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Basic tissues- slideshow 4
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- 1Functions of Bone and the Skeletal SystemBone is the primary tissue of the skeleton
- 2Why is the skeleton important?Why is the skeleton important?
- Support
- Movement: muscle attachment
- Protection: Cavities and organs, e.g. skull
- Calcium homeostasis:There is a constant exchange of calcium
between blood and bones (to facilitate
nerve conduction, muscle contraction, etc.) A typical human body has 1–2kg of Calcium
98+% is deposited in bone
- Storage: Bone stores red and yellow marrow Red marrow → haematopoiesis - 3Facts about bonesBone is alive and metabolically active
• It is an organ • It is highly vascular
(unlike cartilage)
• It is constantly being remodelled: a balance between bone formation by osteoblasts and bone resorption by osteoclasts • Damaged bone is
replaced by newly synthesised bone
• Periosteum has an outer layer of dense,
irregular connective tissue (DICT) and an
inner layer of osteoprogenitor cells - 4What do osteocytes occupylacunae
Lacunae connect to each other and
to blood vessels through canaliculi - 5What does compact bone consist ofosteons
Osteons are cylindrical structures
of concentric lamellae of bone
matrix around a central
(Haversian) canal containing
blood vessels and nerves - 6What canals connect the central canals with periosteum and marrowPerforating (Volksmann) canals
-Fibres in the lamellae are
parallel with each other, but run
in different directions in adjacent
lamellae, which confers strength - 7Bone structure 1Periosteum is a tough, vascularized,
fibrous sheath that superficially
covers parts of bone where there is
no cartilage
• It nourishes and protects the bone
• It forms an attachment site for
ligaments and tendons
• Superficial layer high on fibres
• Deep layers have osteogenic
(bone forming) cells for bone repair - 8The Structure of Bone 2Endosteum is a thin membrane that lines
the medullary cavity.
• Single layer of bone-forming (osteoprogenitor) cells
• Sparse matrix of collagen fibers
The medullary cavity is a hollow cavity containing bone marrow.
• It minimizes the weight of the bone where it is least needed. - 9The Composition of Bone Tissue: MatrixOrganic Matrix: Dry Weight = 35%
• Type I Collagen • Proteoglycans (PGs) and glycosaminoglycan (GAGs)
• Glycoproteins: Osteonectin and osteocalcin
Inorganic Matrix: Dry Weight = 65%
• Calcium Phosphate → Hydroxyapatite
• Hardness, compressive strength Ca10(PO4)6(OH)2 - 10OsteocyteMature bone cell that maintains and monitors the protein content of the matrix; signals stress
- 11Osteoprogenitor cellA stem cell that differentiates from mesenchyme and divisions of which produces osteoblasts
- 12OsteoblastImmature bone cell that secretes organic components of the matrix in the process of osteogenesis
- 13OsteoclastA large multinucleate cell derived from monocytes which secretes acids and enzymes to dissolve bone matrix( releasing Ca2+) in the process of osteolysis
- 14—
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- Medicine Fichas sobre Basic tissues- slideshow 4, creado por i i el 14/12/2022.
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- i i
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