Structure and Function of Bone Lab

Question 1

What is the osteon?

Answer 1

Functional unit of bone

Question 2

What is the central canal of osteons for?

Answer 2

For blood vessels to pass through

it can also be called the haversian canal

Question 3

What forms the osteon?

Answer 3

Circular layers of bone containing trapped osteocytes

Question 4

What is the trabeculae useful for and what occupies the spaces between it during life?

Answer 4

• Helps to transfer weight through the bone

- Filled with bone marrow

Question 5

What does bone need collagen for?

Answer 5

To be less brittle, for tensile strength

Question 6

What does bone need mineral for?

Answer 6

For compressive strength and stiffness

Question 7

What could cause the bone to be able to be tied in a knot?

Answer 7

Bone is decalcified.

Ca hydroxyapatite needed for compressive strength

Question 8

What can cause bowing of lower limbs eg. rickets?

Answer 8

Lack of vit D or lack of Ca in diet.
Vid D needed for Ca absorption.
Ca needed in bone for compressive strength.

Question 9

How could you tell a bone had been burnt?

Answer 9

-White calcified areas

Question 10

What will burining of bones destroy, why is this significant?

Answer 10

• Cells and collagen.

- It will leave only the inorganic matrix.

Question 11

What causes increases susceptibility to fractures in OI?

Answer 11

Congenital disorder

-Mutations in genes affecting collagen 1 formation

Question 12

Where will cancellous bone be found in the femur?

Answer 12

• Principally at lower and upper ends

- Shaft much more hollow with relatively few trabeculae.

Question 13

In life, what occupies hollow medulla space of femur?

Answer 13

• Red bone marrow occupies spaces between trabeculae in kids, in adults it turns to fat.
• Cavity of shaft occupied by yellow marrow.

Question 14

What is the pattern of trabeculae at the upper end of femur and why?

Answer 14

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.

Question 15

Why is shaft hollow in fibia?

Answer 15

• 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

Question 16

In the femur, how are trabeculae arranged at lower end and why?

Answer 16

Relatively regular lattice work

Gives even weight spread across upper end of tibia at knee joint.

Question 17

What types of growth are bone and cartilage able to do and what are they?

Answer 17

• Bone = appositional (results in bone thickening)

- Cartilage = appositional and interstitial (produces longer bones)

Question 18

How does cartilage recieve its nutrients as it is avascular?

Answer 18

By diffusion

Question 19

What are the 5 zones of the growth plate?

Answer 19

• Resting layer
• Zone of proliferation
• Zone of hypertrophy
• Zone of calcification
• Blood vessels

Question 20

What occurs at resting layer of growth plate?

Answer 20

-Reserve chondrocytes here which replicate slowly

Question 21

What occurs at the zone of proliferation of growth plate?

Answer 21

Cells divide more rapidly and line up in rows along long axis of bone

Question 22

What occurs at the zone of hypertrohy of growth plate?

Answer 22

Chondrocytes mature and expand in size

Question 23

What occurs at zone of calcification of growth plate?

Answer 23

Expanded cells become calcified and die via apoptosis.

Calcified matrix forms structure for bone to be laid down.

Question 24

What occurs at BLOOD VESSELS of growth plate?

Answer 24

Blood vessels and bone cells invade calcified cartilage and begin to replace structure with bone.

Question 25

What type of tissue forms the growth plate?

Answer 25

Hyaline cartilage

Question 26

When will a bone stop growing in length?`

Answer 26

When cartilage growth plate stops proliferating and is replaced entirely by bone.

Question 27

What is ossification?

Answer 27

The process by which bone is made

Question 28

What is enchondral ossification?

Answer 28

When a cartilage model is made 1st then replaced by bone.

Question 29

What is intramembranous ossification?

Answer 29

Bone formed directly in mesenchyme

Question 30

What is the primary ossification centre?

Answer 30

A primary ossification center is the first area of a bone to start ossifying.
In long bones the primary centers occur in the diaphysis

Question 31

What is the secondary ossification centre in long bones?

Answer 31

Epiphysis

Question 32

What are fontanelles and why are they important in development?

Answer 32

Soft spots where bone hasnt fused yet.

Important as they allow flexibility during birthing and rapid brain growth during early life.

Question 33

What ways can finding out someones skeletal age be useful?

Answer 33

To detect sports fraud

Working out immigrants age

Question 34

How would osteophytes and calcification/ossification of ligaments affect movement?

Answer 34

Pain and stiffness, severe cases may effect spinal cord or nerves which would cause numbness/weakness in limbs.

Question 35

What may cause periostitis?

Answer 35

Inflammation of periosteum

-Infection eg. staph bacteria, congenital syphilis, trauma