5. Cell Response to Injury: Ultra-structural Changes

Question 1

What are the consequences of cell injury?

Answer 1

Damage to cellular components

Question 2

Ca2+ levels are kept in check by which enzymes?

Answer 2

ATP dependent enzymes

Question 3

If acid hydrolases are activated which pathway of cell death will occur? why?

Answer 3

necrosis - leakage of enzymes

Question 4

what does ribosome detachment from Rough ER result in?

Answer 4

decreased protein synthesis

Question 5

function of smooth ER?

Answer 5

lipid production, detoxification

Question 6

function of rough ER?

Answer 6

protein production for export

Question 7

function of golgi apparatus?

Answer 7

protein modification and export

Question 8

function of perixisome ?

Answer 8

lipid destruction

Question 9

function of lysosome

Answer 9

protein destruction

Question 10

3 things which cause damage to mitochondria? (sub-lethal)

Answer 10

hypoxia, hypoglycaemia, toxins

Question 11

4 feautures of sub-lethal mitochondrial damage

Answer 11

1. mitochondrial swelling
2. vacuolation
3. damaged and distorted cristae
4. reduction in oxidative phosphorylation - reduced ATP

Question 12

what process removes damaged cell components?

Answer 12

autophagy

Question 13

4 effects of low ATP

Answer 13

1. reduced Na/K pump
2. failure of Ca2+ homeostasis
3. increased anaeorobic glycolysis
4. detachment of ribosomes from rough ER

Question 14

what is disrupted if there is damage to the mitochondria?

Answer 14

ATP production

Question 15

effects of reduced activity of Na/K pump

Answer 15

• increase in intracellular Na
• increase in water via osmosis
• cellular swelling

Question 16

what does increased anaerobic glycolysis cause

Answer 16

decreased pH (lactic acid) 
clumping of nuclear chromatin

Question 17

effect of detachment of ribosomes from rough ER?

Answer 17

decreased protein syntehsis

Question 18

what is the normal concentrtion of Ca2+ intracellular? why?

Answer 18

low - regulated by ATP dependent pumps

Question 19

what occurs in terms of intracellualr Ca2+ when ATP decreased?

Answer 19

Intracellular Ca2+ increases - activates enzymes

Question 20

what 4 enzymes are activated as a result of increased Ca2+ concentration?

Answer 20

1. phospholipases
2. endonucleases
3. proteases
4. ATPase

Question 21

what occurs when intracellar Ca2+ is further increased?

Answer 21

irreversible/point of no return/lethal injury

Question 22

3 causes of membrane damage

Answer 22

1. decreased ATP levels - cellular swelling
2. leakage of lysosomal enzymes into cytosol
3. cytoskeleton damage

Question 23

what enzymes leak out of lysosomes into the cytosol?

Answer 23

RNAses
DNAses
Proteases

Question 24

what effects do the release of lysosomal enzymes into the cytosol cause?

Answer 24

enzymatic digestion and irreversible damage

Question 25

2 irreversible nuclear changes ?

Answer 25

1. pyknosis = condensation of chromatin in nucleus - leads to apoptosis and necrosis
2. karyolysis = dissolution of nucleus

Question 26

desribe ER damage

i) reversible
ii) irreversible

Answer 26

i) swelling

ii) disintegration - loss of ribosomes

Question 27

desribe mitochondria damage

i) reversible
ii) irreversible

Answer 27

i) loss of cristae

ii) loss of integrity

Question 28

desribe lysosome damage

i) reversible
ii) irreversible

Answer 28

i) swelling

ii) rupture and leakage of enzymes

Question 29

desribe plasma membrane damage

i) reversible
ii) irreversible

Answer 29

i) membrane blebbing

ii) disruption

Question 30

desribe nucleus damage

i) reversible
ii) irreversible

Answer 30

i) chromatin clumping

ii) Pyknosis/karyolysis

Question 31

2 types of irreversible injury

Answer 31

apoptosis and necrosis

Question 32

3 features of necrosis

Answer 32

1. loss of membrane
2. leakage of cellular constituents
3. inflammatory response

Question 33

what is karyorrhexis? when is it seen?

Answer 33

fragmentation of nucleus - necrosis

Question 34

describe stage 1 necrosis

Answer 34

1. distinct nucleus and nucleolus

2. cytoplasm is pale pink - due to cellular RNA

Question 35

how many stages of necrosis?

Answer 35

4

Question 36

describe stage 2 necrosis

Answer 36

1. cytoplasm shrinks
2. loss of ribosomes
3. nucleus shrinks and becomes basophilic- due to cessation of DNA transcription

Question 37

describe stage 3 necrosis

Answer 37

1. cell membrane breaks down - irregular shape

2. karyorrhexis

Question 38

describe stage 4 necrosis?

Answer 38

1. cytoplasm eosinophilic

2. karyolysis - nucleus completely dissolved

Question 39

3 cell changes in necrosis?

Answer 39

1. cells stain pink
2. cells lose definition
3. distinct nuclear changes

Question 40

4 cell changes in apoptosis

Answer 40

1. cells shrink
2. chromatin condensation in nucleus
3. formation of apoptotic bodies
4. phagocytosis of apoptotic bodies by macrophages

Question 41

4 stages of apoptosis

Answer 41

1. signalling
2. execution
3. degradation
4. phagocytic

Question 42

what is the signalling phase triggered by?

Answer 42

extrinsic or instrinsic pathway

Question 43

in which phase is the point of no return

Answer 43

execution

Question 44

what occurs in the degradation phase>

Answer 44

activation of DNAases - break down nuclear envelope

Question 45

how are apoptotic bodies (AB) broken down in phagocytic phase?

Answer 45

1. AB express phosphatidylserine on surface
2. allows attachment of thrombospondin
3. macrophages recognise thrombospondin

Question 46

which cellular markers are used to detect apoptotic bodies?

Answer 46

Annexin V

Question 47

what occurs in the execution phase?

Answer 47

endonucleases break down chromosomes

Question 48

in which stages of apoptosis are apoptotic bodies formed?

Answer 48

3 - degradation

Question 49

is swelling a characterisitic of apoptosis or necrosis?

Answer 49

necrosis

Question 50

is cell shrinkage a characterisitic of apoptosis or necrosis?

Answer 50

apoptosis