Connective Tissue Flashcards
CT proper forms supportive
Stroma or parenchyma
Ground substance
Proteinglycans, glycosaminoglycans, anionic, adhesive glycoproteins
Adhesive glycoproteins found in CT
Laminin and fibronectin
Fixed cells (intrinsic)
Fibroblasts
Fibroblast origin
Hematopoietic cells
Fibroblast fxn
-Synthesize and secrete ECM and produce growth factors
Wandering leukocytes of CT (extrinsic)
- Monocytes: become macrophage when localized in CT
- Plasma cells
- Mast cells
Monocytes
Become macrophages when localized in CT
-AKA histiocytes
Plasma cells differentiate in CT from
B-Lymphocytes
Type III collagen
- Reticular fibers
- Support heavily cellular organs
Reticular fibers stain with
Silver stains and PAS
Reticular fiber location
- Smooth muscle and hematopoietic organs (bone marrow, spleen, lymph nodes)
- Parenchymal organs (liver and endocrine glands)
Elastic Fibers
- Central core of elastin with fibrillin surrounding
- Contain desmosine and isodemosine (aa)
Elastic fibers are rich in which AA
-Glycine and proline
Elastic fiber location
-Vertebral ligaments, larynx, elastic arteries
Fibrillin vs Fibronectin
- Fibronectin has binding sites
- Fibrillin acts as a fibril forming molecule
Type I collagen location
- BONE, dermis, organ capsules, fibrocartilage, cementum
- Osteogenesis imperfecta
Type II collagen
-Hyaline and elastic cartilage
Type III collagen
-Reticular fibers
Type IV collagen
Lamina densa of the basal lamina
Type V collagen
Placenta
Tropocollagen
Formed by the last pro peptide cleavage of pro collagen
Keloid formation
Overproduction of type III collagen
-Leads to elevated scarring in dark skinned patients
Marfan syndrome
Defect in gene coding for fibrillin
Collagen synthesis
- ) preprocollagen in ribosomes on rER
- ) in rER, hydroxylation of proline and lysine (Vit. C dependent)
- ) Glycoslylation of hydroxylysine
- ) triple helix (pro collagen)
- ) trasport to golgi
- ) Release to ECM
- ) in ECM, cleavage of peptides to form tropocollagen
- ) Tropocollagen aggregates to form fibrils
- ) Fibrillar structure is reinforced by enzyme lysyl oxidase (LOX)
Scurvy
- Lack of Vit. C
- Hydroxylation does not occur
- Gum ulceration and hemorrhages
Osteogenesis imperfecta
- single NT change in a gene for collage type I
- Pontaneous fractions, cardiac insufficiency
Ehlers-Danlos IV
- faulty translation of type III collagen
- Aortic and or intestinal rupture
Type III collagen disorders
- Keloid formations (overproduction)
- Ehlers Danlos type IV (underproduction)
Ehlers Danlos VI
- Faulty lysine hydroxylation
- Increased skin elasticity, rupture of eyeball
Ehlers Danlos VII
Decrease in pro collagen peptides
-Increased joint mobility with frequent luxation
Alport Disease
- Defect in type IV collagen
- X-linked
- Blood/protein in urine, progresses to CKD