Structure and Function of Bone Lab Flashcards
What is the osteon?
Functional unit of bone
What is the central canal of osteons for?
For blood vessels to pass through
it can also be called the haversian canal
What forms the osteon?
Circular layers of bone containing trapped osteocytes
What is the trabeculae useful for and what occupies the spaces between it during life?
- Helps to transfer weight through the bone
- Filled with bone marrow
What does bone need collagen for?
To be less brittle, for tensile strength
What does bone need mineral for?
For compressive strength and stiffness
What could cause the bone to be able to be tied in a knot?
Bone is decalcified.
Ca hydroxyapatite needed for compressive strength
What can cause bowing of lower limbs eg. rickets?
Lack of vit D or lack of Ca in diet.
Vid D needed for Ca absorption.
Ca needed in bone for compressive strength.
How could you tell a bone had been burnt?
-White calcified areas
What will burining of bones destroy, why is this significant?
- Cells and collagen.
- It will leave only the inorganic matrix.
What causes increases susceptibility to fractures in OI?
Congenital disorder
-Mutations in genes affecting collagen 1 formation
Where will cancellous bone be found in the femur?
- Principally at lower and upper ends
- Shaft much more hollow with relatively few trabeculae.
In life, what occupies hollow medulla space of femur?
- Red bone marrow occupies spaces between trabeculae in kids, in adults it turns to fat.
- Cavity of shaft occupied by yellow marrow.
What is the pattern of trabeculae at the upper end of femur and why?
It converges on the cortical bone at the medial and lateral sides of the shaft.
-Transmits forces from femur head to cortical bone of shafts.
Why is shaft hollow in fibia?
- Need to be narrow to allow unrestricted thigh movement
- For a given amount of material, a hollow cylinder is stronger than a solid bar.
- Central cavity also important in blood supply
In the femur, how are trabeculae arranged at lower end and why?
Relatively regular lattice work
Gives even weight spread across upper end of tibia at knee joint.
What types of growth are bone and cartilage able to do and what are they?
- Bone = appositional (results in bone thickening)
- Cartilage = appositional and interstitial (produces longer bones)
How does cartilage recieve its nutrients as it is avascular?
By diffusion
What are the 5 zones of the growth plate?
- Resting layer
- Zone of proliferation
- Zone of hypertrophy
- Zone of calcification
- Blood vessels
What occurs at resting layer of growth plate?
-Reserve chondrocytes here which replicate slowly
What occurs at the zone of proliferation of growth plate?
Cells divide more rapidly and line up in rows along long axis of bone
What occurs at the zone of hypertrohy of growth plate?
Chondrocytes mature and expand in size
What occurs at zone of calcification of growth plate?
Expanded cells become calcified and die via apoptosis.
Calcified matrix forms structure for bone to be laid down.
What occurs at BLOOD VESSELS of growth plate?
Blood vessels and bone cells invade calcified cartilage and begin to replace structure with bone.
What type of tissue forms the growth plate?
Hyaline cartilage
When will a bone stop growing in length?`
When cartilage growth plate stops proliferating and is replaced entirely by bone.
What is ossification?
The process by which bone is made
What is enchondral ossification?
When a cartilage model is made 1st then replaced by bone.
What is intramembranous ossification?
Bone formed directly in mesenchyme
What is the primary ossification centre?
A primary ossification center is the first area of a bone to start ossifying.
In long bones the primary centers occur in the diaphysis
What is the secondary ossification centre in long bones?
Epiphysis
What are fontanelles and why are they important in development?
Soft spots where bone hasnt fused yet.
Important as they allow flexibility during birthing and rapid brain growth during early life.
What ways can finding out someones skeletal age be useful?
To detect sports fraud
Working out immigrants age
How would osteophytes and calcification/ossification of ligaments affect movement?
Pain and stiffness, severe cases may effect spinal cord or nerves which would cause numbness/weakness in limbs.
What may cause periostitis?
Inflammation of periosteum
-Infection eg. staph bacteria, congenital syphilis, trauma
