Musculoskeletal System 1 Flashcards

1
Q

What cells do all bones arrise from?

A

Mesenchymal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 2 types of bone formation?

A

Intramembranous

Endochondral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define intramembranous bone formation

A

Direct conversion of mesenchymal cells into bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of bones undergo intramembranous formation?

A

Flat bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain intramembranous formation

A
  1. Ossification center appears in the fibrous connective tissue membrane
    - Selected centraly located mesenchymal cells cluster and differentiate into osteoblasts, forming an ossification center
  2. Bone matrix (osteoid) is secreted within the fibrous membrane
    - Osteoblasts begin to secret osteoid, which is mineralized within a few days
    - Trapped osteoblasts become osteocytes
  3. Woven bone and periosteum form
    - Accumulating osteoid is laid down between embryonic blood vessels, which form a random network. The result is a network of trabeculae
    - Vascularized mesenchyme condenses on the external face of the woven bone and becomes periosteum
  4. Bone collar of compact bone forms and red marrow appears
    - Trabeculae just deep to the periosteum thicken, forming a woven bone collar that is later replaced with mature lamellar bone
    - Spongy bone, consisting of distinct trabeculae, persists internally and its vascular tissue becomes red marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is responsible for formation of trebeculae?

A

Infiltration of blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What dictates the shape of the skull?

A

Each species has a dictated time for closure of suture and this is what dictates the shape of the skull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define Endochondral ossification

A

Mesenchymal cells first differentiate into cartilage which is later replaced by bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

5 steps of osteogenesis of long bones by enochondral ossification

A
  1. Hyaline cartilage calcifies and periosteal bone collar forms around diaphysis
  2. Primary ossification center forms in the diaphysis
  3. Secondary ossification centers form in epiphyses
  4. Bone replaces cartilage, except the articular cartilage and epiphyseal plates
  5. Epiphyseal plates ossify and form epiphyseal lines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does notochord induce the surrounding mesenchym to secrete

A

epimorphin - attracts sclerotome to migrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do sclerotome cells differentiate into?

A

Chondroblast and chondrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the primarily cranial portion of somite 5?

A

Atlas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the cranial portion, head and tubercle of ribs, derived from?

A

Dense portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the shaft of rib derived from?

A

Diffuse Portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What makes up cartialge matrix?

A

First 9 ribs that go around thorax and meet ventrally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What creates the sternum?

A

Fusion of cartilage matrix at midline

17
Q

What is block vertebrae?

A

Defect in resegmentation

  • typically does not cause any clinical signs
18
Q

What is hemivertebrae?

A

Wedge shaped vertebrae

19
Q

3 defects of hemivertebrae

A

Defect in cartilagenous model

Defect in resegmentation

Defect in calcification

20
Q

What causes the biggest problem in hemivertebrae?

A

Cervical vertebrae

  • wobblers - common in horses and large dogs
21
Q

What is atlantoaxial subluxation?

A

Instability of C1 and C2

22
Q

What causes atlantoaxial subluxation?

A

Defect of resegmentation of C1 and C2

23
Q

What is the dens

A

Protuberance of the axis

24
Q

What is the problem with no dens?

A

Nothing to keep the axis from dislocating

25
Q

What is a hereditary disease in arabian horses?

A

Occipitoatlantoaxial malformation (OAAM)

26
Q

8 points of interest with Occipitoatlantoaxial malformation (OAAM)

A
  1. Malformation in resegmentation
  2. Small foramen magnum
  3. Fusion of C1 to occipital part of skull
  4. Atlantol foramen is smaller
  5. Dens is hypoblastic
  6. Caudal articular surface of atlas resembles the occipital condyle
  7. Axis has broad transverse processes like atlas
  8. Transverse process of C2 are hypoblastic
27
Q

Common problem on hobby farms with ovine>

A

Ovine hereditary chondrodysplasia

  • abnormal cartialge production
  • Chondrocytes are disorderly
  • abnormal endochondral ossification