MOD (minus lecture 1)

Question 1

Causes + mechanisms of cell damage/death (6)

Answer 1

Genetic
Inflammation
Physical
Traumatic damage
Infection
Chemical

Question 2

What three mechanisms can cause cell death? (3)

Answer 2

Necrosis
Apoptosis
Autophagic cell death

Question 3

What happens in necrosis? (2)

Answer 3

Most common cause

Occurs after ischaemia, trauma + chem injury

Question 4

What happens in apoptosis? (3)

Answer 4

Programmed cell death
Eliminates unwanted host cells
Through activation of co-ordinated, internally programmed events by a dedicated set of gene products

Question 5

What happens in autophagic cell death? (4)

Answer 5

Degradation of normal proteins involved in cellular modelling Found during metamorphosis/
ageing/differentiation
Also for digestion + removal of abnormal proteins that would normally accumulate
E.g. death of breast Ca cells induced by tamoxifen

Question 6

What are possible causes of necrosis? (2)

Answer 6

Usually lack of blood supply to cells or tissues

E.g. infection, injury, cancer, inflammation, infarction

Question 7

What happens to pH + pO2 as you increase distance from a blood vessel? (1)

Answer 7

pH + pO2 decreases

Question 8

Summary of necrosis (7)

Answer 8

1. Whole groups of cells are affected
2. Result of injurious agent or event
3. Reversible events proceed irreversible
4. Energy deprivation causes changes (e.g. cells can’t produce ATP)
5. Cells swell due to influx of water (ATP is required for ion pumps to work)
6. Rupture lysosomes rel enzymes cause haphazard destruction of organelles + nuclear material
7. Cellular debris stimulates inflamm cell response

Question 9

What are the nuclear changes of necrosis? (3)

Answer 9

1. Chromatic condensation/shrinkage
2. Fragmentation of nucleus
3. Dissolution of chromatin by DNase causing a fading in basophilia of chromatin

Question 10

What are the cytoplasmic changes of necrosis? (3)

Answer 10

Opacification = denaturation of proteins with aggregation
Eosinophilia = exposure of basic amino groups
Complete digestion of cells by enzyme causes cell to liquify -> liquefactive necrosis

Question 11

What are the biochemical changes of necrosis? (3)

Answer 11

Rel of enzymes e.g. creatine kinase or lactate dehydrogenase

Rel of proteins e.g. myoglobin

Question 12

Clinical investigation associated with cell death (4)

Answer 12

Muscular dystrophy - damaged muscles rel creatine kinase + LDH (M3 + MH3 isoforms)
Heart attack - damaged muscle cells release LDH (H3 + HM3)
Bone + liver disease - damaged tissues release alkaline phosphatase + LDH
Haemolytic anaemias - damaged RBCs release LDH1/2

Question 13

What are the 5 types of necrosis? (5)

Answer 13

Coagulative necrosis
Liquefactive necrosis
Caseous necrosis
Fatty necrosis
Fibrinoid necrosis