Ch 7 – Skeletal System Notes

Components of the bones... Bone tissue Cartilage Dense connective tissue Blood Nervous tissue

Functions of the bones... Attach to muscles Protect and support softer tissues House blood-producing cells Store inorganic salts Form passageways for blood vessels and nerves

Bone Classification Bones are classified according to shape: Long bones Short bones Flat bones Irregular bones Sesamoid/Round bones

Parts of a Long Bone Examples: femur On the ends: epihyses - forms a joint with another bone. Proximal vs distal Made of spongy bone Covered by articular cartilage Area between epiphyses: diaphysis Made 0f compact bone Covered by periosteum Firmly attached Continuous with ligaments and tendons Helps form and repair bone tissue Epiphysis; spongy bone; articular cartilage; diaphysis; compact bone; periosteum

Compact vs Spongy bone Pg 134 Fig 7.2 Compact Spongy bone Continuous extracellular matrix with no spaces. Spongy bone Conatins trabeculae Reduces bone’s weight In the middle... Medullary cavity Lined by spongy bone Filled by marrow Trabeculae; weight;

Microscopic Structure Bone cells are called osteocytes Compact They form circles of lacuna around central canal. The circular shapes are osteons Central canal contains blood vessels and nerves. Spongy No osteons

Development and Growth Bone development starts within the first few weeks of conception. Two ways bones form: Intramembranous bones Endochondral bones Ossification – the formation of bone Formation of a bone

Intramembranous Bones Skull First forms as connective tissue. Progenitor cells become osteoblasts. Forms spongy bone tissue in all directions. Osteocytes on the outside form compact bone. Connective tissue; osteoblasts; spongy; compact bone

Endochondral Bones Most bones Start as masses of hyaline cartilage Steps Six steps – pg. 136 Hyaline cartilage; diaphysis; periosteum; blood vessels, spongy; compact

Bone function Four main functions Support/Protect – Give Shape; marrow and blood vessels; stores fat (yellow marrow) Body Movement – attach muscles; act as levers Blood Cell Formation – hematopoiesis; red marrow (RBCs, WBCs, platelets) Storage of Inorganic Salts – Calcium; negative feedback mechanism

Quizzes over bones 7.1/7.3 – Bone structure 7.9 – Axial/Appendicular 7.10/7.12/7.13/7.14/7.15 – Skull 7.21 – Thoracic Cage

Journal 2/21 What is the difference in the axial and appendicular skeletons? What kind of developmental bones become part of the skull?

Joints – Sec 7.13 Another word for joints is ______________. Two forms of classification: Movement Immovable (synarthrotic), slightly movable (amphiarthrotic), or freely moveable (diarthrotic). Type of tissue Fibrous, Cartliaginous, or Synovial

Fibrous Joints Joints that closely contact one another Layer of dense connective tissue in between Generally immovable (synarthrotic) Some have limited movement

Cartilaginous Joints Connected by hyaline cartilage Absorbs shock and equalizes pressure Limited movement (amphiarthrotic)

Synovial Joints Most joints in the skeletal system Free movement (diarthrotic) More complex Hyaline cartilage, dense connective tissue Contains synovial fluid Some conatin menisci – flattened, shock-absorbing pads of fibrocartilage. Some contain bursae – fluid- filled sacs Six different categories