Exam 1: Tissue Mechanics Flashcards
Primary tissue components
Collagen
Elastin
Ground substance
Water
Collagen has continuous _____ through growth to maturity
Metabolic turnover
At maturity the collagen fibers become more
Stable
Collagen chains are synthesized ans secreted by
Fibroblasts
Collagen molecules align in the ____ in a ____ arrangement
Extracellular matrix; parallel
Collagen can stretch to ____ its original length
110%
Ligaments change under tension
Inc ligament strength
Inc ligament size
Increased lig size is accomplished by
Inc # of collagen fibrils
Inc collagen fibril diameter
Inc cross-linking
Inc collagen fibril packing density
Immobilization causes these degenerative ligament (collagen) changes
Dec diameter Dec density Dec fibril # Dec overall mass Dec metabolism
Immobilization at ligament-bone junction changes
Inc osteoclast activity
Bone resorption
Disruption of diffusion
Immobilization increases the risk of ____ at the ligament-bone junction
Avulsion injuries
Elastin can stretch to ____ its original length
150%
Age-related changes to elastin
Lose resiliency
Fragmentation/fraying
Calcification
Inc cross-links
Contents of Ground Substance
GAGs
Plasma proteins
Small proteins
Water
GAGs, plasma proteins and small proteins all attract
Water
Water = _____% of total CT content
60-70%
4 major GAGs
Hyaluronic acid
Chondroitin-4-sulfate
Chondroitin-6-sulfate
Dermatan sulfate
_____ is found in high concentration within GAGs
Glucosamine
Hyaluronic acid + water is a powerful _____
Lubricant
Water maintains _____ between collagen fibers which allows ____ and prevents _____
Critical distance
Allows free gliding; prevents excessive cross-linking
Mechanical forces play an important role in ______ of tissue as well as ______
Development, maintenance, remodeling
Damage and disease
Tissue biomechanics is study of how different parts of human body _____
React to external forces
When a load produces forces that push material together
Compression
When a structure is stretched longitudinally
Tension
Forces acting parallel to each other in opposite directions
Shear
Forces twisting/rotating in opposite directions about long axis
Torsion
Combination of tensile and compressive loads
Bending
Behavior of compressed structures depends on
Its length; how far or long load is applied
Nearly constant compressive forces are transmitted to
Vertebral body and IVD
Examples of compression injuries
Bruises
Crushing
Compression fractures
Pinching
Compression fractures happen a lot in _____ because there is _____
Older female patients
Too much force/too little bone density
Tension is a _____ force
Stretching or pulling
Tension elements of the body are ___
Soft tissues
Tensile forces occur in the IVD during ____ movements
Rotational
Examples of tension injuries
Sprain/strain
Avulsion fractures
Nerve traction injuries
_____ bones are most at risk for fracture due to shear forces
Cancellous
In the spine ____ resist shear forces
Facet joints and annulus fibrosus fibers
Examples of shear injuries
Brain injuries
ACL/PCL injuries
Blisters
Spine injuries