the bone.pptx

7/29/2019 the bone.pptx

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BONE:

Like the cartilage; The bone is also special form ofconnective tissue which consist of cells, fibers and

extracellular matrix.Function of bone:

1-To protect the delicateorgans. Like brain and heart.

2-Formation of blood cells (hempoises).

3-Act as a reservoirs for several minerals like the calcium,phosphate, from which the body take it's requirements.


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Types of the bone:There are two types of the bone

1-Compact bone:

Which is usually form the outer cylindrical part of the long bone.

2-spongy bone:Form the inner surface of the compact bone and adjacent to thebone marrow cavity and consist of several inter connectingareas.

Marrow cavity:

This is present in the central part of the long bones in the new bornit is red and produce blood cells, while in adults normally it isyellow and filled with fat cells.

*Bone is surrounded from external surface by alayer of connective

tissue called periosteum. And from the internal surface lined bythe same layer called endosteum. *Both layers contain the osteoprogenitor cells


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Cells of the bone :The bone in adults contain four types of cells,these are :

cells present inundifferential.theseisIt:cellsOsteoprogenitor-1

the inner layer of periosteum and in the single layer ofendosteum.

These are present on the surface of the bone and:Osteoblasts-2synthesize , secret and deposit the new bone matrix.

t is principle cells of the bone and the mature:IOstecytes-3form of osteoblast present in the bone matrix inside thelacunae, it is branched cells, Their branches extend insidesmall ducts called the canalaculi and allow cell to cell andcell to blood vessels connection.

Large multinucleated cells found along the cell:Osteoclast-4surface, their function is resorption of the bone during theremodeling , it is locate on shallow depression called theHow ship's lacunae


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Bone fibers:

Bone contain collagen fibers which arrange in thin layers calledthe bone lamella, which form spherical structures contain

central canal contain blood vessels and nerves this calledHaversian canal.

Both lamella and haversian canal are called Haversian system(Osteon).

Bone Matrix: Contain organic material enable the bone to resist

the tension and inorganic compounds enable the bone toresist compression.

*Because the matrix of the bone is calcified therefore diffusionof nutrient is difficult therefore bone matrix is highly

vascularized and the blood vessels pass through longitudehaversian canal and transverse Volkmann's canal which jointhe central (Haversian) canal with the marrow cavity.


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Bone : compact bone

Haversian system

Haversian canal

Volkmanns canal


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Bone : compact bone

Haversian system

Haversian canal

Osteocyte

Bone lamellae


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Bone : compact bone

Volkmanns canal


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Bone : compact bone

Haversian system

Haversian canal

Volkmanns canal


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Bone : compact bone

Volkmanns canal

Canalaculi


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Bone : compact bone


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Bone : spongy bone

Bone trabiculae

Bone marrow


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Bone : spongy bone


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Bone : spongy bone

Osteocyte


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Bone : spongy bone

osteoblast


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Bone : spongy bone

the bone.pptx

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