Exam 3: Osteogenesis and Joints Flashcards
Trace the steps of intramembranous bone formation:
- Aggregation of mesenchymal cells
- Wnt, hedghog, FGF, TGF-B signals
- Mesenchymal Cells→ Osteoblasts
- Osteoblasts secrete osteoid, trapping some osteoblasts= Blastema
- Trapped Osteoblasts → Osteocytes
- osteocytes form a functional syncytium
- Mineralization occurs via calcium ions
- osteoblasts form a epithelial like covering over surface of primary bone tissue & can secrete more osteoid (collagen I and Non-collagen Proteins)
- Primary ossification center becomes a trabecula
- Numerous trabeculae fuse together to form spongy bone
- Inital bone, woven bone (random callagen fibers)
- Collagen fibers align= bone becomes lamellar
- Lamellae may become symmetrically arrange around a blood vessel for an osteon (haversian system)
- Membrane bone usually consists of two layers of compact bone closing a layer of spongy bone
- https://www.youtube.com/watch?v=Vwethc4jt7U
Identify the tissue sample below
Cancellous Bone
Identify the tissue sample below
Cancellous Bone
Identify the tissue below
Cancellous bone
T/f bone cartilage is converted to bone in the process of Endochondral bone Formation.
False, cartilage is REPLACED by bone
Trace the steps of Endochondral Bone development!
- Primary ossification center occurs in future diaphysis of cartilage model.
- Chondrocytes become hypertrophic
- Chondrocytes secrete vascular endothelial growth factor
- Blood vessels break through perichondrium, bringing in osteoprogenitor cells
- Hypertrophic cartilage cells undergo apoptosis, leaving behind thin strands of calcified matrix
- Ostoeblasts use calcified strands as substrates for deposition of osteiod
- Osteoid is calcified.
- Simultaneously, cells derived from inital perichondrium begin to secrete osteoid appositionally
- Perichondrium now= periosteum
- secondary ossification centers occur in the epiphyses
- Epiphyses and diaphyses are separated initally by epiphyseal plate (growth plate)
- Reserve Zone
- Porliferative Zone
- Hypertrophic Zone
- Vascular Invasion Zone
What is a joint?
Where two bones come together
Name the two ways cartilaginous joints (amphiarthroses) are joined
Hyaline or Fibrocarilage
How are symphysis joints joined? What type of joint does this form?
- Symphyses are joined by fibrocartilage
- samples include intervertebral discs and the pubic symphysis
Forms a cartilaginous joint
What are joints in synchondrosis joined by? What type of joint is it?
- synchondroses are joined by hyaline cartilage
- examples include epiphyseal plates and the first sternocostal join.
this is a cartilaginous joint.
How are fribrous joints (synarthroses) joined?
They are joined by colagenous and/or elastic fibrous CT.
Where is a suture joint found and what type of joint is it?
examples include joints between the bone of the calvaria. This is a Fibrous joint
Where is a Gomphosis joint found and what type of joint is it?
This is a Ped-in-th-socket joint such as the teeth in the alveoli. This is a Fibrous joint
How is a Syndesmosis joint joined? Where is it found? What type of join is it?
Bones are joined by an interosseous fibrous membrane. An example is the fibrous membrane between the tibia and fibula. This is a FIBROUS joint.
What are the characteristics of Synovial Joints (diarthroses)?
- moveable joints exemplified by a connective capsule surrounding a fluid-filled joint space
- Synovial joints are often reinforced by thikening of the outer part of the capsule referred to as ligaments
- Liagments stabilize the capsule and the joint
- Ligaments control and restrict direction and range of motion.
What are the synovial joints that allow for movement in only one plane (monaxial)?
- Hinge Joints: humeroulnar and knee joints
- Pivot joints: atlantoaxial and radioulnar joints
what are teh synovial joints that allow movement in two planes (biaxial)?
- Condyloid joints: metacarpophalangeal and atlantooccipital joints
- Saddle (sellaris) joint: exemplified by the first carpometacarpal joint
Joints allowing movement in three planes (triaxial)?
- Ball-and-socket joints such as the glenohumeral and the femoroacetabular joints.
what is the histology of synovial joint articular cartilage?
- Hyaline cartilage
- Lacks perichondrium
- Not lined by synovial membrane
what is the histology of synovial joint, Joint capsule?
- Vascularized dense CT
- Lined by synovial membrane
- Attached to edges of articular cartilage
what is the histology of synovial joint, synovial membrane?
- Highly vascularized (fenestrated Capillaries)
- 1-3 Layers of synovial Cells
- No basal Lamina
what is the histology of synovial joint, synovial fluid?
- Contains mucin (hyaluronic acid-protein complex)
- Produced by synovial cells
what is the histology of synovial joint, Synovial cells types?
- Type A
- Macrophage-like
- Type B
- Fibroblast-like
What is the tissue below? Identifly the labeled structures.
Epiphyseal Plate
A: Proliferative Zone
B: Hypertrophic zone
C: Calcification of territorial Matrix.
