TOB S6+7 - Cartilage, Bone, Ossification and Bone Disease Flashcards
What is the function of the chondroblasts in cartilage?
Secrete matrix which surrounds and entrapps chondroblasts in ‘lacunae’
What are lacunae entrapped chondroblasts called?
Chondrocytes
What does cartilage contain?
Chondroblasts/cytes
Type 1 collagen
Ground substance
No inorganic substances
What is the composition of the ground substance in cartilage?
Proteins Glycoproteins Glycosaminoglycans (GAGs) Hyaluronic acid Lipids Water
What are the two layers of the perichondrium?
What are these two layers composed of?
What types of cartilage possess a perichondrium?
Outer fibrous layer:
Dense Connective tissue
Inner chondrogenic (cellular) layer: Flattened Fibroblast-like cells that develop into chondrocytes
Perichondrium found surrounding Hyaline and Elastic cartilage
Explain the processes behind the growth of cartilage
Appositional Growth:
Fibroblast-like cells of perichondrium differentiate into chondroblasts which secrete matrix
Interstitial Growth:
Chondrocytes deeper in the cartilage dive forming isogenous groups. They then lay down matrix (this leads to the groups separation).
Describe how Cartilage is important in embryonic development and further growth of a child.
First appears during 5th week of embryo development
Embryo’s skeleton made of hyaline cartilage until replaced with bone.
Remnants of hyaline cartilage persist in growth plates and articular cartilage
What are the three major types of cartilage?
Hyaline cartilage
Elastic cartilage
Fibrocartilage
For hyaline cartilage:
What is the major type of collagen present?
What is its function?
Type 2 collagen present
Provide firm but flexible support
Allow movement of tissues
Where might hyaline cartilage be found?
Respiratory passageway
Articulating surfaces of long bones
Foetal skeleton
For elastic cartilage:
What is the major type of collagen present?
What is its function?
Type 2 collagen present
Provides extra flexibility and support (helps maintain shape) for structures
Where might elastic cartilage be found?
Auditory tubes
Pinna of the ear
Epiglottis
For fibrocartilage:
What is the major type of collagen present?
What is its function?
Type 1 collagen (in thick bundles)
Type 2 collagen as normal
Support and rigidity
Resistant to stretching and compression,
Can be weight bearing
Acts as a shock absorber and resists tearing
Where might fibrocartilage be found?
Intervertebral disks
Menisci
Pubic symphysis
Portions of the tendons
Describe the staining properties of cartilage matrix
Territorial matrix surrounding chondrocytes/isogenous groups stains more deeply with haemotoxylin than the inter-territorial matrix further from the chondrocytes
This is due to territorial matrix being more highly sulphated
What types of cartilage are avascular and how do they obtain nutrients?
Hyaline cartilage, elastic cartilage and fibrocartilage
Obtain nutrients via diffusion
What kind of joint is Fibrocartilage associated with?
Any joint where durability, resistance to compression and strength is needed
Why is elastic cartilage so named?
Matrix contains a large amount of elastic fibres
What is the clinical relevance of hyaline cartilage?
Hint: Ageing
Susceptible to degenerative aging process, can calcify/ossify in old age and disease
Joint pain can be the result of degraded articular cartilage erosion (osteoarthritis) or destruction of articular cartilage by granulating synovial membrane tissue (rheumatoid arthritis)
What is the clinical significance of fibrocartilage?
Tearing of menisci can occur
Rupture of annuls fibrosus (invertebral disk capsule)
Can lead to a slipped disk.
Does Elastic cartilage calcify in old age?
Nope
Bone is an example of what type of tissue?
Connective tissue
List the characteristics of bone
Hint: Nutrient supply? Composition? Physical characteristics? Types?
Can withstand compression, stress and deformation
Nutrient supplied through blood and lymph vessels
Innervated, susceptible to pain, particularly periosteum
Contains cells, fibres and ground substance like any other connective tissue
Two types:
Cancellous bone surrounded by compact/cortical bone
List the functions of bone
Support
Protection
Mineral storage
Haemopoesis