TISSUE MECHANICS AND INJURY (L3)

Question 1

known as inert tissue, present in all joints

Answer 1

Connective tissue

Question 2

all CT has an (blank), composed on cellular, fibrous, and non-fibrous components

Answer 2

extracellular matrix

Question 3

attracts and binds water, support substance for fibrous and cellular components, contributes to strength of tissue

Answer 3

proteoglycans

Question 4

Type __ collagen. Thick fibers with very little elongation, resists TENSILE forces

Answer 4

Type 1 collagen

Question 5

Type __ collagen. Thinner fibers that are less stiff, resist COMPRESSION and SHEAR.

Answer 5

Type 2 collagen

Question 6

Type __ collagen. Found in skin, more important for healing

Answer 6

Type 3 collagen

Question 7

Resident vs. circularting cells?

Answer 7

resident cells always present in ECM. circulating cells present only with inflammation or damage.

Question 8

Ligaments are composed of primary these fibers:

Answer 8

Type 1 collagen arranged in line with the tensile forces… can run in multiple directions however

Question 9

Tendons are composed primarily of these fibers:

Answer 9

type 1 collagen fibers.

Question 10

What is the fibrocartilagenous junction?

Answer 10

the area between tendon and bone of gradual change in structure.

Question 11

4 zones of fibrocartilagenous junction?

Answer 11

1. bone
2. calcified fibrocartilage
3. uncalcified fibrocartilage
4. tendon

Question 12

Whats the difference between the 2 types of cartilage (hyaline and fibrocartilage)?

Answer 12

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

Question 13

Which collagen type is bone, and what are the two types of bone?

Answer 13

Type 1 collagen, cancellous (spongy) and compact bone (cortical)

Question 14

region where any slack of the tissue is stretched out before stressing, and where the tissue returns to if the deformation isnt permanent

Answer 14

toe region

Question 15

region between toe and plastic region where normal deformation occurs

Answer 15

elastic region

Question 16

where the elastic region meets plastic region, end of the elastic region and where afterwards permanent changes will occur

Answer 16

yield point

Question 17

region where the tissue deforms permanently

Answer 17

plastic region

Question 18

the point where, if the load continues through the plastic region, the tissue will fail.

Answer 18

ultimate failure point

Question 19

the force applied to a cross sectional unit or area

Answer 19

stress

Question 20

the percentage change in the length or cross sectional area of a material

Answer 20

strain

Question 21

the continuous change in a tissue’s shape with applied load

Answer 21

creep

Question 22

more stiffness and more force required to deform tissue at a _____ load vs less stiffness and less force at a _____ load

Answer 22

fast load, slow load

Question 23

Bone is not compliant (T/F)

Answer 23

true

Question 24

frequent loading of a bone with low magnitude leads to a

Answer 24

stress fracture

Question 25

a single load of high enough magnitude to cause a fracture

Answer 25

complete failure

Question 26

continuous _________ loads modify tendons to resemble cartilage, vs. continuous _________ loads increase tissue size, collagen %, and cross linking of collagen

Answer 26

compressive, tensile

Question 27

tendons are less resistant to tensile stress than ligaments (T/F)

Answer 27

FALSE - tendons are MORE resistant to tensile stress than ligaments

Question 28

cartilage resists load in the following process

Answer 28

1) Stress developed in the ECM
2) Swelling pressures developed in interstitial fluid
3) frictional drag resulting from fluid flow throughout the ECM

Question 29

Group from smallest to largest: fascicle, myofilament, myofibril

Answer 29

myofilament, myofibril, fascicle

Question 30

Describe the four phases of the cross bridge cycle:

Answer 30

1. Coupling: calcium released, binds to troponin, troponin moves away from myosin binding site
2. Contraction: myosin heads bind to the site with ADP (lose a phosphate, get a contraction)
3. Uncoupling: the loss of phosphate opens up a site for the ATP to bind

Question 31

the rigid, most stable position of the joint. The greatest protection of the joint.

Answer 31

closed packed position

Question 32

the more open space that is any other position other than closed packed

Answer 32

open packed position

Question 33

a specific loose packed position with the most minimal congruency between surfaces, greatest laxity in capsule and ligament

Answer 33

resting position

Question 34

constant length phenonmenon

Answer 34

the limitation of movement at one joint is dependent on the position at which another joint is held.