Flashcards in Development and growth of bone Deck (23)
What are some of the functions of bone?
Support of the body shape
Systems of levers for muscle action
Protection of internal organs
Site of blood cell formation
Mineral storage pool
What are the two mechanical properties of bone and what is responsible for these properties?
Cable-like flexibility – and resistance to tension because the framework is collagen and other bone proteins (osteoid)
Pillar-like stiffness – and resistance to compression conferred by impregnation of collagen with crystalline mineral (hydroxyapatite – a complex calcium hydroxyphosphate)
What are the two main types of bone tissue?
When is woven bone found in adults?
It is only found in repairing fractures
What is the technical term for the shaft of a bone?
What is the technical term for the head of a bone?
What type of bone is found around the outside of the bone?
What is the term given to the cavity within the bone?
Medullary cavity (contains bone marrow)
What type of bone is found within this cavity?
Trabecular/spongy/cancellous bone (this is still lamellar bone)
What units is lamellar bone in the compact bone arranged into?
They have a central canal containing vessels and around the vessels you have concentric layers of bone maintained by concentrically arranged osteocytes
In what planes are these units arranged?
They are usually organised along pressure planes
What provides the main blood supply to the bone marrow?
Nutrient artery (passing through the nutrient foramen)
What are the two layers of the periosteum?
What are the main roles of the periosteum?
Bone growth and repair
It is vascular
It has a good sensory nerve supply
What do osteogenic cells give rise to?
Osteogenic cells Osteoblasts Osteocytes
What lineage do osteoclasts come from?
They are derived from the immune cell lineage – they are modified macrophages
At what point in fetal life does the skeleton start to develop?
What are the two types of ossification?
Describe intramembranous ossification.
Occurs within existing vascular connective tissue
Bone matrix (ostein) is deposited around the collagen
This mineralises to form woven bone
It then remodels to form lamellar bone
Describe endochondral ossification.
Occurs within existing fetal cartilage models
Cartilage calcifies and the chondrocytes die
Periosteal osteoclasts cut channels for sprouting vessels
Osteoblasts enter with the vessels to build bone around them
List some bones in which intramembranous ossification takes place.
Part of the clavicle
At what point do the epiphyses ossify in a child’s wrist?