Level 2 - Skeletal Development 2

Question 1

The process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation

Answer 1

Ossification (osteogenesis)

Question 2

What are the 2 processes resulting in the formation of normal, healthy bone tissue

Answer 2

Intramembranous ossification

Endochondral ossification

Question 3

-occurs with a connective tissue membrane, no cartilage present
Ex. Flat bones in skull, clavicle, mandible

Answer 3

Intramembranous ossification

Question 4

-bone formation from cartilage
Ex. Long bones

Answer 4

Endochondral ossification

Question 5

Where is the primary ossification Center always?

Answer 5

The shaft of a long bone

Question 6

Where is the secondary ossification centre always?

Answer 6

In the epiphysis of a long bone

Question 7

What 4 layers is the epiphyseal plate made of?

Answer 7

-resting cartilage cells
-zone of proliferation
-zone of hypertrophy
-zone of calcification

Question 8

Point of attachment joining the epiphysis to the shaft

Answer 8

“Resting” cartilage cells

Question 9

Cartilage cells undergoing active mitosis, which causes the layer to thicken and the plate to increase in length

Answer 9

Zone of proliferation

Question 10

Older, enlarged cells undergoing degenerative changes associated with calcium deposition

Answer 10

Zone of hypertrophy

Question 11

Dead or dying cartilage cells undergoing rapid calcification. Therefore, creating new bone tissue and bone grows in length

Answer 11

Zone of calcification

Question 12

Where does bone growth occur?

Answer 12

Added bone (new growth) is closer to the shaft side

Question 13

What is the process called where mature bone tissue is removed form the skeleton?

Answer 13

Bone resorption

Question 14

A life long process where mature bone is removed from skeleton and new bone tissue is formed

Answer 14

Bone remodeling

Question 15

T/F
Bone remodeling also responds to functional demands of the mechanical loading

Answer 15

True

As a result, bone is added where needed and removed where not needed

Question 16

T/F
In the first year of life, almost 100% of the skeleton is replaced

Answer 16

True

Question 17

How much of the skeleton is replaced each year in adults?

Answer 17

10%

Question 18

T/F
An imbalance in the regulation of bone remodelling (bone resorption and bone formation) may result in metabolic disease, such as osteoporosis

Answer 18

True

Question 19

T/F
Bones grow in length and diameter by the combined action of osteoclasts and osteoblasts

Answer 19

True
-osteoclasts enlargement the diameter of the medullary cavity and demineralize the tissue
-osteoblasts from the periosteum build new bone around the outside of the bone

Question 20

T/F
Mechanical stress strengthens bones (physical activity)

Answer 20

True

Question 21

T/F
Remodeling activity is important for blood calcium levels to be maintained as well as permitting bone growth in length and diameter, and the changing size of the medial part cavity

Answer 21

True

Question 22

What causes a fracture hematoma?

Answer 22

Fracture tearing and destroying blood vessels that carry nutrients to osteocytes

Question 23

Blood clot occurring immediately after the fracture, which is then absorbed and replaced by callus

Answer 23

Fracture hematoma

Question 24

Special repair tissue that binds the broken ends of the fracture together

Answer 24

Callus

Question 25

-avascular connective connective tissue
-has flexibility of firm plastic
-no canal system or blood vessels
-chondrocytes receive oxygen and nutrients by diffusion

Answer 25

Cartilage

Question 26

Fibrous covering of cartilage

Answer 26

Perichondrium

Question 27

Why do cartilage types differ?

Answer 27

-amount of matrix present
-amount of elastic and collagenous fibers

Question 28

-most common type of cartilage
-covers particular surfaces of bones
-forms the costal cartilages, cartilage rings in trachea, tip of nose
-forms from special cells in chondrificstion centers, which secrete matrix material
-chondrocytes are isolated into lacunae

Answer 28

Hyaline cartilage

Question 29

-large number of elastic fibers confers elasticity and resilience
-forms eat, epiglottis, eustachian tubes

Answer 29

Elastic cartilage

Question 30

-small quantities of matrix and abundant fibrous elements
-strong and rigid
-occurs in pubic symph. And intervertebral disks

Answer 30

Fibrocartilage

Question 31

-tough rubber like nature permits cartilage to sustain great weight or serve as shock absorber
-strong yet pliable support structure
-permits growth in length of long bones

Answer 31

Functions of cartilage

Question 32

-cartilage cells divide and secrete additional matrix
-seen during childhood and early adolescence while cartilage is still soft and capable of expansion from within

Answer 32

Interstitial or endogenous growth

Question 33

-chondrocytes in the deep layer of the perichondrium divide and secrete matrix
-new matrix is deposited on the surface, thereby increasing its size
-unusual in early childhood, but once initiated continues throughout life

Answer 33

Appositional or exogenous growth

Question 34

When is the Skelton fully ossified by?

Answer 34

Mid 20s
*soft tissue may continue to grow; ossifies more slowly

Question 35

The skeleton comprises of approximately how much compact and cancellous bone?

Answer 35

80% compact
20% cancellous

Question 36

Mature bone cells

Answer 36

Osteocytes

Question 37

T/F
Trabeculae provide the internal support structure of bone and are aligned along the direction of forces to provide tensile and compressive strength

Answer 37

True

Question 38

Process in which the red bone marrow produces red and white blood cells

Answer 38

Haematopoiesis

Question 39

T/F
Blood vessels do not enter or exit the bone at surfaces covered by articular hyaline cartilage

Answer 39

True