Cell Death

Question 1

What does prolonged hypoxia cause?

Answer 1

Prolonged hypoxia can cause myocardial infarction or a heart attack. This is as the intracellular proteins have leaked through the damaged cell membrane.

Question 2

What happens to staining during a myocardial infarction?

Answer 2

There is increased staining of eosin due to denaturing of proteins (exposes more to the stain) and decreases haemotoxylin staining as the nuclei has been reduced.
Therefore, more pink staining, less blue.

Question 3

What inflammatory responses occur with a myocardial infarction?

Answer 3

The loss of basophillic RNA causes edema and accumulation of fluid, forming more gaps in the tissue. There is also an accumulation of inflammatory cells.

Question 4

What nuclear changes occur during necrosis?

Answer 4

Nuclear changes during necrosis occur due to DNA breakdown. These include:

• Pyknosis shrinkage
• Increased basophilia
• Karyorrhexia nuclear fragmentation
• Karyoloysis decreased basophilia

Question 5

What are the the types of necrosis?

Answer 5

The types of necrosis are:

• Liquefactive - complete digestion of cells when infection occurs
• Denaturation coagulative - occurs in solid organs
• Fat - fat in membrane is broken down, seen in flammation of the pancreas
• Caseous - digestion of tissues due to bacterial infection
• Fribrinoid - occurs in blood vessels due to deposition of immune complexes
• Gangrenous - occurs in lower limbs

Question 6

What are the visible changes during apoptosis?

Answer 6

• Cell shrinks
• Nuclear chromatin condenses and fragments
• Apoptotic bodies

Question 7

What is apoptosis used for?

Answer 7

Apoptosis is used for...
Embryogenesis - removal of webbing
Involution - shrinking of organs
Cell loss after proliferation
Elimination of old cells
Removal of self-reactive t-cells

Question 8

What are the two pathways of apoptosis?

Answer 8

The two pathways of apoptosis are the mitochondrial and extrinsic pathway.

Question 9

What triggers the activation of the mitchondrial pathway of apoptosis?

Answer 9

Mitchondrial pathway is activated by growth factors, DNA damage or protein misfolding.

Question 10

What activates the extrinsic pathway of apoptosis?

Answer 10

The extrinsic pathway of apoptosis is triggered by…

• Cytotoxic t-cells responding to Fas and TNF receptor ligand reactions
• Infection