L15- Cartilage Flashcards
The Mesengenic Process
genesis of mesodermal tissues, such as bone, cartilage, muscle, marrow stoma, tendon, fat, dermis, and connective tissues, in either embryos or adult organisms§
mesencyhmals stem cells give rise to
many structures e.g. bone cartilage muscle marrow adipose
which cell forms cartilage
chrondrocytes
types of cartilage (3)
hyaline elastic fibrocarilage
hyaline cartilage is made out of which collagen
type 2 collagen
hyaline cartilage is
dense containing fluid
which GAG aggregates in hyaline cartilage
o Hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres
elastic cartilage found
o Tough but flexible tissue
what forms the basic of elastic cartilage
o Elastic fibres and elastic lamellae (layers)
fibrocartilage (fibrous) contains which type of collagen
type 1 and 2
all types of cartilage haver matrixes containing
proteoglycan and hyaluronic acid.
where is articular cartilage found
between bones
chrondrocytes
a cell which has secreted the matrix of cartilage and become embedded in it.
Proteoglycan structure in cartilage ground substance
- Similar to other connective tissue - 100 hyaluronate proteoglycan aggregates per collagen fibril (only 10 in loose connective tissue) - Makes very stiff gel-like substance
where are chondrocytes found
lying in lacunas (dips)
what do chrondrocytes do
lay down ECM within cell as vesicle - Fibres and GAGs/ hyaluronic acid secreted into spaces between chondrocytes- tissue expansion
during hypertrophy of a chondrocyte the cell grows and grows until it
bursts and releases ECM into the rest of the ECM
what can chondrocytes not do
multiply
cell type in hyaline cartilage
chrondrocytes only when mature - Chondrocytes present singly or in small clusters called isogenous groups (equal origin) - Chondrocytes within isogenous groups separate as they lay down ECM
isogenous groups
Chondrocytes present singly or in small clusters
hyaline and fetal development
hyaline cartilage is the precursor model of those bones that develop by endochondral ossification
as bone develops hyaline caritlage
remains are articular surgaves (between bones) and at the epiphyseal plate
where is hyaline cartilage found
- Knees - Hips - Larynx and trachea - Costal cartilage - Articular tissues of joints e.g. knees
Articular tissues of joints
o Ankle o Knees o Should o Wrist o elbow
what assicts resileince to repeated appliction of pressure in hyaline cartilage
hyaluronic acid- - Matrix is solid and firm but also pliable
are blood vessels found in hyaline cartilage matrix
no- simple diffusion
how can hyaline cartilage grow (2)
apposition growth interstitial growth
perichondrium covers the
margins of hyaline cartilage
appositional grrwth
growths from the periphery
interstitial growths
growth from the centre
perichondrium is what sort of connective tissue
dense connective tissue
outline appositional growth
Grows from the perichondrium (margin of the cartilage) - Grows from precursor cells in to chondroblasts o Chondroblasts grow and grow away from the edge- appositional growth (growth from the periphery)
chondrocytes produce and maintain their own
extracellular matrix
Hyaline Example:
the tracheal wall - Hyaline cartilage forms C shape tracheal cartilages - Cartilage tube reinforces trachea and helps to protect and maintain the airway - Lined with pseudostratified ciliated epithelial
do chondrocytes proliferate ina dults
no- damage is irreversible e.g. rheumatoid arthriitis
cell type in elastic cartilage
only chondrocytes in mature elastic cartilage. Also contains elastic fibres.
where is elastic cartilage found
1) Pinna of the ear 2) Eustachian tube 3) The Epiglottis has great resiliance ot rebound
elastic cartilage grows via
appositional growth
cartilage can also be produced via
Interstitial growth - chondrocytes grow and divide and lay down more matrix inside the existing cartilage.
when does interstitial growth occur
This mainly happens during childhood and adolescence.
in elastic cartilage staining
lots of dark staining due to abundance fo elastic fibres lying in the ECM
cartilage hisotlogy
will look like empty cells the elastic cartilage cells (chondrocytes) do not exist- big holes where cells used to be - Cells have already laid down all fibroelastic cartilage- therefor it apoptosis
elastic cartilage in the ear is produced via which form of growth
interstitial
cells in fibrocartilage
Chondrocytes and fibroblasts - A combination of dense regular connective tissue and hyaline cartilage - Cells distributed in rows (like tendons)
in fibrocartilage there is no
- No surrounding perichondrium
where is fibrocartilage found
- Intervertebral disc- discs between the spine o Impact - Articular dics of the sternoclavicular and temporomandibula joints - The menisci of the knee joints - Pubic symphysis
role of fibrocartilage
Has the resilience to act as a shock absorber and to resist shearing forces
in a histology stain of fibrocartilage
lots of collagen fibres
- Rounded chondrocytes are arranged in rows or as isogenous groups - Relatedly small number of elongated fibroblast
– red arrows point to elongated fibroblast nuclei
chondrocyte will nuclei are
still alive and producing ECM, waiting to burst to lay down more ECM
