Flashcards in Bone Growth Deck (17):
Differentiation of chondroctues occurs within mesenchymal model.
What do these chondrocytes produce?
Where does this first occur?
What does this lead to?
Chondrocytes produce cartilage
First occuring in the diaphyseal region of humerus and femur
Ultimately the long bones are composed principally of cartilage
Where does the primary ossification centre form?
In the diaphysis
What does the primary ossification centre do?
Hypertrophy of the chondrocytes
Invasion by blood vessels
-Forming nutrient artery system
Conversion to bone starts circumferentially from the periosteum
Where are the secondary ossification centres?
At the epiphyseal regions
The process of enchondral ossification in secondary ossification centres occurs via what?
What are the two types of ossification?
What are the differences?
-Formation of bone within hyaline cartilage
-Bone forms directly from mesenchymal tissue and does not require a prior cartilage model
-No growth plates
-Occurs in flat bones including the skull bones, clavicle and scapula
What are the ossification centres of the elbow?
When do they each form?
C = Capitellum (2y)
R = Radial head (4y)
I = Internal Epicondyle (6y)
T = Trochlea (8y)
O = Olecranon (10y)
E= External epicondyle (12y)
Give 2 types of physis (growth plate)
Horizontal (producing longitudinal growth)
Spherical (producing circumferential growth)
How are chondrocytes arranged in the physis?
Chondrocytes arranged in layers
Each layer having a different function and destiny
What are the 3 layers of the growth plate?
Name the sub layers
-Zone of reserve
-Zone of proliferation
-Zone of hypertrophy
Describe the zone of reserve
(Cells, function etc)
Spherical chondrocytes that are few in number with a large extra-cellular matrix
High concentrations of lipids, glycogen and proteoglycan's for storage
Bone matrix production
What does dwarfism/gigantism effect?
Action of GH which mostly effects zone of proliferation
Proportionate changes in size
Mucopolysaccharidosis is a deficiency in which enzyme?
What are the 4 syndrome types in mucopolysaccharidosis?
What does mucopolysaccardisosis cause?
Complex sugars found in urine
Abnormality in Zone of Hypertrophy
What is effected in bone by Rickets?
Gross distortion of Zone of maturation
Poorly defined zone of Provisional Calcification
Physeal "cupping" and widening ("champagne glass")
Bowing of long bones "swiss cheese trabeculae" etc