Connective Tissue and Cartilage Flashcards
What is mesenchymal?
- Embryonic CT
- Few fibers, star shaped cells, pluripotent
- Derived from Mesoderm (minus head/neck)
What are the proteins which compose the extra cellular matrix?
- Collagen
- Elastin
- Fibrillin
- Laminin
- Fibronectin
What are the main components of Connective Tissue?
- Ground substance
- Fibers (Collagen Reticular, Elastic)
- CT cells (fibroblasts, Adipose)
- Wandering Cells (Mo, Plasma, Mast, WBC)
- Lymphatics and nerves
How is glycine related to structure of collagen?
Glycine is found every 3rd position of the polypeptide chain of the helix
Describe the components and appearance of Type I Collagen.
- Large fibers formed from Type I
- Easily seen, acidophilic bundles
- Forms tendons and ligaments
Describe components and H&E appearance of reticular fibers?
- Delicate thin fibers made of Type III collagen cross-linked to form a mesh
- Visible with only special silver stains
- Basement membrane and highly specialized lymph tissue
Describe components and H&E appearance of Elastic fibers?
- Thin branching fibers made of elastin with micro-fibrillar proteins
- Not visible unless in large amounts; special stains usually needed
What are the types of Collagen, and what are they associated with?
Type I: Flexible and strong —> Ben, fibrocartilage, teeth stuff
Type II: Resist pressure; Hyaline/elastic cartilage
Type III: Reticular fibers; All CT, Blood vessels, nerves, Smooth muscle, stroma
Type IV: Organized into meshwork to provide support and attachment to underlying CT; Basal lamina
What is Fibrillin?
Large glycoproteins
Secreted by EC fibroblasts in areas such as fibres of lens, periosteum, arterial Wall.
Mutation in Fibrillin gene —> Morgan’s Syndrome
Describe Marian syndrome
- Mutation in Fibrillin gene
- Autosomal dominant
- Symptoms: Ectopis lentos, Abnormalityes in skeleton, and aortic aneurysm
What is the structure and function of Laminin?
- Cross-shaped glycoproteins
- Collagen IV, Heparin, heparin sulfate
Function:
- Cell surface receptor
- Cell adhesion
- Cell differentiation
- Anchoring glycoproteins to basal Lamina
What are GAGs?
- Linear polysaccharides
- Cmposed Of Uronic acid and a hexosamine
- Linear chains are bound to protein core
What is Wharton’s Jelly?
Gelatinous loose CT found in umbilical cord
What are the different Macrophage types in specialized tissue
Lungs - Dust Cells
Liver - Kupfer cells
What are the histological features of plasma cells?
- Basophilic Cytoplsm/RER
- Eccentric Nuclei w/ heterochromatic “clock-face” nucleus
What are histological features of Mast cells?
- Large amoeboid motile cells
- metachromatic secretory granules which obscure the nucleus
What is Ehlers-Danilo’s Syndrome?
- Deficiency of collagen-processing enzymes
- Hypermobility of joints
- Stretchy skin
- Fragile skin
- Vascular defects
What is Osteogenesis imperfecta?
Brittle bone disease
- Grafile bones which break easily
- Mutation in Type I Collagen
What is chondrodysplasia?
Abnormal cartilage from mutation in type II Collagen
What is Scurvy?
Ascorbate deficiency leading to Gum/skin bleeding, reduced would healing, unstable triple helix, and increased turnover of cells
What is the role of chondrocytes?
Produce Matrix
What are the three types of Cartilage?
- Hyaline
- Elastic
- Fibrocartilage
Where do the three types of cartilage occur?
Hyaline: Epiphysial growth plate, Ribs, Respiratory tract, Articular cartilage
Elastic Cartilage: Pinna, epiglottis, et=sterna auditory meatus, corniculate, cuneiform Cartilage
Fibrocartilage: Intervertebral discs
What features identify hyaline cartilage?
- Perichondrium present
- Ground substance highly Basophilic and homogenous
- Chondrocytes in lacunae and in groups
What features identify elastic cartilage?
- Perichondrium present
- Numerous Elastic fibers
- SINGLE chondrocytes in lacuna
What identifies Fibrocartilage?
- Perichondrium absent
- Bundles of collagen fibers
- Few chondrocytes seen
Differentiate appositional vs interstitial growth in cartilage.
Appositional:
- Differentiate from cells in Perichondrium
- Adds matrix to outside of cartilage
- Chondroblsts secrete matrix against existing cartilage eventually becoming trapped into the matrix
Interstitial:
- Chondrocytes in lacunae undergo mitosis
- New chondrocytes secrete matrix and separate from each other becoming trapped in own lacunae
- Adds matrix from indies tissue
- isogenous groups
What is achondroplasia?
- Abnormailty of endochondral longitudinal growth resulting in diminished length of tubular bone.
- Membranous bone unaffected
- Extermity involvement is Rhizomelic (proximal) with arms and thighs being severely involved than forearms
- Dorsal kyphosis
- Lumbar lordosis
What is osteoarthritis?
Non-inflammatory degenerative condition of joints characterized by degeneration of Articular cartilage and formation of new bone (osteophytes).
