L3 - Bone Development - Articulate H

Question 1

There are two types of ossification (aka) Osteogenesis: What are they?

Answer 1

1. Intramembranous ossification

2. Endochondral ossification

Question 2

What is bone embryologically derived from?

Answer 2

Mesenchyme

Question 3

In which type of ossification do bone cells differentiate directly from mesenchymal cells to become osteoid?

Answer 3

Intramembranous ossification

Question 4

Which type of ossification gives rise to flat bones found in the head and face at around week 8 of gestation?

Answer 4

Intramembranous ossification

Question 5

Intramembranous ossification uses hyaline cartilage model precursor or not?

Answer 5

It does not

Question 6

Endochondral ossification uses hyaline cartilage model precursor or not?

Answer 6

It does

Question 7

Which type of ossification leads to the production of most short and long bones in the body?

Answer 7

Endochondral ossification

Question 8

What week does endochondral ossification take place through gestation? when are they present in the long bones of the body?

Answer 8

Starts in week 6 and visible in long bones by week 12

Question 9

What are the steps of intramembranous ossification?

Answer 9

1. Development of the ossification center
2. Calcification
3. Woven bone and periosteum development
4. Replacement of woven bone

Question 10

What happens during the development of ossification center stage of intramembranous ossification?

Answer 10

mesenchymal cells cluster, they change into osteoprogenitor cells, and they become more and more basophilic as they become osteoblasts.

Question 11

Osteoblasts secrete what?

Answer 11

Osteoid

Question 12

What happens during the calcification stage of intramembranous ossification?

Answer 12

Calcium and other mineral salts are deposited around collagen fibers, giving rise to osteocytes

Question 13

Osteoblasts that trap themselves in their calcifying osteoid are called what? and what do they sit in?

Answer 13

Osteocytes, lacunae

Question 14

What happens during the woven bone and periosteum development stage of intramembranous ossification?

Answer 14

Primary bone is being made, growth along the surfaces, bone is woven together. The bone on the periphery condenses and forms periosteum

Question 15

During woven bone and periosteum development what happens with the blood vessels that weave through the developing bone?

Answer 15

They become red bone marrow

Question 16

What happens during the replacement of woven bone during intramembranous ossification?

Answer 16

Woven bone is replaced by lamellar bone forming compact and spongy bone

Question 17

Flat bones are spongy or compact bone?

Answer 17

Both, they are spongy inside and compact on the outer layers

Question 18

What are the characteristics of osteoblasts?

Answer 18

Cuboidal shape and very basophilic

Question 19

Is woven bone organized or disorganized?

Answer 19

Disorganized

Question 20

What tissue does bone develop directly from in intramembranous ossification?

Answer 20

Mesenchyme

Question 21

Which of the following bones develops through intramembranous ossification?

a. Femur
b. Parietal bone
c. Phalanges

Answer 21

Parietal bone

Question 22

What replaces mesenchyme during endochondral ossification?

Answer 22

Hyaline cartilage

Question 23

What replaces hyaline cartilage during endochondral ossification?

Answer 23

Bone

Question 24

What is the first step of endochondral ossification?

Answer 24

1. Development of the fetal cartilage model

Question 25

What is the second step of endochondral ossification?

Answer 25

2. Bone collar forms around the diaphysis and cartilage of the shaft begins to calcify

Question 26

What is the third step of endochondral ossification?

Answer 26

3. Development of a primary ossification center in the diaphysis

Question 27

What is the fourth step of endochondral ossification?

Answer 27

4. Development of the secondary ossification centers

Question 28

What is the fifth step of endochondral ossification?

Answer 28

5. Retention of hyaline cartilage as the articular cartilage and the epiphyseal plate

Question 29

What is the sixth (last) step of endochondral ossification?

Answer 29

6. Epiphyseal plates ossify and form the epiphyseal lines

Question 30

At which stage of endochondrial ossification is mesenchyme differentiating into chondroblasts that secrete matrix and produce the hyaline cartilage model?

Answer 30

1. During development of the fetal cartilage model

Question 31

During development of the fetal cartilage model what type of growth occurs because of the chondrocytes and activity of the chondroblasts on the surface?

Answer 31

Interstitial growth giving rise to the perichondrium

Question 32

At which stage of endochondral ossification is the perichondrium becoming periosteum due to osteoblasts creating the first bone tissue to appear?

Answer 32

2. Bone collar forming around the diaphysis and cartilage of the shaft beginning to calcify

Question 33

What happens to oxygen and nutrients to the underlying cartilage as bone starts to develop?

