slides #5 Flashcards
what makes up connective tissue
collagen, elastin, reticulin, ground substance
what determines the mobility of the musculoskeletal system
connective tissue
collagen tissue
high tensil strength
elastin
gives tissue extensibility
reticulin
type III that are only during healing process
ground substance
reduces friction, prevents cross linking, maintains spacing, provides nutrients
areolar tissue
loose, unorganized
skin and fascia
dense tissue
highly organized with short spacing
high tensile strength
ligaments and tendons
how do we lose motion
increase collagen cross linking loss of ground substance fibrosis wound contraction collagen misalignment
immobilized muscle
lactic acid level increases
oxidative capacity decreases because of metabolism
when does atrophy set in
within 2 weeks
what can immobilization cause
reduced protoglycan concentration, matrix organization, necrosis of constant pressure areas, increased fibrofatty issue (scar tissue)
elasticity
stores potential energy
able to stretch and return to previous length
viscoelasticity
loses energy thru heat
fluid like, doesn’t return
plasticity
permenant change
no elastic
over plastic is derformation
force deformation
amount of force needed to maintain change in length or deformation
creep
elongation of tissue when stress is at low level over long period of time
increases with temp increase
creep can cause what
fatigue failure or endurance limit
hookes law
strain of an object is directly related to ability to resist stress
how does collagen fail
force relaxation repsonse doesn’t work
creep too fast
hysteresis
repetitive stretching at a submax load can increase tissue length
viscous properties convert force into heat allowing easier stretching
what principle does pnf use
hysteresis
nuclear bag fiber
2 or 3 nuclei beside each other
more sensitive to velocity of stretch due to increased elasticity
nuclear chain fiber
shorter and thinner
sensitve to stretch only
