Exam 1: Ch 4

Question 1

proliferation

Answer 1

increase in cell number by mitotic division

endothelial cells & fibroblasts proliferate during tissue repair

driven by growth factos

Question 2

differentiation

Answer 2

when stem cells specialize in structure & function

multiple orderly steps driven by expression of a tissue-specific set of genes

Question 3

many tissues retain ______ cells that are….

Answer 3

progenitor cells

able to replace cells for that tissue only

Question 4

interphase

Answer 4

G1: RNA & protein synthesis

S: DNA replication

G2: protein synthesis

Question 5

mitosis

Answer 5

2 cells form from 1

Question 6

cell cycle checkpoints

Answer 6

allow opportunity for repair

no progression from G1 –> S if DNA is damaged

no progression from G2 —> M if DNA wasn’t duplicated

Question 7

cell cycle regulation

Answer 7

cyclins control cell cycle by activating protein kinases (CDK)

CDKs phosphorylate target proteins to activate them

causes progression through cell cycle

progression through specific checkpoints controlled by specific cyclins

Question 8

proliferative capacity

Answer 8

labile cells like intestinal endothelium cycle continuously

other cells become stable and stop cycling

Question 9

stable cells and G0

Answer 9

stop cycling = G0

stable cells can re-enter cycle with proper stimulation

some stable cells stop cycling permanently – nerve, skeletal/cardiac muscle

Question 10

stem cells

Answer 10

cells that remain incompletely differentiated throughout life

divide to: replace cells that died from apoptosis, or to produce another stem cell

Question 11

properties of stem cells

Answer 11

self renewal: one cell form each mitotic division remains a stem cell (undifferentiated)

asymmetric replication: 2 cells from mitotic division are not identical – one differentiates, the other does not

Question 12

types of stem cell potency

Answer 12

stem cells have different differentiation potential

totipotent

pleuripotent

multipotent

unipotent

Question 13

totipotent stem cells

Answer 13

can produce all tissue types and placenta

cells generated by the first few divisions of fertilized ovum

Question 14

pleuripotent stem cells

Answer 14

can produce all embryonic tissue types

Question 15

multipotent stem cells

Answer 15

can produce a few related cell types

ex. hemocytoblasts

Question 16

unipotent stem cells

Answer 16

can produce 1 cell type only

Question 17

embryonic vs. adult (somatic) stem cells

Answer 17

embryonic are pleuripotent

adult may have less capacity

Question 18

growth factos

Answer 18

small hormone-like proteins that are chemical triggers for cellular proliferation

contribute to tissue regeneration & wound healing

Question 19

how are growth factors named

Answer 19

for tissue of origin

EGF: epidermal growth factor

TGF: transforming growth factor

VEGF: vascular endothelial cell growth factor

Question 20

mechanism of growth factors

Answer 20

bind to surface receptors, activate 2nd messenger systems, increase expression of specific genes –> cellular division

Question 21

ECM includes

Answer 21

basement membrane (borders epithelial tissue)

interstitial matrix (between cells of connective tissue)

Question 22

ECM contains

Answer 22

protein fibers: collagen & elastin

water-hydrated gels: proteoglycans & hyaluronic acid

adhesion glycoproteins: fibronectin & laminin

Question 23

cells have integrins that…

Answer 23

bind to adhesion molecules

Question 24

fibroblasts produce…

Answer 24

collagen fibers

Question 25

functions of ECM

Answer 25

provides turgor to soft tissue (structure of proteins is different between old/young skin b/c of H2O loss) regulates cell movement & differentiation scaffold for tissue renewal after injury

Question 26

primary goal of healing by conn. tissue repair

Answer 26

fill gap created by injury and restore structure of neighboring tissues

Question 27

regeneration

Answer 27

restoration of injured tissue to a normal state

Question 28

scar formation

Answer 28

replacement of injured tissue with fibrous connective tissue

Question 29

phases of tissue repair

Answer 29

angiogenesis & ingrowth of granulation tissue emigration of fibroblasts and deposition of ECM maturation and remodeling of fibrous tissue

Question 30

angiogenesis

Answer 30

phase 1 of tissue repair growth of new blood vessels stimulated by VEGF & FGF new vessels are initially leaky --> wound edema persisting after inflammation

Question 31

ingrowth of granulation tissue

Answer 31

phase 1 of tissue repair granulation tissue: conn. tissue that fills injured area while necrotic debris is removed requires new blood vessels

Question 32

emigration of fibroblasts and deposition of ECM

Answer 32

fibroblasts migrate to wound and proliferate deposit ECM including collagen stimulated by FGF & TGF-beta

Question 33

maturation and remodeling of fibrous tissue

Answer 33

transition from granulation tissue to scar tissue ECM remodeled by metaloproteases

Question 34

healing of skin wounds

Answer 34

involves both epithelium & conn. tissue primary intent secondary intent

Question 35

primary intent

Answer 35

sutured surgical incision -- only for clean wounds

Question 36

secondary intent

Answer 36

wound left open and irrigated for larger wounds with tissue loss & contaminated wounds

Question 37

phases of wound healing

Answer 37

inflammatory proliferative remodeling

Question 38

inflammatory phase (phase 1 of wound healing)

Answer 38

starts at time of injury blood clotting and vasoconstriction stop bleeding vessels dilate to bring inflammatory cells to the wound neutrophils/macrophages phagocitize bacteria and release growth factors GF stimulate angiogenesis & attract fibroblasts

Question 39

proliferative phase (phase 2 of wound healing)

Answer 39

starts 2-3 days post-injury fibroblasts secrete collagen and produce GF endothelial cells proliferate and migrate to close wound edges granulation tissue forms collagen synthesis continues

Question 40

remodeling phase (phase 3 of wound healing)

Answer 40

starts at ~3 weeks post-injury collagen is remodeled and epithelium reestablished the wound contracts -- limits scar size but can also limit joint movement

Question 41

keloid

Answer 41

excess scar tissue production

Question 42

factors affecting wound healing

Answer 42

nutritional status blood flow impaired inflammatory response infection, wound separation, foreign bodies

Question 43

nutritional status

Answer 43

wound healing requires adquate protein, carbohydrates, & vitamins

Question 44

blood flow for wound healing

Answer 44

O2 needed for collagen synthesis and phagocytosis ischemic tissue heals slowly

Question 45

impaired inflammatory response

Answer 45

disorders that impair action of phagocytes slow wound healing

Question 46

infection, wound separation, foreign bodies

Answer 46

uncontaminated wounds with no foreign bodies and approximated edges heal the fastest