Cartilage Flashcards
Is cartilage a vascular or avascular tissue?
Avascular
Cartilage has an extensive EM, which cells produce and maintain the EM?
Chondrocytes in the EM
Which feature of the EM of cartilage allows diffusion of substances between chondrocytes and surrounding blood vessels?
The large ratio of GAGs —> hydrated gel —> fast diffusion
What does the ground substance of cartilage consist of? (3)
Proteoglycan monomers
Hyaluronic acid
Collagen fibrils
What sort of molecule is hyaluronic acid?
A GAG
How do the proteoglycan monomers, hyaluronic acid molecules and collagen fibrils in the ground substance of cartilage interact with each other?
Hyaluronic acid attaches to proteoglycan monomers to form a hyaluronate proteoglycan aggregate
These become interwoven with the collagen fibrils
What are some features of the EM in cartilage?
Solid, firm, pliable and resilient to pressure
What characteristic of GAGs allows it to attract water molecules to form a hydrated gel?
High density of -ve charges on the GAG
What is the difference in structure between hyaline and elastic cartilage? What molecules do both contain?
Both contain proteoglycan monomers, GAGs and type 2 collagen
In elastic cartilage there is the addition of many elastic fibres/elastic lamellae
What are the three types of cartilage? Which is the most common?
Hyaline cartilage (most common)
Elastic cartilage
Fibrocartilage
What is the structure of fibrocartilage and hyaline cartilage?
Same structure as hyaline cartilage with the addition of abundant type 1 collagen fibres
What are the only cells found in hyaline cartilage?
Chondrocytes
How do chondrocytes present in hyaline cartilage?
Singly or as small clusters called isogenous groups
Chondrocytes in isogenous groups separate as they…
Lay down the EM
What is the relevance of hyaline cartilage in fetal development?
Hyaline cartilage is the precursor for bones which later develop
Hyaline cartilage is found at the articulating surfaces of which type of bone?
Long bone
Where is hyaline cartilage found in the body?
At articulating surfaces in;
Trachea, bronchi, nose, larynx, parts of the rib cage
What is the perichondrium? Where is it found?
A layer of dense irregular connective tissue
Covers the margin of hyaline cartilage
What cells does the perichondrium contain that are relevant in cartilage?
Elongated fibroblasts
How do the elongated fibroblasts found in the perichondrium develop?
Elongated fibroblasts —-> chondroblasts —> chondrocytes
In what two ways can cartilage grow?
Appositional growth (growth from the sides)
Interstitial growth (deeper chondrocytes divide forming isogenous groups which lay down the EM)
Each chondrocyte lies in a …
Lacuna (space where the cell lies)
What affects how much EM is laid down by chondrocytes?
The response of the chondrocytes to different pressure loads
In what two places is there no perichondrium around the hyaline cartilage?
At articulating surfaces
At epiphyseal growth plates
Does either hyaline cartilage or elastic cartilage calcify with ageing?
Hyaline cartilage does
Elastic cartilage doesn’t
What appearance do elastic fibres take in micrographs?
Dark staining
Name two places in the body where there is elastic cartilage?
External ear (pinna of the ear)
Epiglottis
Eustachian tube
What cells are found in fibrocartilage?
Fibroblasts
Chondrocytes
What does fibrocartilage consist of? What are its properties?
Combination of dense regular CT and hyaline cartilage
Shock-absorbent, resists shearing forces
What appearance do cells in fibrocartilage take?
Cells often seen in rows
Does fibrocartilage have a surrounding perichondrium?
No
Give two examples of where you would find fibrocartilage in the body?
Intervertebral discs
Menisci of the knee joint
Pubic symphysis
