Chapter 7
Skeletal Tissues
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Slide 1
Types of Bones
Structurally, there are four types of bones
Long bones
Short bones
Flat bones
Irregular bones
Bones serve various needs, and their size,
shape, and appearance will vary to meet
those needs
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Slide 2
Types of Bones
Bones vary in their proportions of compact
and cancellous (spongy) bone; compact bone
is dense and solid in appearance, whereas
cancellous bone is characterized by open
space partially filled with needle-like
structures
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Slide 3
Types of Bones
Parts of a long bone
Diaphysis
• Main shaft of long bone
• Hollow, cylindrical shape and thick,
compact bone
• Function is to provide strong support without
cumbersome weight
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Slide 4
Types of Bones
Parts of a long bone
Epiphyses
• Both ends of a long bone, made of cancellous
bone filled with marrow
• Bulbous shape
• Function is to provide attachments for muscles
and give stability to joints
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Slide 5
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Slide 6
Types of Bones
Parts of a long bone
Articular cartilage
• Layer of hyaline cartilage that covers the articular surface
of epiphyses
• Function is to cushion jolts and blows
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Slide 7
Types of Bones
Parts of a long bone
Periosteum
• Dense, white, fibrous membrane that covers bone
• Attaches tendons firmly to bones
• Contains cells that form and destroy bone
• Contains blood vessels important in growth and repair
• Contains blood vessels that send branches into bone
• Essential for bone cell survival and bone formation
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Slide 8
Types of Bones
Parts of a long bone
Medullary (or marrow) cavity
• Tubelike, hollow space in diaphysis
• Filled with yellow marrow in adult
Endosteum—thin epithelial membrane that lines
medullary cavity
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Slide 9
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Slide 10
Types of Bones
Short, flat, and irregular bones
Inner portion is cancellous bone, covered on the
outside with compact bone
Spaces inside cancellous bone of a few irregular
and flat bones are filled with red marrow
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Slide 11
Bone Tissue
Most distinctive form of connective tissue
Extracellular components are hard and
calcified
Rigidity of bone allows it to serve its
supportive and protective functions
Tensile strength is nearly equal to cast iron at
less than one third the weight
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Slide 12
Microscopic Structure of the Bone
Compact bone
Contains many cylinder-shaped structural units called
osteons, or Haversian systems
Osteons surround canals that run lengthwise through bone
and are connected by transverse Volkmann’s canals
Living bone cells are located in these units, which constitute
the structural framework of compact bone
Osteons permit delivery of nutrients and removal
of waste products
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Slide 13
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Slide 14
Microscopic Structure of the Bone
Compact bone
Four types of structures make up each osteon:
• Lamella—concentric, cylinder-shaped layers of calcified
matrix
• Lacunae—small spaces containing tissue fluid in which
bone cells are located between hard layers of the lamella
• Canaliculi—ultrasmall canals radiating in all directions
from the lacunae and connecting them to each other and
to the Haversian canal
• Haversian canal—extends lengthwise through the center
of each osteon and contains blood vessels and lymphatic
vessels
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Slide 15
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Slide 16
Microscopic Structure of the Bone
Cancellous bones
No osteons in cancellous bone; instead, it has
trabeculae
Nutrients are delivered and waste products
removed by diffusion through tiny canaliculi
Bony spicules are arranged along lines of stress,
enhancing the bone’s strength
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Slide 17
Microscopic Structure of the Bone
Blood supply
Bone cells are metabolically active and need a
blood supply, which comes from the bone marrow
in the internal medullary cavity of cancellous bone
Compact bone, in addition to bone marrow and
blood vessels from the periosteum, penetrate
bone and then, by way of Volkmann’s canals,
connect with vessels in the Haversian canals
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Slide 18
Microscopic Structure of the Bone
Types of bone cells
Osteoblasts
• Bone-forming cells found in all bone surfaces
• Small cells synthesize and secrete osteoid, an important
part of the ground substance
• Collagen fibrils line up in osteoid and serve as a
framework for the deposition of calcium and phosphate
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Slide 19
Microscopic Structure of the Bone
Types of bone cells
Osteoclasts
• Giant multinucleate cells
• Responsible for the active erosion of bone minerals
• Contain large numbers of mitochondria and lysosomes
Osteocytes—mature, nondividing osteoblast
surrounded by matrix, lying within lacunae
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Slide 20
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