Connective Tissue Flashcards
What makes up the extracellular matrix?
Made of collagen fibers and ground substance. The collagen fibers were the most abundant protein in the body, made up of 7 alpha chains, those chains come together to make a triple strand helical structure. Some amino acids part of the collagen fibers were: glycine (because small, rather than large amino acid that would disrupt), proline, hydroxyproline, hydroxylysine. The glycosylation of the alpha peptides with glycosaminoglycans make up the ground substance.
What are clinical uses of collagen?
wound healing, tissue regeneration, and treatment of osteoarthritis
Steps of collagen synthesis:
mRNA is translated to preprocollagen, signal peptide removed, hydroxylations of proline/lysine from vitamin C, glycosylation of alpha peptides make procollagen, and modifications in the Golgi form tropocollagen which are the fibrils.
What are types of collagen and their pathologies (except type 6) ?
Type 1 = bone, tendon; osteogenesis imperfecta - fragile bone, sclerosis - increased collagen in certain parts of skin or around organs, scurvy - periodontal ligament weakens, and teeth fall out.
Type 2 = hyaline and elastic cartilage; hypochondrogenesis - cartilage is scaffold for long bone, so malformation of ribs and extremities
Type 3 = reticular fibers; Ehlers Danlos Type 4 - effects the skin and causes easy bruising
Type 4 = basal lamina; Alport syndrome - dense collagen where we want thin collagen, ex. ears, kidneys, eyes
Type 5 = amnion/ chorion in fetus + dermal/epidermal junction; Ehlers Danlos Type 1 - very elastic skin because separation of dermis from epidermis
Type 6 = anchors basal lamina to stroma (tissues)
Type 7 = above dermis/ basal membrane; epidermolysis- fragile skin; blisters off
What are 2 types of elastic fibers?
- Elastin - coiled; stretch of arteries
2. Fibrillin - linkers for stretch; associated with Marfan Syndrome (Abraham Lincoln lol)
What are functions of CT?
Support, packaging material, nutrition, resist/exert force, storage, and defense
What are the CT propers vs CT specialized?
Proper are dense irregular/regular tissue, loose (areolar) connective tissue, elastic (laminae) connective tissue, and reticular CT. The CT specialized are adipose, hematopoietic/blood, lymphatic, embryonal, elastic fibers, and mucous.
What are a few types of gylcosaminoglycans found in ground substance?
hyaluronic acid - hydrophilic; chondroitin 4/6 sulfate - shock absorbers
What disorder is caused by build up of glycosaminoglycans?
Hurler’s, where lysosomes can’t break down GAGs.
What are the importance of glycoproteins and proteoglycans?
Both provide structure. Proteoglycan has glycosaminoglycans covalently attached forming some of the ground substance; this can be found in all connective tissue and ECM. The structure of a glycoprotein has a heparin binding site which laminin binds (which anchors plasma and basement membranes) to and fibronectin (attachment of cells in CT) binding sites.
What are the cells of the connective tissue (6)?
- Fibroblasts - spindle shaped cells with oval nuclei; produce components of ECM
- Myofibroblasts - fibroblasts that have contractile ability; involved in contraction of wound healing.
- Macrophages - they’re phagocytic and can be specialized; they also have extra hepatic production of bile and can break down fats
- Mast cell - oval nuclei; release histamines causing allergic responses
- Leukocytes/ white blood cells - lymphocytes/eosinophils (bilobed nuclei)
- Mesenchymal cells - pluripotent cell; involved in development
What’s difference between brown and white adipose?
Brown has numerous droplets (less present in body); functions as heat source by preventing proton in ETC for ATP production. White adipose is one lipid droplet and is for energy storage.
What are characteristics of embryonal connective tissue?
Lots of active fibroblasts, the CT covers the 2 arteries and one vein of umbilical cord surrounded by warten’s jelly, which is ECM with scattered collagen and ground substance.
What are characteristics of loose areolar CT?
participates in inflammation of abdomen, has lots of cells like macrophages/mast cells, and is made up of collagen bundles with some elastic fibers.
What are characteristics of dense irregular collagen?
found in joint capsules/ GI, and dermis, less cells, and inactive fibroblasts.
Loose areolar CT
