Lecture 14 Osteogenesis and Joints

Question 1

Intramembranous Bone Formation

Answer 1

Review Slides

Question 2

What signals control aggregation of mesenchymal cells?

Answer 2

Wnt, Hedghog, FGF, TGF-beta

Question 3

What is the blastema?

Answer 3

Secreted osteoid with trapped osteoblasts

Question 4

What cells form a functional syncytium?

Answer 4

Osteocytes

Question 5

Osteoid contains what type of collagen and what type of proteins?

Answer 5

Collagen I Non-collagen proteins

Question 6

What type of bone is initial bone?

Answer 6

Woven bone

Question 7

When does bone become lamellar bone?

Answer 7

When the collagen fibers align

Question 8

Lamellae may become symmetrically arranged around a blood vessel forming an _____

Answer 8

osteon or Haversian system

Question 9

Membrane bone usually consists of two layers of _____ bone enclosing a layer of _____ bone

Answer 9

compact, spongy This is called diploe

Question 10

In endochondral bone formation, what happens to the cartilage?

Answer 10

It is REPLACED by bone Review slide 16 for more info on endochondral bone formation

Question 11

Where does endochondral bone formation occur?

Answer 11

Hyaline cartilage model

Question 12

4 zones of endochondral bone formation

Answer 12

Reserve zone Proliferation zone Hypertrophic zone Vascular invasion zone

Question 13

List the steps of Endochondral Bone Formation

Answer 13

See slides

Question 14

What do hypertrophic chondrocytes do?

Answer 14

Form calcifies matrix Synthesize type X collagen Secrete vascular endothelial GF Signal perichondrial cells to become osteoblasts

Question 15

What stimulates proliferation and prevents hypertrophy?

Answer 15

Indian Hedgehog (ihh)

Question 16

Define Joint

Answer 16

Where two bones come together

Question 17

Name the three types of joints

Answer 17

Cartilaginous joints (amphiarthroses) Fibrous joints (synarthroses) Synovial joints (diarthroses)

Question 18

Describe how cartilaginous joints are joined and the two types

Answer 18

Bones are joined by hyaline or fibrocartilage Two types: Symphysis and Synchondrosis

Question 19

Describe Symphysis and give example

Answer 19

Joined by fibrocartilage Example: intervertebral discs and pubic symphysis

Question 20

Describe Synchondrosis and give example

Answer 20

Joined by hyaline cartilage Example: epiphyseal plates and first sternocostal joint

Question 21

Describe how fibrous joints are joined and the three types

Answer 21

Bones are joined by collagenous and/or elastic fibrous CT Types: Suture, Gomphosis, and Syndesmosis

Question 22

Give an example of Suture

Answer 22

Joints between the bones of the calvaria

Question 23

Give an example of Gomphosis

Answer 23

“peg-in-socket” joint such as teeth in the alveoli

Question 24

Give an example of Syndesmosis

Answer 24

Joined by interosseous fibrous membrane such as the fibrous membrane between the tibia and fibula

Question 25

What are synovial joints?

Answer 25

Movable joins exemplified by a connective capsule surrounding a fluid-filled joint space

Question 26

What reinforces synovial joints?

Answer 26

Thickenings of the outer part of the capsule = ligaments

Question 27

What do ligaments stabilize?

Answer 27

The capsule and the joint

Question 28

What is responsible for the control and restriction of direction and range of motion?

Answer 28

Ligaments

Question 29

Joints allowing movement in one plane are said to be:

Answer 29

monaxial

Question 30

Joints allowing movement in two planes are said to be:

Answer 30

biaxial

Question 31

Joints allowing movement in three planes are said to be:

Answer 31

triaxial

Question 32

Examples of monaxial hinge joints

Answer 32

Humeroulnar and Knee Joints

Question 33

Examples of monaxial pivot joints

Answer 33

Atlantoaxial and radioulnar joints

Question 34

Examples of biaxial condyloid joints

Answer 34

Metacarpophalangeal and Atlantooccipital joints Saddle joints

Question 35

Saddle (sellaris) joint

Answer 35

biaxial Exemplified by the first carpometacarpal joint

Question 36

Examples of triaxial joints

Answer 36

Ball and socket joints such as the glenohumeral and the femoroacetabular joints

Question 37

How are ligaments attached?

Answer 37

Sharpey’s fibers

Question 38

What is synovial fluid?

Answer 38

Dialysate located in the synovial cavity

Question 39

Describe the articular cartilage of the synovial joint

Answer 39

Hyaline cartilage Lacks perichondrium Not lined by synovial membrane

Question 40

Describe the joint capsule of the synovial joint

Answer 40

Vascularized dense CT Lined by synovial membrane Attached to edges of articular cartilage

Question 41

Describe the synovial membrane of the synovial joint

Answer 41

Highly vascularized (fenestrated capillaries) 1-3 layers of synovial cells No basal lamina

Question 42

Describe the synovial fluid of the synovial joint

Answer 42

Contains mucin (hyaluronic acid-protein complex) Produced by synovial cells

Question 43

What are the two types of synovial cells?

Answer 43

Type A: macrophage-like Type B: Fibroblast-like

Question 44

Identify the slide and the labeled areas

Answer 44

Fetal Finger

A: Zone of ossification

B: Zone of hypertrophy

C: Zone of calcification