Skeletal System = 206 bones, three types of cartilage, ligaments.
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The body
Skeletal System = 206 bones, three types of cartilage, ligaments.
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I. Functions:
1) Support of soft tissues. Bones provide shape and form, supporting
against gravity.
2) Protection of vital organs: cranium, sternum and ribs, vertebral
column.
3) Movement. Bones act as the levers the muscles contract against.
4) Storage:
a) adipose – yellow marrow in long bones
b) calcium salts – forms solid matrix of bones
5) blood cell production in red marrow.
II. Bone matrix components
1 . Non-cellular (secreted by bone cells)
collagen fibers
calcium salts.
2 . cellular (bone cells)
matrix originally produced by osteoblasts,
matrix maintained by osteocytes (osteoblasts that continue to deposit bone matrix
a lower levels),
matrix dissolved by osteoclasts
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III. BoneHistology:
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A) Compact Bone tissue
matrix deposited into microscopic Osteons- They are circular rings of calcium
salts, resembling
the annual rings of a tree.The osteocytes are in spaces called lacunae.
Forms the diaphyses of long bones, forms a thin layer covering the epiphyses,
and forms a thin layer
on the outside of flat, short, and irregular bones.
B) Spongy Bone tissue
matrix deposited into trabeculae, bony, needlelike fragments.
The trabeculae form a sort of lattice, with many spaces. The spaces are filled
with red bone marrow (fat and red blood cells). Red bone marrowis the site of
hemopoiesis.
This tissue is found in the interior of flat, short, irregular bones, and epiphyses.
IV Gross Anatomy of bones
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1) all bones have following structure
a) periosteum membrane surrounds most of bone -contains bone forming/dissolving
cells
b) external layer of dense compact bone tissue
c ).inside consists of spongy bone tissue
d) blood vessels penetrate into interior of bone
2 ) Long Bones have additional structure
a) Diaphysis = the long, narrow shaft
b) Medullary Cavity= hollow cavity in diaphysis that is filled with yellow marrow (fat, adipose tissue)
c) Epiphyses: the expanded ends that articulate with adjacent bones.
- A thin layer of compact bone covering spongy bone- Filled with red marrow.(fat and red blood cells)
d) Articular Cartilage: hyaline cartilage.
- Located at joints to provide cushioning of movements.
e) Epiphyseal Plates: hyaline cartilage.
- A growth elongation zone between each epiphysisand the diaphysis.
- Human Growth Hormone promotes cell division here.During adulthood, it ossifies
and becomes
the epiphyseal line.
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A
web activity
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Professor Thomas M. Lancraft
Human Anatomy Courses
at St. Petersburg College
St. Petersburg/Gibbs Campus
5/2006