Chapter 7
Skeletal Tissues
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Slide 1
Types of Bones


Structurally, there are four types of bones

Long bones
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Short bones
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Flat bones
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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
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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
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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
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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
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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
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Extracellular components are hard and
calcified
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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
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Compact bone

Contains many cylinder-shaped structural units called
osteons, or Haversian systems
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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
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Cancellous bones
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No osteons in cancellous bone; instead, it has
trabeculae
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Nutrients are delivered and waste products
removed by diffusion through tiny canaliculi
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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
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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
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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