  the  femur  and  humerus  

– Trabecular  cavi;es  of  the  diploë  of  flat  bones  •  Red  marrow  of  newborn  infants  

– Medullary  cavi;es  and  all  spaces  in  spongy  bone    

Microscopic  Anatomy  of  Bone  

•  Cells  of  bones  – ______________  (osteoprogenitor)  cells  

•  Stem  cells  in  periosteum  and  endosteum  that  give  rise  to  osteoblasts  

– ______________  •  Bone-­‐forming  cells  

 

Figure 6.4a-b

(a) Osteogenic cell (b) Osteoblast

Stem cell Matrix-synthesizing cell responsible for bone growth

Microscopic  Anatomy  of  Bone  

•  Cells  of  bone  – ______________  

•  Mature  bone  cells  

– ______________  •  Cells  that  break  down  (resorb)  bone  matrix    

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Figure 6.4c-d

(c) Osteocyte

Mature bone cell that maintains the

bone matrix

(d) Osteoclast

Bone-resorbing cell

Microscopic  Anatomy  of  Bone:  Compact  Bone  

•  Haversian  system,  or  osteon—______________  – Lamellae  

• Weight-­‐bearing  •  Column-­‐like  matrix  tubes  

– Central  (Haversian)  canal  •  Contains  ______________  and  ______________  

Figure 6.6

Structures in the central canal

Artery with capillaries

Vein Nerve fiber

Lamellae

Collagen fibers run in different directions

Twisting force

Microscopic  Anatomy  of  Bone:  Compact  Bone  

•  Perfora;ng  (______________)  canals  – At  right  angles  to  the  central  canal  – Connects  blood  vessels  and  nerves  of  the  periosteum  and  central  canal  

•  ______________—small  cavi;es  that  contain  osteocytes  

•  ______________—hairlike  canals  that  connect  lacunae  to  each  other  and  the  central  canal  

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Figure 6.7a-c

Endosteum lining bony canals and covering trabeculae

Perforating (Volkmann’s) canal

Perforating (Sharpey’s) fibers

Periosteal blood vessel Periosteum

Lacuna (with osteocyte)

(a)

(b) (c)

Lacunae

Lamellae

Nerve Vein Artery

Canaliculi Osteocyte in a lacuna

Circumferential lamellae

Osteon (Haversian system)

Central (Haversian) canal

Central canal

Interstitial lamellae

Lamellae

Compact bone

Spongy bone Microscopic  Anatomy  of  Bone:  Spongy  Bone  

•  ______________  – Align  along  lines  of  stress  – No  osteons  – Contain  irregularly  arranged  lamellae,  osteocytes,  and  canaliculi  

– Capillaries  in  endosteum  supply  ______________  

Figure 6.3b

(b)

Lacunae

Lamellae

Nerve

Vein

Artery

Canaliculus

Osteocyte in a lacuna

Central canal

Chemical  Composi;on  of  Bone:  Organic  

•  Osteogenic  cells,  osteoblasts,  osteocytes,  osteoclasts  

•  ______________—organic  bone  matrix  secreted  by  osteoblasts  – Ground  substance  (proteoglycans,  glycoproteins)  – ______________  fibers  

•  Provide  tensile  strength  and  flexibility  

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Chemical  Composi;on  of  Bone:  Inorganic  

•  ______________  (mineral  salts)  – 65%  of  bone  by  mass  – Mainly  calcium  phosphate  crystals  – Responsible  for  ______________  and  resistance  to  compression