7: Mechanisms of Cell Death and Tissue Repair

Question 1

homeostasis is when a cell is at

Answer 1

optimal function, meeting physiological demands

Question 2

reversible changes in response to cell’s environment/ stressors

Answer 2

adaptation

Question 3

_____ happens when cells can not adapt or are at the max adaptive response to stimuli

Answer 3

cell injury

Question 4

factors affecting cell injury include

Answer 4

nature/ duration/ severity + cell type/ adaptation + activation of multiple mechanisms

Question 5

list the 6 mechanisms of cell injury

Answer 5

mitochondrial damage
abnormal calcium homeostasis
DNA damage
membrane damage
ER stress
oxidative stress

Question 6

describe why mitochondrial damage causes cell injury

Answer 6

essential for survival by producing ATP, but is also a major source of reactive oxygen species production + activates cell death pathways (apoptosis, autophagy, etc)

Question 7

describe why abnormal calcium homeostasis causes cell injury

Answer 7

increased Ca activates Ca dependent enzyme degradation

Question 8

describe how ER stress causes cell injury

Answer 8

releases Ca stores, misfolded proteins

Question 9

chemical injury directly targets

Answer 9

organelles

Question 10

chemical injury requires __________ activation and often trigger an _____ response

Answer 10

metabolic activation
inflammatory response

Question 11

chemical injury is
1. selective, not based on kinetics
2. nonselective, not based on kinetics
3. nonselective, based on kinetics
4. selective, based on kinetics

Answer 11

4

Question 12

cellular damage occurs when __________are overwhelmed = damage to membrane, mitochondria, ER, DNA, proteins

Answer 12

antioxidant systems

Question 13

hypoxia

Answer 13

tissues are starved of oxygen- 1-2% oxygen

Question 14

ischemia

Answer 14

blood flow is cut off to tissues (no blood/ oxygen delivered but also no removal of metabolic wastes)

Question 15

mild ischemic/ hypoxic injury is reversible if

Answer 15

tissue oxygen supply is restored

Question 16

anoxia is

Answer 16

0% oxygen left

Question 17

reversible cell injury is _______ insult or ______ duration

Answer 17

milder
shorter

Question 18

describethe hibdernating myocardium

Answer 18

Delayed return to function once regional flow reestablished because muscle was hibernating to try to survive longer

Question 19

loss of blood flow and oxygen results in (series after ATP drops)

Answer 19

↓ ATP results in
↓ ion pumps (no ATP to drive pumps Na/K levels change = cell swelling
↑ glycolysis (from ↓ oxphos)
↓pH (lactic acid production), disruption of synthesis/ storage

Question 20

loss of blood flow and oxygen for too long =

Answer 20

membrane injury, calcium influx activates enzymes to break down cell = lysosomal breakdown of organelles/ proteins = autodigestion = protein markers released

Question 21

the point at which the cell becomes unable to recover its normal morphology and function even if all processes leading to its dissolution stopped

Answer 21

cell death

Question 22

what is programmed cell death

Answer 22

a active process that depends on the execution of a defined sequence of signaling events
Dependent on genetic encoded signals or activities
Not the same as apoptosis

Question 23

what are the 3 distinct routes of cellular catabolism

Answer 23

apoptosis
autophagy
necrosis

Question 24

accidental necrosis is a _________ process

Answer 24

passive
energy independent

Question 25

give 4 characteristics of accidental necrosis

Answer 25

Pathological (following noxious stimuli) Occurs synchronously in multiple cells of a tissue region Early loss of membrane integrity Generalized cell and nuclear swelling Nuclear chromatin disintegration Inflammatory reactions (triggered as membrane dies) Energy independent (dramatic irreversible drop in ATP) Historically regarded as unregulated cell death

Question 26

4 morphological descriptions of necrosis

Answer 26

coagulative/ infarct liquefactive fatty caseous

Question 27

describe coagulative/ infarct necrosis

Answer 27

Infarction- necrosis caused by ischemia or anoxia (heart attack/ stroke) Tissue shows red staining indicating clot proteins (Ex- fibrin), anoxic injury Loss of blood supply

Question 28

describe liquefactive necrosis

Answer 28

Death of tissue releases many lytic enzymes = degrades surrounding tissues Fluid remains following digestion of necrotic tissue

Question 29

describe fatty necrosis

Answer 29

Pancreas release of enzymes = lipase digests fat = produces soaps microscopically(saponification) Loss of cellular membrane Necrotic fat cells Release of fatty acids combined with minerals

Question 30

describe caseous necrosis

Answer 30

Combination of coagulative and liquefactive necrosis Granulomas (cluster of WBCs) as a result of immune response

Question 31

apoptosis is critical in the

Answer 31

maintenace of normal organ and tissue homeostasis sculpting development and maintaining normal function

Question 32

apoptosis is a ______ process

Answer 32

active

Question 33

apoptosis is _____ controlled

Answer 33

geneticallly

Question 34

which evokes less inflammatory response, necrosis or apoptosis

Answer 34

apoptosis

Question 35

autophay is

Answer 35

Self digestive process to remove damaged proteins/ organelles by fusing with lysosomes for digestion

Question 36

which does not display chromatin condensation 1. ncrosis 2. apoptosis 3. autophagy

Answer 36

3

Question 37

autophagy is caspase ____ (dep/ indep)

Answer 37

independent

Question 38

3 major categories of autophagy

Answer 38

macroautophagy microautophagy chaperone mediated autophagy

Question 39

macroautophay is the

Answer 39

fusion of autophagosome with lysosome → degradation in lysosome → efflux of metabolites

Question 40

microautophay is

Answer 40

specific type of organelle (may be damaged) is sequestered into lysosome for degradation

Question 41

chaperone mediated autophagy is

Answer 41

uses specific proteins (LAMP-2A, Hsp70 chaperone) to target specific motif on proteins → translocates to lysosome → degradation → efflux

Question 42

autophahy is often associated with

Answer 42

cell survival

Question 43

autophagy is triggered by

Answer 43

nutrient deprivation- enables cells to restore sufficient energy levels + promotes viability

Question 44

in early stages after cell death, debris is cleaned up by __________ that accumulate over ______. this process begins within ______

Answer 44

cleaned up by phagocytes that accumulate over few days starts within minutes

Question 45

in early tissue repair, tissue ____ begins to repair, there is new _______ to provide ________ , also known as

Answer 45

tissue scaffold new blood supply granulation tissue

Question 46

when does early tissue repair start happening

Answer 46

several days post injury

Question 47

in late tissue repair, ____ proliferate and synthesize collagen

Answer 47

fibroblasts

Question 48

3 responses to abnormal physiologic stress

Answer 48

tissue adaptations metabolic responses growth responses