Lecture 14 cartilage and bone Flashcards
What are the cells that all specialised cells come from called ?
Mesenchymal stem cells
What are the 3 types of cartilage?
Hyaline
Elastic
Fibrocartilage
Give 2 facts that are common to all types of cartilage
All have matrix containing proteoglycans and hyaluronic acid.
All have chondrocytes
What types of cells are in hyaline cartilage?
Chondroytes only
How are cells in hyaline cartilage arranged?
Single or if they’ve recently divided in small clusters called isogrnous groups.
What is the role of hyaline cartilage in fatal development?
Precursor to bones that develope by endochondrsl ossification
Where is hyaline cartilage in adults?
Rib cage Nose Trachea Bronchioles Larynx
What is the role of chondrocytes in hyaline cartilage?
To produce and maintain the extracellualr matrix
Describe extracellualr matrix in hyaline cartilage
Solid and but pilsble as very watery and water is non compressible .
Also contains hysluromic acid which draws water in
How are chondrocytes made?
They are mature specialised cells and so cannot proliferate. Pericondrocytes make chondroblasts which turn into chondrocytes
What are the white sections in this photo
Each chondrocytes lies in a lacuna the white shrinkage ways from the lacuna walls
How do chondrocytes lay down extracellualr matrix
They make many vesicles causing them to grow until they burst releasing content
What are the 2 types of hyaline cartilage growth
Appositional- from one side to the other
Interstitial growth- in both directions
What does hyaline cartilage do in the tracheal esll
Keeps airways open allowing gaseous exchange
What happens if the hyaline cartilage on articular surfaces is damaged
Cannot repair damage as stopped dividing so fibroblasts lay down scar tissue. A loss of mobility and pain occures
What types of cells are in elastic cartilage?
Chondrocytes only (but also elastic fibres)
Where is elastic cartilage found?
External ear, Eustachian tube and epiglottis
How can you I identify elastic cartilage from a photo and what has happened
Cells have no nucleus so white spaces in the middle of cells. This’s because they’ve released elastin fibres into the extracellualr matrix
Where is fibrocartilage found?
Intervertebral discs
Meniscus of knee joint
Pubic symphysis
How are cells arranged in fibrocartilage?
Cells are in rows with no surrounding perichondrium have streaks if collagen and hyaline cartilage
What does fibrocartilage do?
Acts as a shock absorber especially to shearing force
What at the ends of femurs
Growth plates of hyaline cartilage only up to around 24
Where are osteocytes found?
In the middle of bone
What’s the difference between osteoblasts and osteocytes
Osteocytes are where osteoblasts have layers down collagen fibres, these become oestofied and turn into bone trapping the osteoblasts which is now called an osteocytes.
What is bone matrix made up of ?
Inorganic component which resists bending and compression. Organic component (e.g. collagen 1) which resists pulling and tension forces
What’s the difference between rheumatoid and osteoarthritis?
RA- autoimmune disease causing damage to both bone and cartilage and inflammation.
OA- age related narrowing of joint space from wear and tear.
What do osteoblasts do?
Deposit new bone
What are the 4 bone cell types and describeb
Osteoprogenitor- stem cell
Osteoblast- make new bone turn into osteocytes
Osteocytes- terminally differentiated
Osteoclasts- reabsorption of bone
