Bone, joints and soft tissue Flashcards
(70 cards)
Bone matrix is composed of
an organic component known as osteoid (one third wet weight) and a mineral component (two thirds)
Osteoid composed of
Type I collagen, GAG, proteins
What are specialized cells in bone?
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteoblasts
Located on surface of matrix, synthesize, transport and assemble bone matrix and regulate its mineralization
Osteocytes
located within the bone in lacunae
Osteoclasts
Located on the surface of bone, are specialized multinucleated macrophages. Responsible for bone resorption
Bone formation- During embryogenesis, long bones develop from a
cartilage mold by the process of endochondral ossification
Intramembranous ossification, by contrast, is responsible for development of
flat bones
Newly developed bone is
woven bone
Woven bone
Rapidly formed, more cellular, has random orientation, is only produced physiologically until the end of puberty
Compact (cortical) bone is organized as
parallel columns, known as Haversian systems, which run lengthwise down the axis of long bones
Columns in compact bone are composed of
lamellae, concentric rings of bone, surrounding a central channel, or Haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone
Parallel Haversian canals are connected to one another by the
perpendicular Volkmann’s canals
The lamellae of the Haversian systems are created by
osteoblasts
As osteoblasts secrete matrix, they become trapped in spaces called lacunae and become known as
osteocytes
Osteocytes communicate with the Haversian canal through
cytoplasmic extensions that run through canaliculi (interconnecting canals)
Osteogenesis Imperfecta
Type I collagen disease
How can osteogenesis imperfecta manifest orally?
Teeth are small, misshapen, blue-yellow
Dentinogenesis imperfecta Type I, the teetha re
discolored and show structural defects such as bulbous crowns and small pulp chambers radiographically
What is marble bone disease called?
Osteopetrosis
What is osteopetrosis?
Group of inherited disorders caused by a defect in osteoclastic
activity
In osteopetrosis, bone continues to be laid down with
minimal resorption- woven bone, no remodelling
In osteopetrosis, net gain in bone results in
thickened bone, heavily mineralzied and also brittle
osteopetrosis AD form is
benign-mild, Dx in adolescence or young adults, fractures, cranial nerve problems, infections
