1. Skeleton: constructed of two types of connective
tissues: bone and cartilage
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support
protection
system of levers
storage of lipids and many minerals (calcium)
site for hematopoesis (red bone marrow blood cell production)

2. Cartilage (chondro-)
Also called soft Tissue.Present around the bone.
Cells:
• Chondroblast - actively mitotic cartilage cell
• Chondrocyte - mature cartilage cell, in lacunae
Three types of cartilage:
• Hyaline
• Elastic
• Fibrocartilage

3. Hyaline Cartilage
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most common type of cartilage (gristle)
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matrix = bluish-white if unstained
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very fine fibers (not visible with light microscope)
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contains lacunae (chambers) with chondrocytes (mature
cartilage cells)
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locations: articular surface of bones (ends of bones at
movable joints), end of nose, fetal skeleton, trachea, costal
cartilage
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functions: support and lubrication

4. Elastic Cartilage
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matrix contains numerous, visible elastic fibers (resilience and
flexibility)
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densely clustered lacunae with chondrocytes
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locations: ear pinna, epiglottis, Eustachian tube (auditory tube)
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functions: support and give shape
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Colour : yellowish in color

5. Fibrocartilage
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collagenous fibers are dominant feature of matrix
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thick compact parallel bundles with wavy appearance
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locations: intervertebral disks, pubic symphasis, knee menisci
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functions: strong compression and tension forces.
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Type of protein present in matrix is chondryomucoprotein.

7. Bone (osteo-)
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support
protection
movement
mineral storage
hematopoesis (blood cell formation)
contains vesicles, collagen fibers, protein matrix,
organic and inorganic materials
• Cells:
– osteoblast, osteocyte, osteoclast

8. Histology of Bone Tissue
Cells:
Osteoblast –it is site for production of mature bone cell
(osteocyte)
Osteocyte - mature bone cell, present in lacunae
Osteoclast – related to macrophages, secrete HCl to break
down calcium and phosphorous
• Compact Bone - dense, outer layer, found in diaphysis
• Spongy Bone (cancellous bone) - internal, spongy layer,
found in epiphysis

11. Microscopic Examination of Compact Bone
• functional unit of compact bone = osteon (Haversian
system)
• core of osteon = central canal (Haversian canal)
• central canal contains blood vessels to supply bone cells
• within osteon = osteocytes (mature bone cells) within
lacunae (chambers)
• thin tubes called canaliculi run between lacunae and
nearby capillaries
• rings called lamellae

13. Compact Bone - 400x magnification.

14. Microscopic Examination of Spongy Bone
• honeycomb of small needle-like pieces called trabeculae
• open spaces between trabeculae are filled with red and
yellow bone marrow
• each trabecula contains several layers of lamellae and
osteocytes in lacunae, but is too small to contain osteons
or vessels of its own

15. Spongy (Cancellous) Bone
The osteocytes are located within chambers (lacunae) inside the trabeculae. Red bone
marrow fills the spaces between trabeculae. 100x magnification.