Connective Tissue Flashcards
(44 cards)
What are the 4 basic types of connective tissue and give examples
Loose - adipose, areolar
Dense/fibrous (proper) - tendon, ligament
Specialised supportive - cartilage, bone
Specialised fluid - blood, lymph
What is connective tissue
Tissue that supports and binds tissues together and is composed of cells in an extracellular matrix
In what forms can ECM exist
As fluid, mineralised or solid
What are the main components of ECM
- collagen
- proteoglycans
- glycosaminogycans
- fluid
What are the components of the ECM
.
What can collagen form?
Collagen can form either
- bones (rigid)
- tendons (flexible)
- cartilage (between the two)
Features of collagen
- main structural protein in ECM
- 28 diff type of collagen
What is the structure of collagen
- trimeric molecule w 3 polypeptide alpha chain wound into helix
- alpha chain is made up of repeated sequence (g-x-y) which creates strength and flexibility
- h atoms fit into the centre of the 3 stranded helix
What is the process of collagen synthesis?
- collagen chains are synthesised as longer precursors called procollagens
- Pro collagen is modified by ER by hydroxyation (addition of an -oh), glycosylation (attachment of sugar molecule) and disulphide bond formation
- procollagen is transported out of the cell through exocytosis
- outside the cell procollagen peptidases removes loose N- and C- terminal ends making molcule less soluble
- results in formation of tropocollagen/collagen (basic building for collagen fibres)
What is the process of collagen assembly?
- tropocollagen self assembles to form individual collagen fibrils (100-300nm)
- at nanoscale, the collagen fibrils have banding patterns alternating dark and light bands, thus pattern arises due to staggered arrangement of tropocollagen
- collagen fibrils are organised side by side in parallel bundles to form collagen fibres (2-10micrometres in diameters)
General features of proteoglycans
- consists of a core protein w/ one or more glycosaminoglycan (GAG) chains
- GAG provides hydration and swelling pressure to the connective tissue so it is able to withstand compressional forces
- proteoglycans are categorised by size and nature of GAGs
- 4 families w/ 40-50 proteoglycans
Features of glycosaminoglycans
- long sugar chains that interact w proteins to maintain tissue structure
- most GAGs are associated with core proteins to form proteoglycans EXCEPT hyaluronan
What is cartilage
Specialised connective tissue w no blood vessels, nerves or lymphatics
What is the makeup o cartilage
Fluid 70-80%
Collagens 15%
Proteoglycans 10%
Other 3%
What does cartilage contain that other connective tissue doesn’t
Chondrcytes
Perichondrium
Wht is chondrocytes
Cells which produce and maintain ECM
- can be isogenous (in clusters) or singe
- they sit within lacunae
- synthesise and degrade ecm
What is perichondrium and what is its main role
A dense sheath covering most cartilage
Main role is to repair cartilage if damaged
What is perichondrium made up of
Outer fibrous (vascular) layer
Inner chondrogenic (cellular) layer
What are the three types of cartilage
Hyaline cartilage
Elastic cartilage
Fibrocartilage
What is structure, function and location of elastic cartilage
What is the structure function and location of fibrocartilage
What is the structure, function and location of hyaline cartilage
- has perichondrium
- has chondrocytes
What is hyaline articular cartilage
What is the collagen arrangement like in hyaline cartilage?
