Tissue Injury

Question 1

what are the two main processes that resolve cell injury

Answer 1

regeneration
repair

Question 2

what are the mechanisms of cell injury

Answer 2

ischemia
infectious agents
immune reactions
genetic alterations

Question 3

what are the two infectious agents

Answer 3

bacteria
viruses

Question 4

what is ischemia

Answer 4

blood flow below the minimum necessary to maintain cell homeostasis and cell homeostasis
and metabolic function

Question 5

what can ischemia result in

Answer 5

hypoxia or anoxia in tissue
decreased nutritional delivery
decreased removal of waste

Question 6

how do bacterial agents affect cells

Answer 6

invade tissue
release exotoxins and endotoxins
cause cell lysis and degradation of ECM that aids in the spread of infection

Question 7

what are two ways a virus may get into a host

Answer 7

indirect or direct

Question 8

what is direct virus effect

Answer 8

usually found with RNA
kill by disturbing various cellular processes or disrupting the integrity of the cell nucleus/plasma membrane

Question 9

what is indirect virus effect

Answer 9

integrate themselves into the cellular genome
encode production of foreign proteins that are not recognized by body’s immune system

Question 10

what are the inflammatory cells

Answer 10

neutrophils
macrophages
T/B lymphocytes
mast cells
basophils

Question 11

hallmarks of irreversible cell injury

Answer 11

alternations in the cell nucleus
mitochondria
lysosomes
rupture of cell membrane

Question 12

2 mechanisms of tissue healing

Answer 12

regeneration and repair

Question 13

what are regeneration / repair

Answer 13

regeneration - regrowth of original tissue

repair - formation of a connective tissue scar

Question 14

what cells are involved in tissue healing

Answer 14

fibronectin
proteoglycans
elastin
collagen

Question 15

function of fibronectin

Answer 15

“glue” for substances and cells
attracts fibroblasts and macrophages

Question 16

what do proteoglycans and elastin do

Answer 16

bind to fibronectin and collagen to stabilize tissue undergoing repair

water retention

Question 17

function of collagen

Answer 17

most important protein to provide structural support and tensile strength

Question 18

how does collagen change during the maturation process

Answer 18

moves from type 3 to 1
3 being most immature, 1 being most mature

Question 19

tell me about type 1 collagen

Answer 19

main component of mature scars
predominant in strong tissues such as tendons and bones

Question 20

tell me about type 2 collagen

Answer 20

assembled thin supporting filaments
predominant type of collagen found in cartilage

Question 21

tell me about type 3 collagen

Answer 21

assembled into thin filaments
makes tissue strong but supple and elastic
prevalent in newborns

Question 22

what are two current theories proposed to explain collagen realignment

Answer 22

tension vs induction

Question 23

what is the tension theory

Answer 23

as collagen gets laid, stress on the tissue will regulate how much collagen is laid down

Question 24

what is the induction theory of scar formation

Answer 24

the body knows what to do/has its own blueprint and lays down collagen according to that

Question 25

4 phases of healing

Answer 25

hemostasis and degeneration inflammation proliferation and migration remodeling and maturation

Question 26

when does hemostasis and degeneration occur?

Answer 26

immediately after an acute injury to help the body try to stop bleeding and initiate coagulation

Question 27

characteristics of degeneration/hemostasis

Answer 27

formation of hematoma necrosis of dead cell start of inflammatory cell response

Question 28

when does inflammatory phase begin

Answer 28

once blood clot forms

Question 29

what occurs in the inflammation stage

Answer 29

vasodilation and increased capillary permeability to activate movement of cells to the wound site

Question 30

what coordinated reaction of body tissues involved in inflammation

Answer 30

vascular humoral neurologic cellular responses

Question 31

functions of the inflammatory reactions

Answer 31

inactivate the injurious agent break down and remove dead cells initiate the healing of tissue

Question 32

tell me about the clinical manifestations of acute inflammation

Answer 32

redness, swelling, increased temperature, pain, decreased function

Question 33

primary outcomes of acute inflammation

Answer 33

complete resolution of normal tissue structure healing of scar formation chronic fibrosis

Question 34

vascular changes of acute inflammation

Answer 34

leakage of protein poor fluid (transudate) into interstitial spaces leakage vessels become engorged with blood cells causing a slowing of blood flow leukocytes accumulate and adhere to endothelial cells adhesion of glycoproteins

Question 35

what are the predominant leukocytes present in acute inflammation

Answer 35

neutorphils

Question 36

chemical mediators of inflammation

Answer 36

histamine platelet-activating factor prostaglandins leukotrienes cytokines

Question 37

what is the purpose phagocytosis

Answer 37

inactivation and remove inflammatory stimulus in order to begin healing

Question 38

explain phagocytosis what are the most important phagocytes

Answer 38

ingestion of microorganisms, other foreign substances, necrotic cells and connective tissue monocytes and macrophages

Question 39

what are the hallmark signs of acute inflammation

Answer 39

pallor - pain calor - heat rumbor - redness tumor - swelling loss of function

Question 40

what is proliferation and migration

Answer 40

revascularization and rebuilding of tissue fibroblasts drawn to the matrix and synthesis of new collagen/elastin/and proteogylcans

Question 41

what is the time frame of proliferation and migration

Answer 41

within 2 days of wound or injury

Question 42

what is neovascularization / angiogenesis? when does it occur?

Answer 42

establishment of a network that can transport oxygen and nutrients to support metabolism and healing proliferation and migration

Question 43

tell me about remodeling and maturation

Answer 43

balance between tissue synthesis and degradation

Question 44

how long can remodeling and maturation take

Answer 44

years as initial collagen strands are broken down and rearranged due to stress

Question 45

tell me about the scar tissue changes during maturation phase

Answer 45

reduced and remodeled - smoother and stronger less red due to decreased concentrations of blood vessels

Question 46

what are myofibroblasts

Answer 46

abundant contractile proteins to contribute to shrinkage of healing tissue

Question 47

scar formation process

Answer 47

initial collagen (type3) remodeling (3 to 1) consolidation maturation

Question 48

hypertrophic scars

Answer 48

elevated collagen that is laid down within the borders

Question 49

keloid scars

Answer 49

outside of OG borders, laid in circular fashion

Question 50

what is the expected regeneration of peripheral nerves

Answer 50

undergoes myelin degeneration and axonal fragmentation within 24 hours axonal sprouts occur regeneration of 1 inch per month