| Question |
Answer |
| True or False: Collagen is the most abundant protein in the body? |
True. (25% of all protein in the human body is collagen) |
| Collagen types and their primary locations |
Be (So Totally) Cool, Read Books 1. (90% of all collagen) Bone, Skin, Tendon (bONE) 2. Cartilage (carTWOlage) 3. (Reticulin)-blood vessels 4. Basement membrane |
| Collagen Type I locations |
Be (So Totally) cool, read books -Bone (bONE) -Skin -Tendon -dentin -fascia -cornea -late wound repair |
| Collagen Type II locations |
be (so totally) COOL, read books -Cartilage (carTWOlage) -vitreous body -nucleus pulposus |
| Collagen Type III locations |
be (so totally) cool, READ books (Reticulin) -blood vessels -skin -uterus -fetal tissue -granulation tissue |
| Collagen Type IV locations |
be (so totally) cool, read BOOKS -basement membrane or basal lamina (four under the floor) |
| Collagen synthesis: list of events and locations |
Intracellular 1. Synthesis (Rough Endoplasmic Reticulum) 2. Hydroxylation (Endoplasmic Reticulum) 3. Glycosylation (Golgi) 4. Exocytosis Extracellular 5. Proteolytic processing 6. Cross-linking |
| Collagen production step 1: Synthesis |
-In rough endoplasmic reticulum -translation of collagen alpha chains (aka preprocollagen) |
| Composition and other name of collagen alpha-chains |
-Gly-X-Y (where X and Y are proline, hydroxyproline, or hydroxylysine) -aka preprocollagen |
| Composition and other name of preprocollagen |
-Gly-X-Y (where X and Y are proline, hydroxyproline, or hydroxylysine) -aka collagen alpha-chains |
| Collagen production step 2: Hydroxylation |
-In endoplasmic reticulum -Hydroxylation of specific proline and lysine residues (using vitamin C) |
| Collagen production step for which vitamin C is required |
Hydroxylation of Gly-X-Y chains to form hydroxyproline or hydroxylysine |
| Collagen production step 3: Glycosylation |
-In Golgi apparatus -Glycosylation of preprocollagen lysine residues and formation of procollagen (triple helix of three collagen alpha chains) |
| Composition of procollagen |
Triple helix of three collagen alpha chains (aka three preprocollagen chains) |
| Osteogenesis Imperfecta: Pathophysiology |
Cannot take glycosylated alpha-chains and form procollagen (triple helix) |
| Collagen production step 4: Exocytosis |
Exocytosis of procollagen |
| Collagen production step 5: Proteolytic processing |
Cleavage of terminal regions of procollagen, transforming it into insoluble tropocollagen |
| Composition of tropocollagen |
Procollagen (triple-helix) with terminal regions cleaved |
| Collagen production step 6: Cross-linking |
Reinforcement of many staggered tropocollagen molecules by covalent lysine-hydroxylysine cross-linkage to make collagen fibrils |
| Enzyme which performs collagen cross-linking (final step) |
Lysyl oxidase |
| Ehlers-Danlos syndrome: Pathophysiology |
Nonfunctioning lysyl oxidase resulting in lack of collagen fibrils (linked tropocollagen molecules) |
| Ehlers-Danlos syndrome: Presentation |
-Hyperextensible skin -Tendency to bleed/easy bruising -Hypermobile joints |
| Ehlers-Danlos syndrome: |
of types |
| Ehlers-Danlos syndrome: Inheritance |
Varies |
| Ehlers-Danlos syndrome: Most frequently affected collagen type and result |
Type III collagen resulting in blood vessel instability |
| Osteogenesis Imperfecta: Types |
-Abnormal collagen type I (bONE) --Most common --Autosomal-dominant -Type II --Fatal in utero or neonatal period |
| Osteogenesis Imperfecta: Presentation |
1. Brittle bone disease: Multiple fractures with minimal trauma (often during birth) 2. Blue sclearae (due to translucency of connective tissue over the choroid) 3. Hearing loss (abnormal middle ear bones) 4. Dental imperfections due to lack of d |
| Multiple fractures in a child: Differential Diagnosis |
-Child abuse -Osteogenesis Imperfecta |
| Osteogenesis Imperfecta: Incidence |
1:10,000 |
| Immunohistochemical stain for: Connective tissue |
Vimentin |
| Immunohistochemical stain for: Muscle |
Desmin |
| Immunohistochemical stain for: Epithelial cells |
Cytokeratin |
| Immunohistochemical stain for: Neuroglia |
GFAP (Glial fibrillary acid proteins) |
| Immunohistochemical stain for: Neurons |
Neurofilaments |
| Vimentin stains for: |
Connective tissue |
| Desmin stains for: |
Muscle |
| Cytokeratin stains for: |
Epithelial cells |
| GFAP (Glial fibrillary acid proteins) stains for: |
Neuroglia |
| Neurofilaments stain for: |
Neurons |
| Elastin: Description and Location |
Stretchy protein within lungs, large arteries, elastic ligaments |
| Elastin and Collagen: Peptide composition difference |
Both: Proline and lysine rich Collagen: Hydroxylated forms Elastin: Non-hydroxylated forms |
| Elastin: Structure |
Tropoelastin with fibrillin scaffolding (fibrillin defect in Marfan's syndrome) |
| Elastin: Conformations |
Relaxed and stretched |
| Elastase: function |
Break down elastin |
| Elastase inhibitor |
alpha-1-antitrypsin |
| Elastase excess: Found where |
Found in emphysema |
| Association of emphysema with elastase |
Excess elastase activity can cause emphysema |
| Apoptosis: Characteristics |
1. Cell shrinkage 2. Chromatin condensation 3. Membrane blebbing 4. Formation of apoptotic bodies which are then phagocytosed |
| Apoptosis: Events which initiate it |
-Embryogenesis -Hormone induction (menstruation) -Immune cell-mediated death -Injurious stimuli (eg radiation, hypoxia) -Atrophy |
| Necrosis: Definition |
Enzymatic degradation of a cell resulting from exogenous injury |
| Necrosis: Characteristics |
1. Enzymatic digestion 2. Protein denaturation 3. Release of intracellular components 4. Inflammatory process. |
| Necrosis: Types and where they are found |
1. Coagulative (heart, liver, kidney) 2. Liquefactive (brain) 3. Caseous (Tuberculosis) 4. Fat (Pancreas) 5. Fibrinoid (blood vessels) 6. Gangrenous (limbs, GI tract) |
| Reversible or irreversible cell injury: Cellular swelling |
Reversible |
| Reversible or irreversible cell injury: Nuclear chromatin clumping |
Reversible |
| Reversible or irreversible cell injury: Decreased ATP synthesis |
Reversible |
| Reversible or irreversible cell injury: Ribosomal detachment |
Reversible |
| Reversible or irreversible cell injury: Glycogen depletion |
Reversible |
| Reversible or irreversible cell injury: Plasma membrane damage |
Irreversible |
| Reversible or irreversible cell injury: Lysosomal rupture |
Irreversible |
| Reversible or irreversible cell injury: Calcium influx leading to oxidative phosphorylation |
Irreversible |
| Reversible or irreversible cell injury: Nuclear pyknosis |
Irreversible |
| Reversible or irreversible cell injury: Karyolysis |
Irreversible |
| Reversible or irreversible cell injury: Karyorrhexis |
Irreversible |
| Reversible or irreversible cell injury: Mitochondrial permeability |
Irreversible |
