Bone Tissue (2 webinars) Flashcards
what makes bone tissue specialized ?
it has a hard and calcified (mineralized) extracellular matrix . calcium salts are deposited in ground substance
what is the cell responsible for maintenance of bone ?
osteocytes
what are the main functions of the bone?
support and protect
provides levers for muscle ( muscle cannot work without bone )
stores calcium phosphorus minerals
red marrow inside bone is site for formation of blood cells (hematopoeisis )
describe the structure of the bone –0——–
the outer layer is covered by periostium
the inside is covered in a very thin layer called endostium
in between we will find the cells
osteocytes are present in the middle while the oseoblast are on the peripheral side of the inside of the cell
what is the periosteum ?
the outer cover layer of the bone . it is composed of external fibrous layer and inner vascularized layer ( osteoblasts , also known as osteo-progenitor layer )
what cell is responsible for healing fractures in bones?
osteo-progenitor cell
What are Sharpey’s fibers ?
the part of any fiber that penetrated the bone and binds to periosteum
describe the structure of the endosteum ,
it is the lining of internal surface of the bone .similar in function to periosteum but only 1 layer thick (one cell thick ) and it contains immature cells .
what type of collagen is present in bone fibers ?
collagen type 1
extra cellular matrix of bones is not fluid it is calcified and mineralized
70% crystalline complex of calcium and phosphorus and 30% collagen
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what are osteoblasts ?
immature cells responsible for formation of bone
they are always resting on un-minaralized tissue (bone)
what is the matrix of oseoblasts made of?
glycoprotein and collagen
what are osteocytes ?
mature bone cell responsible for maintaining matrix and health of bone.
they rest on and are surrounded by lacuna ( cytoplasmic extension to communicate with other type of cell)
what is the lacunae?
cytoplasmic extension to communicate with other type of cell
what are ossteoclasts ?
the cell responsible for resorbing of bone
it is large
has multiple nucli
contains acids
where does the embryonic connective tissue originate from ?
mesoderm / mesenchyme
what is ossification and what are the 2 types?
it is the formation of bone . the two types are intramembranous ossification and endochondral ossification
what is the difference between intramembranous and endochondral ossification ?>
in intramembranous ossification the body draws a membrane in the shape of the desired bone ( by the mesoderm’s ) and then osteoblasts start to differentiates and form the bone inside the membrane . ( no cartilage needed)( flat bones of skull , maxilla)
in endochondral ossification a cartilage grows and the deep layer converts into bone . classification of the bone happens inside cartilage . ( vertebral column , long bones in limbs )
what types of ossification does the mandible have ?
both intra membranous(body of mandible) and endochondral ossification (coronoid process and condylar process)
which part of the mandible has intramembranous ossification ?
the body of the mandible .
what part of the mandible has endochondral ossification ?
the coronoid and the condylar process
what is the cartilage in endochondral ossification made of ?
chondroblast
what is a lamelar bone
bone arranged in layer
what are the 2 types of lamelar bone ?
compact bone and spongy bone
