Lecture 17: Cartilage And Bone Flashcards
What is the composition of cartilage in terms of its cells and extracellular components?
Chondrocytes surrounded by a dense network of collagen and elastic fibres embedded in a gel-like matrix that also contains water and ground substance
What are the 3 components of the cartilage matrix?
Fibres, water and ground substance
What are the 3 types of cartilage?
Hyaline
Elastic
Fibrocartilage
What are the 3 components present in hyaline cartilage matrix?
- Type II collagen
- Hyaluronate proteoglycans aggregates bound to collagen matrix
- Tough dense tissue often containing fluid
How do chondrocytes present in hyaline cartilage?
Present as single cells or if recently divided in small clusters, isogenous groups but separate as they lay down extracellular matrix
What are the 2 components of ground substance?
Hyaluronic acid and proteoglycans
What is the function of chondrocytes?
Produce and maintain the extracellular matrix
Lies in a lacuna
What are the 2 main layers in hyaline cartilage?
Perichondrium and cartilage extracellular matrix with chondrocytes
What is perichondrium?
Dense connective tissue that covers the margin of hyaline cartilage
What does perichondrium contain?
Elongated, fibroblast-like cells that become chondroblasts and then chondrocytes
Why is the cartilage extracellular matrix highly hydrated?
Water is non compressible and so permits resilience to increased pressure
What are 2 examples of hyaline cartilage?
C-shaped tracheal cartilage in tracheal wall Articular surfaces (joints)
What is the function of cartilage in the tracheal wall?
Reinforces trachea and helps to protect and maintain airway
What are the 3 components of the elastic cartilage matrix?
- Elastic Fibres
- Type II collagen
- Hyaluronate proteoglycans aggregates
What are the 3 locations where elastic cartilage can be found?
Pinna of the ear
Eustachian tube (connects ear to mouth)
Epiglottis (flap that ensures food goes to the right tube)
What are the 2 layers in elastic cartilage?
Perichondrium and cartilage itself
What are the 3 main components of fibrocartilage matrix?
A lot of type I collagen
Small amount of type II
Hyaluronate proteoglycan aggregates
How are the cells distributed in fibrocartilage?
Rows
Do fibrocartilage have perichondrium?
No they only have fibroblasts
What are 2 examples of places where fibrocartilage can be found?
Intervertebral discs
Menisci of the knee joint
What is the function of fibrocartilage?
Shock absorber and to resist shearing forces - that’s why it’s quite messy inside - have to resist forces from diff directions
How does cartilage grow?
Appositional growth - growing from the periphery