Lecture 5 - Bone Growth

Question 1

What are the basic steps from cartilage to mineralized tissue?

Answer 1

1. Start of calcification (turning into a more mineral aspect similar to what we get in normal bone)
2. Blood vessels and osteoblasts form bone on the surface of the cartilage
3. Blood vessels taking osteoblasts to the Centre to form a calcified matrix
4. Primary ossification centre developed (diaphysis or shaft of bone)

Question 2

The diaphysis are primary ossification Centre’s and the epiphyses remain cartilage when the primary ossification Centre has been developed. What is the secondary ossification Centre?

Answer 2

The epiphyses go through the same ossification process as primary centers and is separated from diaphysis by an epiphyses plate.

Question 3

What is another word for growth plate?

Answer 3

Epiphyseal plate

Question 4

What is the diaphysis?

Answer 4

The diaphysis is the internal structure of a human long (shaft) bone, with a magnified cross section of the interior. It is made up of cortical bone and usually contains bone marrow and adipose tissue (fat)

Question 5

What is cortical bone?

Answer 5

Cortical bone is the dense outer surface of the bone that forms a protective layer around the internal cavity - this is also known as contact bone.

Question 6

What is the process of transforming cartilage to bone called?

Answer 6

Endochondral ossification

Question 7

Growth in length is?

Answer 7

Through growth plate

Question 8

Growth in width is?

Answer 8

• Appositional growth (increase in the diameter of bones by the addition of bony tissue at the surface of our bones)
• Osteoblasts activity produces circumferential lamellae
• Osteocytes mould the bone shape and form the medullary cavity

Question 9

What is a joint?

Answer 9

A joint is where two bones meet (articulation) A joint involves bone shapes and soft tissues and allows free movement/ control of movement.

Question 10

What are the two types of cartilage associated with joints?

Answer 10

1. Hyaline (articular)

2. Fibrocartilage

Question 11

What is the general cartilage composition?

Answer 11

1. Collagen fibers in a ground substance, chondrocytes in lacuna
2. Blood vessels don’t penetrate cartilage
3. Nutrients diffused through matrix by joint loading

Question 12

What are the properties of Hyaline (articular) cartilage?

Answer 12

1. Collagen fibers are barely visible
2. High water content in matrix
3. Function = resist compression
4. Smooth, frictionless surface

Question 13

What is a chondrocyte?

Answer 13

A chondrocyte is a cartilage cell that occur at scattered sites through the cartilage and receive nutrition by diffusion through the gel

Question 14

What are the functions of hyaline cartilage in joints?

Answer 14

1. Mounds to surface our bones where they articulate
2. Frictionless, smooth movement
3. Degrades with age

Question 15

What are the properties of fibrocartilage?

Answer 15

1. Collagen fibers form bundles throughout matrix
2. Orientation of fibers aligns with stresses
3. Function = resist compression and tension

Question 16

What are the functions of fibrocartilage in joints?

Answer 16

1. Generally at articulations that experience both compression and tension
2. Deepening of articular surfaces
3. Acts as a buffer/shock absorber (distributed force over a wider area)

Question 17

What do ligaments do?

Answer 17

1. Connect muscle to bone
2. Facilitates and controls movement
3. Will restrict movement medi

Question 18

What do tendons do?

Answer 18

1. Connect muscle to bone
2. Facilitate and control movement
3. Contraction of muscles transmitted to bone

Question 19

What is bony congruence?

Answer 19

Bony congruence is the sum of the bone surfaces that form an articulation. Some joints need less support than other joints. Less congruence = more soft tissue to make joint stable

Question 20

What is tissue?

Answer 20

Cells grouped together in a highly organized manner according to specific structure and function

Question 21

What is structure?

Answer 21

Something formed of a tissue (e.g meniscus)

Question 22

What are the three types of joints based on the amount of movement possible and the tissue present?

Answer 22

1. Fibrous
2. Cartilaginous
3. Synovial

Question 23

What are fibrous joints?

Answer 23

The fibrous joint has dense fibrous connective tissue which forms ligaments. The structure of fibrous joints are ligaments and their function is to limit movement and provide stability. E.g cranial sutures

Question 24

What are cartilaginous joints?

Answer 24

Cartilaginous joints are more mobile than fibrous joints and have fibrocartilage as their tissue. They allow some movement, pressure and tension. They have various structures with special functions. E.g pubic symphysis (joint) two halves of pelvis

Question 25

What are synovial joints?

Answer 25

Synovial joints are free moving joints and are most limb joints. The amount of and direction is determined by joint structure