Tissues 3 Flashcards
What does extracellular matrix surround?
Connective tissue
What is extracellular matrix.
Complex network of proteins and carbohydrates
What are the functions of the ECM?
- Physical Support
- Determines mechanical and physiochemical properties
- Influences growth, adhesion and differentiation status
- Essential for development, tissue function and organogenesis.
What are the components of connective tissues?
- Collagens
- Glycoproteins
- Proteoglycans
(cellular component)
Types I-III collagen are?
Fibrillar
Type 4 collagen is present where?
In the basement membrane (basal lamina)
Give examples of glycoproteins.
- Fibronectin
- Fibrinogen
- Laminins (in basement membrane)
Give examples of proteoglycans.
- Aggrecan
- Versican
- Decorin
- Perlecan (in basement membrane)
How can matrix proteins be affected?
Gene mutations
Name 5 diseases arising from matrix proteins being affected.
- Osteogenesis imperfecta - Type 1 Collagen
- Marfan’s Syndrome - Fibrillin 1
- Alport’s syndrome - Type IV collagen (a5)
- Epidermolysis bulls - Laminin 5
- Congenital Muscular Dystrophy - Laminan 2 (a2)
Diseases arising from ECM metabolism being affected?
Hurler’s Syndrome - L-a-iduronidase
Other micopolysaccharidioses
What causes fibrotic disorders?
Excess ECM deposition
Name some fibrotic disorders.
Liver fibrosis - cirrhosis
Kidney fibrosis - diabetic nephropathy
Lung fibrosis - silicosis
Disorders due to excessive loss of ECM?
Osteoarthritis
What are collagens?
Family of fibrous proteins - found in all multicellular organisms
Major proteins of bone, tendon and skin
What is the most abundant protein in mammals?
Collagen
How are collagen fibrils arranges in skin?
Why?
Successive layers are perpendicular to each other (same as in bone and cornea).
Resists force in all directions. Gives tissues tensile stress.
How many known types of collagen are there?
28
How many alpha chains comprise a collagen?
- Forms a triple helix
How many genes form Type 1 Collagen?
2 genes
Which types of collagen are homotrimeric?
Type 2 and 3
They have the same a chain
How many genes code for collagen?
42.
Every 3rd amino acid residue in the a chain is?
A glycine.
Why does the glycine face the interior of the polypeptide chain?
It is hydrophobic.
Smallest amino acid so can fit in the gap