Connective Tissue 2 Flashcards
Define connective tissue?
tissue that connects, supports, binds or seperates other tissues and organs
Where do connective tissue originate from?
embryonic mesenchyme - tissue developing mainly from the mesoderm
Define CT properties that distinguish it from other primary tissues?
- originates from the mesenchyme 2. different degrees of vascularity/blood flow 3. mostly composed of non-living material
CT consists of?
cells + extracellular matrix
Extracellular matrix consists of?
protein fibres + ground substance
What is ground substance?
a complex of anionic, hydrophilic proteoglycans, GAGs, Multi-adhesive glycoproteins
Name cells of the CT?
- fibroblasts + fibrocytes 2. adipocytes 3. macrophages 4. mast cells 5. plasma cells 6. other leukocytes
Describe structure and function of fibroblasts + fibrocytes?
- most common cell type in CT with mesenchymal origin 2. produce and maintain most of the extracellular components
Describe structure and function of adipocytes?
- mesenchymal origin 2. specialized for cytoplasmic storage of lipids
Describe structure and function of macrophages?
- bone marrow derived - part of mononuclear phagocyte system 2. phagocytosis of extracellular matrix components and debris
Describe structure and function of mast cells?
- contain secretory granules 2. release of many bioactive substances e.g. histamine
Describe structure and function of plasma cells?
- B-lymphocyte derived 2. synthesis of antibodies
Describe structure and function of other leukocytes?
form a population of wandering cells in CT
Name the fibres of CT?
- collagen 2. reticular 3. elastic
Describe collagen fibres?
- made of collagen 2. key element of all CT + epithelial basement membranes + external laminae of muscle and nerve cells 2. is strong and resistant to normal shearing + tearing forces
Describe reticular fibres?
- made mainly of collagen III 2. forms extensive network of thin fibres that support most cells e.g. reticular lamina of basement membrane
Describe elastic fibres?
- made of elastin 2. allows tissues to be stretched or distended and return to their original shape
What is ground substance?
highly hydrated transparent complex mixture of glycosaminoglycans + proteoglycans + multi adhesive glycoproteins
3 classes of macromolecules in ground substance?
glycosmaminoglycans + proteoglycans + glycoproteins
Function of ground substance?
fills the space between cells and fibers in connective tissue acting as a lubricant and a barrier to the penetration of invaders because of its viscous state
What are the types of CT?
- connective tissue proper 2. embryonic connective tissue 3. specialized connective tissue
How is CT proper classified?
amount of collagen fibres present
What are the types of CT proper?
- loose or areolar CT 2. dense irregular CT 3. dense regular CT
Describe loose/areolar CT?
- structure: well vascularized + consists of thin and looslely arranged collagen and elastic fibres + has abundant cells of various types and abundant ground substance 2. function: Support microvasculature, nerves, and immune defense cells 3. location: lamina propria, mesentry, subcutaneous tissue, omentum
Describe irregular CT?
- structure: few cells (typically fibroblasts) + little ground substance + abundant collagen fibres interweaving in various directions 2. function: protects and supports organs - resists tearing 3. location: found in regions under considerable mechanical stress + where protection is given to ensheathed organs e.g. dermis, submucosa of GIT, organ capsules (testes, periosteum + perichondrium)
Describe dense regular CT?
- structure: closely packed collagen bundles arranged according to a definite pattern + little ground substance + few fribroblasts that are aligned in parallel to fibres 2. Adapted to resist prolonged or repeated stresses exerted in the one direction + Provide strong connections within musculoskeletal system; strong resistance to force 3. location: ligaments, tendons
Difference between dense irregular and dense regular CT?
dense irregular CT has collagen in various direction and has less collagen and dense regular CT has collagen in a parallel structure and has more collagen
Name types of embryonic connective tissue?
- mesenchyme 2. mucoid CT
Name specialized connective tissue?
- reticular CT 2. adipose CT 3. bone, cartilage and blood
Name specialized tissues?
- elastic 2. reticular 3. mucoid 4. adipose
Describe elastic tissue?
specialized dense CT formed by elastic fibres - appears yellow in color
Describe reticular tissue?
loose CT made up of reticular fibres - forms supporting networks for cells
Describe mucoid tissue?
has abundant jelly-like ground substance rich in hyaluronan, sparse fibroblasts & collagen - embryonic type of CT found mainly in umbilical cord & fetal organs
Describe adipose tissue?
aggregation of fat cells - found subcutaneously in most parts of the body
What are the functions of CT?
- holds together structures e.g. skin, muscles, blood vessels 2. forms a framework that supports the cellular elements of organs e.g. spleen 3. provides a tight covering for deeper structures + maintains shape 4. store of nutrition - adipose tissue 5. helps the body fight against invading foreign substance - cells of the immune system 6. laying down collagen fibres for wound repair + regenration - fibroblasts
