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33 terms

Ch.6 Introduction to the Skeletal System

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skeletal system
The entire framework of bones, their cartilages, along with ligaments and tendons.
Functions of the Skeletal System
1.support- the structural frame work
2. protection- protects sensitive internal organs
3.assistance in movement- allows muscular actions
4. mineral homeostasis-store calcium and other important minerals
5.blood cell production- all blood cells originate in red bone marrow
6.triglyceride storage- as we grow and age some red bone marrow becomes yellow bone marrow
Long Bones
distribute body weight, unevenly distributed, are slightly curved for strength, and absorbs the stress of the body weight.
Short Bones
length is equal, somewhat cube shaped, and nearly equal in length and width.
Flat Bones
are generally thin, provide protection, exstensive surfaces for muscle attachment.
Irregular Bones
complex shapes and cannot be grouped into any other bone category.
Sesamoid Bones
(patella) develope from stress in tendons, changes the angles of pull of a muscle, protects tendons from wear, and always completely ossified
Regions of a long bone 1. diaphysis
shaft of long bones
2. epiphyses
proximal and distal ends of the bone
2. metaphyses
the regions between the diaphysis and the epiphyses.
epiphyseal plate
a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length
epiphyseal line
when bone growth stops, the cartilage in the epiphyseal plate is replaced by this osseous tissue and results in this bony structure.
Surface tissues 1.articular cartilage
where the bone forms in articulation (joint) with another bone
2. Periosteum
a though sheath of dense regular connective tissue that surrounds the bone surface wherever its not covered by articular cartilage
3 Endosteum
thin connective tissue membrane that lines the medullary cavity it contains bone forming cells
medullar cavity
the hollow cylindrical space within the diaphysis that contains yellow bone marrow in adults
calcification
initiated by osteoblast
Osseous Tissue 1 osteogenic cells
unspecified stem cells derived from mescenchyme
2 osteoblast
synthesis / secretes collagen fibers and other organic compounds
3.osteocytes
mature bone cells, are the most numerous cells in osseous tissue and maintain its daily metabolism
4. osteoclasts
huge cells derived from the fusion of as many as 50 moncytes and are concentrated in the the endosteum
Compact bone
is the more dense of the two, providing much of the strength of long bones.
Perforating or Volkmann's canals
blood ,lymphatic vessels nerves from the periosteum penetrate the the compact bone tissue trough this canal
Central or Haversian canals
vessels in nerves connect with those of the periosteum
Concentric lamellae
this are rings of hard calcified extra cellular matrix
Lacunae
small spaces between the lamellae which contains osteocytes
Canaliculi
tiny and filled with extracelluar fluid
Osteons or Haversian systems
repeated structural units in compact bone tissue
Interstitial lamellae
fragments of older osteons that have been partially destroyed during bone rebuilding or growth
Circumferential lamellae
lamellae that encircle the bone just beneath the periosteum or encircle the medullary cavity
Spongy bone
has many large spaces. Spongy bone is the predominant tissue in flat bones, and is much stronger than it looks.
trabeculae
lamellae that are arranged in an irregular lattice of thin colums of bone
periosteal arteries
enter the diaphysis through numerous perforating canals and supply blood to the periosteum and outer parts of the compact bone tissue