9. Cartilage and bone Flashcards
Where is cartilage found?
Between joints
Which cell gives rise to all the specialised connective tissues?
Mesenchymal stem cell
What are the 3 types of cartilage
Hyaline cartilage
Elastic cartilage
Fibrocartilage
What do all the cartilage types have?
All have matrix containing proteoglycan and hyaluronic acid
All have chondrocytes
All the cartilages contain a lot of fluid
In hyaline cartilage, what does the matrix contain?
Matrix contains type II collagen. The hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres – dense tissue often containing fluid.
Which cells are present on hyaline cartilage?
Only chrondocytes
How are chrondocytes formed?
Grows from perichondrial cells - cells on the edge- fibroblast like precursors. As they develop, they develop into chrondoblasts. They divide and produce chrondocytes which makes up the matrix.
Which are the only cells that can divide in cartilage tissue?
Chrondoblasts
How are chrondocytes present?
Chondrocytes are present singly or, if recently divided in small clusters called isogenous groups
What happens to the chrondocytes in isogenous groups as they lay down extracellular matrix?
The chondrocytes within the isogenous groups separate as they lay down extracellular matrix
Why is hyaline cartilage needed for bones?
- In early fetal development hyaline cartilage is the precursor model of those bones that develop by endochondral ossification
- As long bones develop, some hyaline cartilage remains at the articulating surface, (and also at the epiphyseal plate until bone growth ceases) - parts of the rib cage, nose, and in the trachea, bronchi and larynx
What is the function of chrondocytes?
They produce and maintain the extracellular matrix
What does each chrondocytes lie in?
A lacuna
How do the chrondocytes produce the extracellular matrix?
Chrondocytes grow until they burst and release their content containing fibres and GAGs/hyaluronic acid into the extracellular matrix
What is the function of hyaluronic acid?
Hyaluronic acid assists resilience to the repeated application of pressure
What are not present in cartilage?
Blood vessels - matrix allows diffusion of material from other tissue
What is the Proteoglycan structure in cartilage ground substance?
- Have lots of collagen
- Have About 100 hyaluronate proteoglycan aggregates per collagen fibril
- Makes a very stiff gel-like substance
Where in the body is hyaline cartilage found?
- Cartilages in nose
- Articulate cartilage of a joint
- Costal cartilage
- Larynx
- Trachea
- Lung
What is appositional growth?
Growth of hyaline cartilage from the periphery
What is interstitial growth?
Growth of the hyaline cartilage from the centre
What is perichondrium?
the dense connective tissue that envelops cartilage where it is not at a joint.
What does the perichondrium contain?
Contains elongate, fibroblast-like cells that can develop into chondroblasts and then into chondrocytes
The hyaline cartilage extracellular matrix is highly hydrated, what is the advantage of this?
Water is non-compressible and so permits resilience to increased loads
Describe the structure of the tracheal wall which contains hyaline cartilage
- Tube formed by C-shaped tracheal cartilages (HYALINE CARTILAGE)
- Cartilage in tube reinforces trachea and helps to protect and maintain the airway
- Lined with pseudostratified ciliated epithelium
What does the matrix of elastic cartilage contain?
Matrix contains many elastic fibres and elastic lamellae (layers) – tough but flexible tissue.
What cells do elastic cartilage contain?
Only chrondocytes
Where is elastic cartilage found?
Only found in 3 places in the body:
• The pinna of the ear (and the external part of the acoustic meatus)
• the Eustachian tube
• the epiglottis
Describe the layers found in the pinna of the ear from the muscle to the epidermis
Muscle Adipose tissue - white coloured Elastic cartilage Fibrocollagenous tissue Dermis Epidermis
What does the matrix of fibrocartilage contain?
Matrix contains lots of type I collagen fibres
What cells are present in fibrocartilage?
Chondrocytes and fibroblasts
What is fibrocartilage a combination of?
Fibrocartilage is a combination of dense regular connective tissue and hyaline cartilage
How are the cells in fibrocartilage often distributed?
The cells are often seen to be distributed in rows
Does fibrocartilage contain perichondrium?
There is no surrounding perichondrium
Where is fibrocartilage present?
Present in intervertebral discs, articular discs of the sternoclavicular and temporomandibular joints, the
menisci of the knee joint and in the pubic symphysis