Lecture 3; Connective tissue Flashcards
Function of connective tissue
- binds, supports and strengthens other body tissues
- a major transport system of the body (blood)
- a major site of stored energy reserves (adipose)
features of connective t
unlike epithelium; not found on body surfaces, CT is highly vascular. Like epithelium, CT has nerves (except cartilage)
what is CT compose off?
ECM and cells
what ECM composed off?
Ground substance and protein fibres
what is ground substance made out off?
water, protein and polysaccharides (including GAGs)
Describe proteoglycans
Made up of proteins and GAGs
describe glucosaminoglycans (gags)
- otherwise called mucus polysaccharides
- long, unbranched polysaccharides
- repeating disaccharide unit
(ie. an amino sugar and a uronic sugar)
what is the repeating unit of hyaluronic acid?
amino sugar - N acetyl glucosamine
uronic sugar- glucuronic acid
Give examples of glucoaminoglycans
Sulfated GAGs- dermatan sulphate, keratan sulphate, heparin and chondroitin sulphate. these bind to proteins to form proteoglycans
Non-sulfated GAGs- hyaluronic acid (not covalently bound to a core protein)
What is the function of GAGs?
collectively they trap water making the substance jelly like
application of hyaluronic acid
viscous slippery substance that binds cells together, lubricates joints and maintains shape of eyeball
Application of chondroitin sulphate
support and provide adhesive features of cartilage, bone, skin, blood vessels
application of Keratan sulphate
found in bone, cartilage and cornea of the eye
Application of dermatan sulphate
found in skin, tendons, blood vessels, heart valves
What is hyaluronidase?
produced by WBC, sperm and some bacteria. Makes ground substance more liquid so that they can move more easily in it and makes access to the egg easier for the sperm
Describe exopthalmos
periorbital ECM deposition and thyroid disease
-most common in younger women, associated with goitre, autoimmune over-activation of thyroid (goitre), autoimmune action of fibroblasts in ECM of the eye.The deposition of GAGs and the influx of water increase periorbital contents
What are the 3 types of fibres in CT?
produced by the cells of the CT; collagen, reticular and elastic fibres
describe collagen fibres
very strong and flexible to resist pulling forces; features vary in different tissues (ie. more water around collagen in cartilage than bone); most abundant protein of your body (25%); common in bone, cartilages, tendons and ligaments; occur in parallel bindles
Reticular fibres description
composed of collagen with a coating of glycoproteins; collagen in fne bundles (with glycoprotein coating); made by fibroblasts; strength and support; are part of BM; thinner, branching and spread through the tissue; form networks in vessels through tissue, especially adipose tissue, nerve fibres, smooth muscle tissue
Elastic fibres description
thinner than collagen fibres; fibrous network; consists of the protein elastin surrounded by glycoprotein fibrillin to give strength and stability; can be stretched up to 150%; found in skin, blood vessels and lungs
Marfan syndrome
hereditary defect in elastic fibres usually the result of a dominant mutation that codes for fibrillin; TGFb is a growth factor produced by the body and doesn’t bind to fibrillin to keep it inactive
individuals usually tall and long limbed; have a chest deformity; normal lifespan but needs medical vigilance; may have weakened heart valves and arterial walls; 1 in 20,000 live births
Fibroblasts location and function
one of 2 most common CT cells
location: widely distributed in CT; is migratory cells
Function: secrete components of the matrix (fibres and ground substance)
Adipocytes location and function
second most common cell in CT
Location: under the skin and around organs
Function: stores fat
macrophages (histiocytes) location and function
Location: phagocytic cells; fixed and wandering forms of CT.
Function: fixed cells in CT (dust cells-lungs; kupffer cells-liver; Langerhans cells-skin)
Wandering in CT (sites of infection/inflammation/injury)
