Connective Tissue Proper

Question 1

Cell types of CT proper

Answer 1

fibrocyte

fibroblast

Question 2

CT Proper fibers

Answer 2

collagen, elastic and reticular fibers

Question 3

CT proper matrix

Answer 3

Ground substance (PGs, GAGs)
Tissue fluid

Question 4

Fibrocyte

Answer 4

Quiescent cell, low activity for maintaining fibers and ground substance of ECM
Stimulated to become active (fibroblast) upon injury or tissue damage (for wound healing)

Question 5

Fibroblasts

Answer 5

Intense synthetic activity for collagen and ground substance molecules

Cytoplasm

• large amounts of ER
• well developed Golgis

Question 6

ECM Molecules

Answer 6

Collagen-main fiber; resists tensile force to provide strength to tissue
Elastin-provide resiliency allows stretching
Proteoglycans-filamentous protein core with attached GAGs; provide framework
Glycoproteins-PRO bound to small CHO molecues provides framework for ECM

Question 7

Collagen is what percent of dry weight

Answer 7

30%

Question 8

Four groups of collagen

Answer 8

collagen that forms fibrils
fibril-associated collagen
collagen that forms anchoring fibrils
collagen that forms networks

Question 9

Type 1: fibroblast/osteoblast

Answer 9

Bone tendon ligaments= resist tension

Question 10

Type 2: chondroblast

Answer 10

cartilage= resist compressive forces, shear forces at surface

Question 11

Type 3: fibroblast

Answer 11

pliable tissues; blood vessels, uterus, GI tract, skin, muscle=structural maintenance in expandable organs; initial collagen of wound repair

Question 12

Type 4: fibroblast

Answer 12

basement membranes; muscle cells, epithelial cells, adipoctyes=support of delicate structures; filtration

Question 13

Tropocollagen

Answer 13

protein unit that polymerizes to form collagen fibrils

differences in the chemical structure of these polypeptide chains are responsible for the various types of collagen

Question 14

Collagen fibrils

Answer 14

thin, elongated structures

several micrometers long (type 2)

Question 15

Collagen fibers

Answer 15

fibrils aggregate to form fibers (types 1 and 3)

Question 16

collagen bundles

Answer 16

collection of collagen fibers (type 1)

Type 2=no fibers/bundles
Type 4=no fibrils or fibers

Question 17

Ehlers-Danlos Type VII

Answer 17

decrease in procollagen peptidase activity

increased articular mobility; frequent sublux

Question 18

Scurvy

Answer 18

lack of Vit. C (no procollagen formed) Ulceration of gums; hemorrhages; weak bones

Question 19

Osteogenesis imperfecta

Answer 19

Change of one nucleotide in genes for collagen Type I
Spontaneous fractures;
Cardiac insufficiency

Question 20

Keloid scarring

Answer 20

Hyper-production of collagen

Local swelling that forms in scars of the skin

Question 21

Elastic Fibers AAs

Answer 21

Amino acids: Desmosine and Isodesmosine provide covalent bonds that form cross-links between elastin fibers

5x more extensible than rubber

Question 22

Elastic fibers

Answer 22

synthesized by: fibroblast; smooth muscle cells
Located: pliable tissue i.e. blood vessels, uterus, etc.
main fxn: elongation w/o deformation

Question 23

With advanced age:

Answer 23

Elastic fibers are replaced by Type I collagen; tissues lose elasticity (more easily deformed)

Question 24

Marfan Syndrome

Answer 24

Genetic mutation; disrupts proper elastic fiber synthesis

Tissues rich in elastic fibers are most affected
(i.e. large/medium-sized arteries contain large amounts of elastin)

Creates non-compliant (brittle) tissue, especially arteries, that are prone to rupture

Question 25

Ground substance fxn

Answer 25

Fills spaces between cells and fibers of CT and provides a pathway for waste and nutrient exchange Fluid provides for lubrication of ECM Provides a barrier to penetration of foreign (infectious) agents

Question 26

Tendons Fxn

Answer 26

Function Connect muscle to bone Transmit mechanical force generated by muscle to bone to create joint movement

Question 27

Tendons Innervation

Answer 27

``` Innervation Golgi Tendon Organ (GTO) Pain fibers (free nerve endings) ```

Question 28

Tendons nutrient supply

Answer 28

Nutrient supply Limited vascular supply Synovial membrane (tendon sheath)

Question 29

Synovial sheath layers

Answer 29

dense irregular CT Visceral layer Parietal layer b/w the layers is a cavity for fluid provides lubrication for tendons to slide w/in their fibrous sheath

Question 30

Ligament Functions

Answer 30

Connects bone to bone Controls and guides normal movement of joints Limits excess motion Contain more elastic vs. tendons

Question 31

Ligament Innervation

Answer 31

Proprioceptive fibers | Free nerve endings (pain)

Question 32

Ligament nutrient supply

Answer 32

Limited vasculature

Question 33

Loose CT proper with aging

Answer 33

decreased elasticity decreased hydrophilic capabilities decreased ROM increased work to overcome inelasticity

Question 34

Dense Irregular CT proper with aging

Answer 34

decreased elasticity decreased hydrophilic capabilities decreased ROM increased work to overcome inelasticity

Question 35

Dense Regular CT proper with aging

Answer 35

``` decreased in size decreased protein synthesis decreased tensile force decreased load to failure fiber degradation ```

Question 36

Imobilization changes in CT proper

Answer 36

generates contracture

Question 37

Tendons and ligaments immobilized

Answer 37

decrease tensile force generation decreased load to failure decreased GAGs/H20 Increased cross-linking of collagen: makes them less flexible Synovial sheath becomes adherent to tendons--preventing full ROM

Question 38

CT proper changes with acute activity

Answer 38

``` increased temperature and increased elasticity micro tears (that are repaired): create stronger and larger ligament/tendon prevention of cross links to maintain extensibility ```

Question 39

CT proper changes with chronic activity

Answer 39

Hypertrophy of ligament/tendon – allows the CT to transmit (accept) increased amounts of force ↑ deposition of type I collagen, ↑ load to failure ↑ ROM if stretched