Lecture 14 Osteogenesis and Joints Flashcards
Mineralization occurs via ____ ions.
Calcium
Give some examples of bones that develop by intramembranous ossification.
Frontal Parietal part of: - occipital - temporal - mandible - maxilla
What 3 things does intramembranous ossification require?
1) well-vascularized primitive connective tissue
2) bone formation is not preceded by the formation of a cartilage
3) an aggregate of mesenchymal cells differentiates directly into osteoid-producing osteoblasts
True or False:
During intramembranous ossification bone formation is not preceded by the formation of a cartilage.
True
To begin intramembranous bone formation, an aggregation of mesenchymal cells differentiate into what type of cell?
osteoblast
Fill in the blank:
Osteoblasts secrete ____, trapping some of the osteoblasts (blastema).
osteoid
During intramembranous bone formation osteoblasts secrete osteoid (which includes type I collagen & non-collagen proteins) which traps the osteoblasts (blastema). The trapped osteoblasts then turn into osteocytes, in which these osteocytes form what?
Osteocytes form a functional syncytium.
What type of bone is formed during intramembranous ossification when numerous trabeculae fuse together?
Spongy Bone
Membrane bone usually consists of two layers of compact bone that enclose a layer of what?
Spongy Bone
During intramembranous ossification, what type of cells line the surface of the bone blastema?
Hint: this cell type is outlining the functional syncytium made by the interconnected cell processes of osteocytes.
Osteoblasts
What cell type initiates the modeling of the primary bone tissue?
osteoclasts
Fill in the Blank:
Although primary bone tissue formation begins as an ______ process, it soon becomes _________ growth.
interstitial process, it soon becomes appositional growth.
At the surface of the osteoid, osteoblasts continue the appositional deposit of matrix. What are the two main components of this matrix?
Type I collagen & Non-collagenous Proteins
True or False:
Calcification is a form of mineralization and is ossification.
False, calcification is a form of mineralization, but is not ossification.
During endochondral bone formation, what is bone replacing?
Cartilage
Where does the primary ossification center occur in the cartilage model?
In the future diaphysis.
During endochondral bone formation the network of cartilage matrix is calcified by the deposition of calcium salts. Is this ossification?
NO, not ossification.
What is happening in the vascular invasion zone?
Osteoblasts begin to deposit osteoid along the calcified cartilage.
The osteoid calcifies.
How do osteoprogenitor cells, (which are derived from the perivascular mesenchyme) reach the primary ossification center and generate osteoblasts?
Vascular invasion zone - thus, osteoprogenitor cells travel into primary ossification center through the blood vessels.
What is happening to the chondrocytes in the hypertrophic zone?
Chondrocytes become hypertrophic as the ossification front approaches.
What is expressed in the proliferative zone?
proliferative chondrocytes start expressing Cbfa 1/Runx2 transcription factors.
What cell type enlarges the bone marrow cavity?
Osteoclasts (osteoclasts “chase”)
What is the definition of a joint?
A joint is where two bones come together.
What are the two types of cartilaginous joints (amphiarthroses)?
1) symphysis
2) synchondrosis
What is a cartilaginous joint?
A joint where bones are joined by hyaline or fibrocartilage.
What type of cartilage joins a symphysis type cartilaginous joint? Also, give 2 examples of a symphysis type cartilaginous joint.
fibrocartilage - intervertebral discs and pubic symphysis
What type of cartilage joins a synchondrosis type cartilaginous joint? Also, give 2 examples of a synchondroses type cartilaginous joint.
Hyaline cartilage - epiphyseal plates and the first sternocostal joint.
What are the 3 sub-classes of fibrous joints (synarthroses)?
1) suture
2) gomphosis
3) syndesmosis
What type of join is the fibrous joint (synarthroses)?
A join where bones are joined by collagenous and/or elastic fibrous connective tissue.
Give an example of a suture type fibrous joint.
Examples are the joints between the bones of the calvaria.
Give an example of a gomphosis type fibrous joint.
This is a “peg-in-the-socket joint such as the teeth in the alveoli.
Give an example of a syndesmosis type fibrous joint.
Bones are joined by an interosseous fibrous membrane such as the fibrous membrane between the tibia and fibula.
What are the 3 types of synovial joints (diarthroses)?
1) monaxial
2) biaxial
3) triaxial
What is a synovial joint (diarthroses)?
These are the movable joints exemplified by a connective capsule surrounding a fluid-filled joint space.
What are the two functions that ligaments play with a synovial joint?
Ligaments stabilize the capsule and the joint, as well as control and restrict direction and range of motion.
What are the different types of synovial joints based on?
Based on degrees of freedom of movement.
What are two different monaxial types of synovial joints and give an example of each?
Hinge Joint -> humeroulnar and knee joints
Pivot Joints -> atlantoaxial and radioulnar joints
Give 2 examples of a biaxial type synovial joint and examples found in the body.
Condyloid Joint -> metacarpophalangeal and atlantooccipital joints
Saddle (sellaris) Joint -> first carpometacarpal joint
Give an example of a triaxial type synovial joint and where it can be found in the body.
Ball-and-Socket Joint -> glenohumeral and femoroacetabular joints.
In a synovial joint, is the inner synovial portion of the capsule vascularized? Is the outer fibrous portion of the capsule?
Yes, inner synovial portion of capsule is vascularized.
No, outer fibrous portion of capsule is innervated but not vascularized.
True or False:
The synovial membrane has a basal lamina?
False, The synovial membrane does not have a basal lamina.
How many layers of synovial cells make up the synovial membrane?
1-3 layers of synovial cells.
What type of cartilage makes up articular cartilage? Does it have a perichondrium? And is it lined by a synovial membrane?
Hyaline Cartilage
Lacks a perichondrium
Not lined by a synovial membrane
Is the joint capsule of a synovial joint vascularized by dense connective tissue, lined by synovial membrane, and attached to edges of articular cartilage?
Yes, vascularized dense connective tissue
Yes, lined by synovial membrane
Yes, attached to edges of articular cartilage
What hyaluronic acid-protein complex does synovial cells produce?
mucin, which is in synovial fluid.
** mucin produces slick surface that is more slick than ice on ice.
What are the 2 types of synovial cells?
type A -> macrophage-like
type B -> fibroblast-like