Answer 33

The oxygen and nutrients are impeded upon because of the bone

Question 34

What causes the chondrocytes to slowly die off?

Answer 34

The calcification of bone stops the chondrocytes from receiving nutrients via diffusion.

Question 35

The absence of ______ causes the matrix to break down and calcified hyaline cartilage is created in the shaft.

Answer 35

Chondrocytes

Question 36

Primary bone is eosinophilic or basophilic?

Answer 36

Primary bone is eosinophilic

Question 37

Calcified bone is eosinophilic or basophilic?

Answer 37

Calcified bone is basophilic

Question 38

What causes the development of bone marrow as well as creates primary ossification centers?

Answer 38

Blood vessels

Question 39

Where is the main site for the primary ossification center ?

Answer 39

In the diaphysis

Question 40

Where are the secondary ossification centers located?

Answer 40

In the epiphysis

Question 41

What happens to chondrocytes in the development of secondary ossification centers?

Answer 41

They die off due to the compressing matrix, giving rise to spaces for blood vessels

Question 42

What does hyaline cartilage on the end of the bone model become? What is the function?

Answer 42

It becomes articular cartilage for the cushioning of bones

Question 43

The hyaline cartilage that remains between the diaphysis and the epiphysis has which function?

Answer 43

Acting as a growth plate for long bones

Question 44

At the end of puberty what happens to the epiphyseal cartilage?

Answer 44

It is replaced by bone forming the epiphyseal line

Question 45

What kind of ossification is used to lengthen long bone at the epiphyseal plate?

Answer 45

Endochondral ossification

Question 46

What are the 5 zones of the hyaline cartilage in the epiphyseal plate?

Answer 46

1. Resting cartilage 2. Proliferating cartilage 3. Hypertrophic cartilage 4. Calcified cartilage 5. Ossification

Question 47

The zone of resting cartilage is closest to epiphysis or diaphysis?

Answer 47

Epiphysis

Question 48

The zone of ossification is closest to epiphysis or diaphysis?

Answer 48

Diaphysis

Question 49

Which zone are chondrocytes alone or in small groups? No mitosis is happening and the matrix is inactive.

Answer 49

Zone of resting cartilage

Question 50

Which zone has chondrocytes undergoing mitosis creating matrix and causing the bone to lengthen?

Answer 50

Zone of proliferation (Zone of proliferating cartilage)

Question 51

In which zone do chondrocytes undergo hypertrophy, cytoplasm accumulates glycogen, and the matrix is compressed/thinned?

Answer 51

Zone of hypertrophy (Zone of hypertrophic cartilage)

Question 52

What happens to the chondrocytes in the zone of calcified cartilage as the cartilage calcifies?

Answer 52

They die because of the lack of nutrients through diffusion

Question 53

In which zone do small blood vessels, osteoclasts, and osteoprogenitor cells inter the spaces previously occupied by chondrocytes?

Answer 53

Zone of ossification

Question 54

What is the role of osteoblasts?

Answer 54

Laying down bone onto calcified cartilage spicules

Question 55

What is the role of osteoclasts?

Answer 55

Breaking down and eroding new bone so secondary bone can be formed

Question 56

Does the epiphyseal plate change width through the process of growth?

Answer 56

NO, the epiphyseal plate stays the same width

Question 57

When during the epiphyseal plate development will the bone cells catch up with the chondrocytes?

Answer 57

During the closure of the epiphyseal plate

Question 58

What type of growth is used to grow the bone width wise?

Answer 58

Appositional growth

Question 59

During appositional growth Which should have a higher rate? osteoblasts or osteoclasts?

Answer 59

The rate of osteoblasts should equal the rate of osteoclasts at the end-steal layer

Question 60

What is the process of removing old bone and laying down new bone?

Answer 60

Bone remodeling

Question 61

Bone remodeling occurs where and when?

Answer 61

All over the body all the time

Question 62

What percentage of bone is remodeled every year?

Answer 62

5-10%

Question 63

Negative feedback loops, mechanical stresses, and gravity all play a key role in what process?

Answer 63

Bone remodeling

Question 64

Which two hormones assist in the "When" bone remodeling will occur?

Answer 64

Parathyroid hormone and calcitonin

Question 65

Parathyroid and calcitonin have a direct impact on which molecule?

Answer 65

Ca2+

Question 66

What determines where remodeling will occur?

Answer 66

Mechanical stresses and gravity