Pathology Lecture 5 - Aetiology of Disease and non-lethal cell injury

Question 1

Describe possible outcomes for a cell subjected to stress - there are 3

Answer 1

1. Adaption and improved funtion
2. Reduced health followed by recovery to the same level
3. With persistent stress, cell injury and/or death

Question 2

Give an example of a physical, environmental, genetic and immune function stimuli that may cause cellular injury

Answer 2

Physical - mechanical/heat
Env. - bacterial
Genetic - inherited
Immune function - auto-immune

Question 3

What is the connection between pathogenesis and morphology?

Answer 3

Pathogenesis causes changes in morphology

Question 4

Describe features commonly found in injured cells - reversible

Answer 4

Swelling, cytoplasmic inclusions, accumulations and pigments, steatosis

Question 5

Describe features commonly found in injured cells - irreversible

Answer 5

Abnormal mitochondria, irregular cell contours, eosinophilia and nuclear deformities

Question 6

How can swelling of the cell occur, and what does it look like?

Answer 6

Can occur through failure of a membrane pump, or could be adaptive - this is called membrane blebbing and can occur in hypoxia to increase surface area, facilitating uptake of oxygen.

Swelling in toxic injury: cell looses organised structure, ribosomes detach and lipid accumulates.

Hydropic swelling makes a cell look pale and washed out
Excess liquid in cell dilates the cell substructure

Question 7

What are inclusions?

Answer 7

Something that’s not usually present, and is described according to staining properties e.g. a Hyaline inclusion would be glassy and pink in appearance.
An example of an inclusion is a Mallory body, often found in alcoholic livers.
However, they can also be viral

Question 8

What are accumulations?

Answer 8

A build up of a product of the body, which should not be there.
These can be intracellular or extracellular.
Intracellular: glycogen accumulates in the lysosome in alpha-gluconidase deficiency
Extracellular: amyloid can get deposited in the myocardium, which will eventually interfere with vascular supply

Question 9

What are pigments?

Answer 9

Coloured substances, which can be endogenous or exogenous
Endogenous - normally present, abnormally accumulated
Exogenous: not normally present

Question 10

Describe Steatosis, and where it is particularly relevant

Answer 10

Steatosis is the abnormal accumulation of lipid.
Organs may appear enlarged and yellow in appearance, with abnormally large lipid droplets displaying mitochondria clustered around them.
Benign in isolation, but it does sensitize cells to inflammation, which can lead to hepatitis, then cirrhosis, then fatal liver failure

Question 11

Why might mitochondria appearance change, and what could this change look like?

Answer 11

Mitochondria can change in response to Anoxia - absence of oxygen
They become greatly swollen and lose their parallel arrays of cistaes

Question 12

Why would Eosinophilia be seen in irreversible cell injury?

Answer 12

Denatured proteins in the cytoplasm of cells bind eosin, and less RNA production leads to loss of basophilia

Question 13

What is a nuclear abnormality we might see in irreversible cell injury?

Answer 13

Multinucleation - nuclei divide without cell pulling them apart