MMB (003) Cartilage and Endochondral Ossification Flashcards
Mention type of connective tissue , and it’s components.
Fibroblasts + Collagen
Mention type of connective tissue , and it’s components.
Adipocytes+IC fat
Mention type of connective tissue , and it’s components.
Osteoblasts + osteoid matrix
Mention type of connective tissue , and it’s components.
Chondrocytes + Cartilagenous matrix
…. Is a condition where the tracheal cartilage is soft
Tracheomalacia
Mention complications of tracheomalacia
The trachea partly collapses especially during expiration
• Wheezes or Stridor is the usual symptom, especially during expiration
Is Tracheomalacia congenital or aqquired ?
Can be both ; chronic infection, prolonged intubation
If Tracheomalacia extends to the bronchi it’s called…
Tracheobronchomalacia
Are cartillage cells interconnected ?
No
General Cartilage composition ?
General composition of cartilage ECM ?
… is an example of Glycosaminoglycans , which are chemically composed of …
Hyaluronic acid , Long polysaccharide chains
Describe the structure
The proteoglycans interact with hyaluronic acid to form very large macromolecules which bind large quantities of water by osmotic pressure → stiff gel
This is an Electron micrograph of a ….() aggregate , a component of cartilage
Layers of Hyaline Cartilage ?
1- Perichondrium: 2 layers
2- Chondrocytes
3- Matrix:
The two layers of Perichondrium ?
• Outer fibrous layer: dense fibrous CT containing ,
blood vessels, nerves, lymphatics (Fibroblasts and collagen I)
• Inner chondrogenic layer: contains chondroblasts
Chondroblasts resembles… (cell)
Fibroblasts
Describe the perichondrium’s activity levels
High
Chondroblasts secretes :
Cartillage matrix & collagen II
Chondroblasts diffrentiate into …
Chondrocytes
Define the figure and mention the hidden
Hyaline cartillage
Matrix of hyaline cart. Is composed off …(fibres) :
collagen type II
Function of Outer fibrous layer ,, of perichondrium ??
-Nutrition of cartilage
-Gives muscle attachment
Function of Inner chondrogenic layer ,, of perichondrium ??
growth of cartilage
Fibers composition of Elastic cartilage ?
The regular Collagen II
+
Elastic fibers
Mention the stain used , the tissue and identify the hidden
Does Fibrocartilage contains perichondrium ?
No
Describe the composition of fibrocartillage
Rows of chondrocytes in lacunae,,
separated by parallel bundles of collagen fibres (type I)
Fibrocartillage collagen composition ?
Collagen II + Collagen I
… is the predominant collagen type present in cartilage
(Collagen II) is the predominant collagen type present in cartilage
How is Cartilage norished ?
Nourished by diffusion of nutrients from capillaries in perichondrium or from synovial fluid in joint cavities
2 ways by which a Cartilage can grow ?
Bones can only grow through cartillage by … growth
Appositional
Types of solid joints ?
-Fibrous
-Synchondrosis
-Symphysis
The synovial fluid is a solution of…()
Hyaluronic acid
Structure of Joint Synovium :
-The synovial surface is … (if flattened out the knee synovium would cover 100 m2)
-… layer of cells up to … cells deep
- villous
- discontinous ,, 4 cells
Synovial cells are … in origin.
Mesenchymal
Why are synovial cells not an epithelium ?
-Not connected by junctional complexes
-Do not rest on a basement membrane
How many types of synoviocytes are there ?
Two :
-Type A synoviocytes
-Type B synoviocytes
Define Type A synoviocytes :
-Macrophages containing lysosomal enzymes
Type B synoviocytes secretes…
hyaluronic acid
Normal synovial fluid also contains a small number of…(cells)
leucocytes
Functions of Synovium ?
1) Control of diffusion in and out of joint
2) Ingestion of debris
3) Secretion of hyaluronate, immunoglobulins, and lysosomal enzymes
4) Lubrication of the joint
5) Providing nourishment for the avascular articular cartilage
Structure of Synchondrosis ?
bone-cartilage-bone
Describe amount of movement in Synchondrosis joints
Negligible movement
Mention two examples of Synchondrosis
- The first sternocostal joint
• Epiphyseal growth
• Base of skull until puberty
Define Synostosis
Fusion of two bones
Strucrure of Symphysis ?
bone-cartilage-fibrous tissue-cartilage-bone
Permanent examples of Symphysis ?
pubic symphysis
intervertebral discs
Temporary examples of Symphysis ?
infant mental symphysis
Define the joint
infant mental symphysis
Mineralization of Cartilage Occurs in 3 locations :
1) Junction of articular cartilage and subchondral bone
2) During endochondral ossification
3) In hyaline cartilage as part of the aging process
… is a Mineralization of Cartilage that happens as part of the aging process
In hyaline cartillage
Mention the two types of bone ossification ?
-Intramembranous ossification
- Endochondral ossification
Explain Intramembranous ossification
Direct laying down of bone into the primitive connective tissue (mesenchyme) ,,
without a pre-existing cartilage template
Explain Endochondral ossification
A cartilage is formed as precursor on which new bone is laid down
Sequence of zones in Endochondral Ossification ?
1) Zone of resting (reserve) cartilage.
2) Zone of proliferation: cells divide, form columns; matrix formation
3) Zone of hypertrophy: chondrocytes enlarge; matrix formation
4) Zone of calcification: matrix mineralizing; chondrocytes probably all die (most probably die by apoptosis)
5) Erosion: blood vessels and osteogenic cells invade up lacunar rows
6) Ossification: bone formation on calcified cartilage scaffolding
Mention two bone-related diseases of Vitamin D Deficiency
-Rickets
-Osteomalacia
Pathogenesis of Rickets ?
Defective mineralization or calcification of bones in children ;;
Growth plate widens - cartilage fails to mineralize
Define the abnormality & mention the related disease
Rickets
Osteomalacia pathogensis ?
-Adult disorder (after epiphyseal closure)
-Affects bone only, not the growth plate
-Newly -formed bone matrix fails to mineralise
the proportion of mineralised bone matrix is reduced softening of the bones
Diseases of Cartilage Destruction ?
-Osteoarthritis
-Rheumatoid Arthritis
Most common joint disease?
Osteoarthritis (OA)
Pathogenesis of Osteoarthritis (OA) ?
-Localised condition resulting from trauma, wear and tear; fatigue
-Progressive loss of hyaline cartilage on the articular surface of bones
…. Is a Systemic inflammatory disorder ,, a very severe form of arthritis.
Rheumatoid Arthritis
Pathogenesis of Rheumatoid Arthritis ?
the immune system attacks the joint including the synovial membrane, cartilage, and bone. If left untreated→ cartilage and bone erosion → erosion→ fibrosis and joint deformities
