The Tissues of the Human Body: Connective Tissue Flashcards
Features of connective tissues
Unlike epithelia
CT is NOT found on body surfaces
(think of where bones, cartilage, blood is located)
CT can be highly vascular血管的
(Exceptions: cartilage软骨 which is avascular无血管的 and tendons肌腱 with very little blood supply)
Features of connective tissues
Like Epithelia
CT is supplied by nerves
Exception: cartilage
Connective tissue (CT) is composed of
Extracellular matrix细胞外基质 (ECM) and CELLS
Connective Tissue Extracellular Matrix is composed of
Ground Substance (GS)in association with Protein Fibres (3 major types in different proportions
Connective Tissue Extracellular Matrix
The protein fibres of the ECM are secreted by the cells in the ECM.
The structure of the ECM largely dictates the connective tissue qualities.
Connective Tissue Extracellular Matrix
cartilage: ECM is firm and rubbery, but in bone hard and inflexible.
Connective Tissue Extracellular Matrix
Ground Substance
Ground substance is composed of a mixture of :
Water
Proteins (gelatine in jelly!)
Polysaccharides(sugars)
There are 3 different types of connective tissue fibres in the extracellular matrix (ECM):
Collagen fibres(thick)
Reticular fibres
Elastic fibres
Collagen fibres(thick)
1) Very strong but flexible to resist pulling forces
2) Features vary in different tissues e.g. more water around collagen in cartilage than in bone.
3) Collagen 25% of your body and is the most abundant protein!
4) Common in bone, cartilages, tendons and ligaments
5) Parallel bundles
Reticular fibres
1) Composed of collagen with a coating of glycoprotein.
2) Collagen in fine bundles with a coating of glycoprotein(more protein than sugar)
3) Made by fibroblasts
4) Provide strength and support.
5) Form part of the basement membrane
6) Thinner, branching - spreads through tissue.
7) Form networks in vessels and through tissues especially adipose tissue, nerve fibres, smooth muscle tissues
Elastic fibres
1) Thinner than collagen fibres
2) Fibrous network
3) Consist of the protein elastin surrounded by the glycoprotein fibrillin to give more strength and stability.
4) Can be stretched 150% without breaking.
5) Found in skin, blood vessels and lung.
Two Common Connective Tissue Cell Types
Fibroblasts
Adipocytes(fat cells)
Fibroblasts
Location
Widely distributed in connective tissues; migratory
Fibroblasts
Function
Secrete components of the matrix (fibres and ground substance)
Adipocytes(fat cells)
Location
Under the skin and around organs
Adipocytes(fat cells)
Function
Store fat (triglycerides)