Tissue Composition Flashcards
What are the four primary components of tissue?
Collagen, elastin, ground substance, water
About how many type of collagen are there?
At least 15 types
What is unique about the formation of collagen?
Continuous metabolic turnover through growth to maturity
When are collagen fibers more stable?
At maturity
What is the half-life of collagen fibers?
Weeks to months
What type of fiber arrangement is necessary for proper collagen function?
Linear/parallel
What cells are responsible for the production and secretion of collagen molecules?
Fibroblasts
In what location of the cell do the collagen molecules align in a parallel arrangement?
Extracellular matrix
Collagen can stretch up to what percentage of its original length without breaking?
110%
How does a ligament change under tensile forces?
Increase strength and size
What five things are decreased as a result of ligament degeneration?
Fiber diameter Fiber density Fibril number Collagen mass Metabolism
Which type of bone cells have increased activity at the sign of the ligament-bone junction?
Osteoclasts (bone resorption)
Elastin can stretch to what percentage of its original length without breaking?
150%
What is the effect of age on elastic fibers?
Lost resiliency
Fragmentation and fraying
Calcification
Increased number of cross-links
What is another term for ground substance?
“Cement substances”
What are the contents of ground substance?
Glycosaminoglycans (GAGs), plasma proteins, small proteins, and water
What makes up 60-70% of the total connective tissue content of ground substance?
Water
What is the amorphous gel-like substance that surrounds cells?
Ground substance
What is a proteoglycan?
Protein or peptide to which GAGs are covalently attached
What are the four major GAGs?
Hyaluronic acid
Chondroitin-4-sulfate
Chondroitin-6-sulfate
Dermatan sulfate
What is the term for the movement of water to areas of high concentration?
Osmosis
What GAG combined with water makes a powerful lubricant?
Hyaluronic acid
What is the purpose of hyaluronic acid and water lubricating the collagen fibers?
Allow free gliding
Prevent excessive cross-linking
