TISSUE MECHANICS AND INJURY (L3) Flashcards
known as inert tissue, present in all joints
Connective tissue
all CT has an (blank), composed on cellular, fibrous, and non-fibrous components
extracellular matrix
attracts and binds water, support substance for fibrous and cellular components, contributes to strength of tissue
proteoglycans
Type __ collagen. Thick fibers with very little elongation, resists TENSILE forces
Type 1 collagen
Type __ collagen. Thinner fibers that are less stiff, resist COMPRESSION and SHEAR.
Type 2 collagen
Type __ collagen. Found in skin, more important for healing
Type 3 collagen
Resident vs. circularting cells?
resident cells always present in ECM. circulating cells present only with inflammation or damage.
Ligaments are composed of primary these fibers:
Type 1 collagen arranged in line with the tensile forces… can run in multiple directions however
Tendons are composed primarily of these fibers:
type 1 collagen fibers.
What is the fibrocartilagenous junction?
the area between tendon and bone of gradual change in structure.
4 zones of fibrocartilagenous junction?
- bone
- calcified fibrocartilage
- uncalcified fibrocartilage
- tendon
Whats the difference between the 2 types of cartilage (hyaline and fibrocartilage)?
Hyaline = type 2 collagen, many more proteoglycans, relies on chemical properties and movement of water
Fibrocartilage: type 1 fibers, fewer proteoglycans, relies on nutrients from water
Which collagen type is bone, and what are the two types of bone?
Type 1 collagen, cancellous (spongy) and compact bone (cortical)
region where any slack of the tissue is stretched out before stressing, and where the tissue returns to if the deformation isnt permanent
toe region
region between toe and plastic region where normal deformation occurs
elastic region
where the elastic region meets plastic region, end of the elastic region and where afterwards permanent changes will occur
yield point
region where the tissue deforms permanently
plastic region
the point where, if the load continues through the plastic region, the tissue will fail.
ultimate failure point
the force applied to a cross sectional unit or area
stress
the percentage change in the length or cross sectional area of a material
strain
the continuous change in a tissue’s shape with applied load
creep
more stiffness and more force required to deform tissue at a _____ load vs less stiffness and less force at a _____ load
fast load, slow load
Bone is not compliant (T/F)
true
frequent loading of a bone with low magnitude leads to a
stress fracture
a single load of high enough magnitude to cause a fracture
complete failure
continuous _________ loads modify tendons to resemble cartilage, vs. continuous _________ loads increase tissue size, collagen %, and cross linking of collagen
compressive, tensile
tendons are less resistant to tensile stress than ligaments (T/F)
FALSE - tendons are MORE resistant to tensile stress than ligaments
cartilage resists load in the following process
1) Stress developed in the ECM
2) Swelling pressures developed in interstitial fluid
3) frictional drag resulting from fluid flow throughout the ECM
Group from smallest to largest: fascicle, myofilament, myofibril
myofilament, myofibril, fascicle
Describe the four phases of the cross bridge cycle:
- Coupling: calcium released, binds to troponin, troponin moves away from myosin binding site
- Contraction: myosin heads bind to the site with ADP (lose a phosphate, get a contraction)
- Uncoupling: the loss of phosphate opens up a site for the ATP to bind
the rigid, most stable position of the joint. The greatest protection of the joint.
closed packed position
the more open space that is any other position other than closed packed
open packed position
a specific loose packed position with the most minimal congruency between surfaces, greatest laxity in capsule and ligament
resting position
constant length phenonmenon
the limitation of movement at one joint is dependent on the position at which another joint is held.
