Connective Tissue- Week 8 Flashcards
Explain roles of connective tissue.
it encompasses all organs & body cavities which can connect one part with another but also can act as a separator
Name ECM components
-Collagen
-Elastic Fibres
- Ground substance
- Adhesion proteins
-Basal laminae (basement membrane)
Describe structures and functions of collagen fibres in ECM
Structure: long stiff triple stranded helixes made up of 3 a-chains
Functions: intermolecular crosslinks- fibre formation- form meshes which can be regular(give strength in specific direction where collagen ends on lining) or disorganised (gives less strength but will have strength in more directions)
what does ECM stand for
Extra-Cellular Matrix
Describe structures and functions of Elastic fibres in ECM
- Structure: formed from elastin(monomer), get cross-linking between monomers= stretchy fibre
- Function: enables organs to stretch & return to original shape
Describe structures and functions of Ground Substance in ECM
-Structure: comprised of: Glycosaminoglycan chains(repeating chains of disaccharides/sugars gives rigidity and fills space), proteoglycans (protein core which is glycosylated- lost of carbohydrates are attached to it)
Function: mechanically supportive gel, which allows diffusion of nutrients
Describe structures and functions of Adhesion proteins in ECM
-Structure: has fibronectin-plays a big part in adhesion, growth.
-Function: link components of ECM together- link cells to ECM
Describe structures and functions of Basement membrane in ECM
- Structure: flexible, tough, thin sheet of matrix molecules- primary structure made up by lamin and collagen IV
-Function: selective barrier to cells-semipermeable filter, support and scaffold for regeneration
Name key cells in connective tissue
- Adipocytes: store fat (White – few large fat droplets
▪ Brown – many smaller fat droplets, multiple mitochondria) - Immune cells: Macrophages
▪ White blood cells
▪ Patrol & remove micro-organisms
Compare loose and dense connective tissue – structure & function.
FUNCTION: loose tissue- Attachment(skin to underlying tissue)
▪ Fills void around organs (Cushioning & protection)
▪ Supports & surrounds blood vessels
▪ Diffusion – nutrients, O2
Dense tissue- Attach bone to bone & muscle to bone
▪ Stabilise the joint
STRUCTURE: loose tissue:
▪ Fibres run in all directions – loose network (collagen predominant fibre and elastic fibres-less predominant)
▪ Ground substance-to fill gaps
▪ Fibroblasts – lay down fibres
Dense tissue-
*Abundant fibres & fewer cells(i.e. blood vessels) vs loose
▪ Fibres in dense network (parallel or irregular)- only strong in in which the fibres are running
▪ Little ground substance- as there’s no space
* contain fibroblast
Describe and detail the roles of the various types specialised connective tissue
-cartilage: the ability to resist compressive forces, enhance bone resilience, and provide support on bony areas where there is a need for flexibility
-BONE: Growth & remodelling
▪ Osteoid – predominantly type I cartilage
▪ Bone – mineralised calcified, Ca3
(PO4)2, type I cartilage
-ADIPOSE:
▪ Protection
▪ Insulation
▪ Nutrient storage
what are the 2 proteins that cartilage is made out of
▪ Collagen (mainly type II) – mechanical stability
▪ GAGs – compressive forces
Explain the role of chondrocytes, osteoblasts & osteoclasts in bone development
-chondrocytes produces the cartilage matrix and as they become surrounded by this matrix they differentiate into Chondrocytes.
-osteoblasts are found on the surface of growing bone- they secrete matrix components, & over time once they become enclosed in bone they will differentiate into Osteoclasts.
-Osteoclasts- maintain bone, will preform local absorption and secretion
what are the 3 types of cartilage & what are its functions and where are they found in the body
- Fibrocartilage – resists compression & tension
-Hyaline cartilage – flexible & resilient
-Elastic cartilage – highly bendable
what type of collagen makes up fibrocartilage and where’s it found
Type I & II collagen
(found in Vertebral disks, tendon attachments to bones & junctions between flat bones and pelvis)