Connective Tissue, Muscle Tissue (load deformation/stress strain)

Question 1

Type I Collagen

Answer 1

thick, stiff, binding; found in ligaments, fibrous joint capsules, tendons; very orderly arrangement;

Question 2

Type II Collagen

Answer 2

thin, lower tensile strength, provides framework for other structures/provides internal strengtn; found in hyaline cartilage; disorganized structure resisting stresses from all different directions

Question 3

Elastin

Answer 3

small fibrils, resists tension, has elastic properties; found in hyaline cartilage and ligamentum flavum; in between collagen type 1 and 2 in size;

resists tension and returns to original shape

Question 4

Ground Substance

Answer 4

made up of GAGs, solutes, and water

Question 5

GAGs

Answer 5

proteoglycans; have negative charge

repel each other to increase volume in tissues and hydrophilic to increase water content in tissue;

contributes to mechanical properties

Question 6

Water in Ground Substance

Answer 6

allows for diffusion of nutrients; provides mechanical properties

Question 7

Cells in CT

Answer 7

synthesize ground substance, tissue maintenance and repair, constant turnover; does not influence mechanical properties

Question 8

Fibroblasts

Answer 8

create cells in dense CT; in ligaments, tendons, supportive CTs

Question 9

Chondrocytes

Answer 9

creates cells in cartilage; in hyaline articular cartilage and fibrocartilage

Question 10

Dense CT: Composition

Answer 10

high type I collagen fibers, low elastin and low fibroblasts; ligaments, tendons, capsules

Question 11

Dense CT: Characteristics

Answer 11

Poor healing (low vasculature), adapts to stress/strain with increased stiffness (increased collagen and GAG synthesis)

Question 12

Irregular Dense CT

Answer 12

creates joint capsule; collagen arranged irregularly in ground substance to resist tensile forces from multiple directions

Question 13

Regular Dense CT

Answer 13

ligaments and tendons; orderly/parallel to resist tension in longitudinal direction and to transmit large forces from muscle to bone; also scar tissue

Question 14

Load Deformation Curve

Answer 14

apply a load in one direction, measure deformation; elastic region, plastic region, yield point, ultimate failure

Question 15

Elastic Region

Answer 15

linear portion of the curve; tissue can go back to its resting length; as load increases, deformation increases linearly

Question 16

Plastic Region

Answer 16

we start to get change in the tissue and it won’t go back to its original length; we can predict what length it does go back to, which is different than its original length

Question 17

Yield Point

Answer 17

the point where it goes from elastic region to plastic region

Question 18

Ultimate Failure Point

Answer 18

where the tissues ultimately break

Question 19

Stress Strain Curve

Answer 19

very similar to load deformation curve, but converting to normalized units to compare between materials

Question 20

Stress

Answer 20

force/area; F/A

could also be measured in pascals (N/m2)

Question 21

Strain

Answer 21

change in length/ initial length; a percentage

Question 22

Stiffness

Answer 22

slope of the elastic region; young’s modulus of elasticity

stress over strain

Question 23

Energy

Answer 23

energy stored in tissue; can vary depending on when you release the tissue

Question 24

Viscoelastic Creep

Answer 24

deformation response occurs when exposed to a constant load (stress); rapid initial deformation followed by slow deformation (creep) until equilibrium is reached

Question 25

Toe Region

Answer 25

nonlinear portion prior to the linear elastic region; collagen fibers not parallel here, so the region where collagen fibers start to straighten

Question 26

Viscoelasticity

Answer 26

rate dependent! If tissue loads rapidly, there is a stiffer response than if the tissue was loaded slowly; think silly putty

Question 27

Plastic Changes in Tissue

Answer 27

plastic changes to CT are thought to be brought about by slow, low-intensity, and long-duration stretches; causes a change in structure and gets us into the plastic region to change tissue; creep! if too fast, there will be a stiffer response

Question 28

Stress-Relaxation

Answer 28

rapid high initial stress followed by a slow decreasing stress required to maintain the deformation; distributes the stress across the tissue; protective; stress attenuates across all tissues