MoD: Cell Injury and Death

Question 1

Hyperplasia?

Answer 1

Cells makes more cells

Question 2

Hypertrophy?

Answer 2

Cells gets bigger

Question 3

Metaplasia?

Answer 3

Transformation of one type of differentiated cell into another. Particularly in association with chronic cellular injury and repair, eg) smoking

Question 4

What are 5 mechanisms of cell injury?

Answer 4

1) Mechanical injury/ Membrane integrity (trauma, osmotic pressure)
2) Energy Failure (reduced oxygen/ glucose eg if a thrombus blocks a blood vessel)
3) Ionising Radiation (generation of free radicals and direct damage to macromolecules)
4) Infectious Organism (bacterial toxin, exo/endotoxins)
5) Chemical Injury (eg C. diff. = membranous colitis. Cyanide= blocks electron transport chain)

Question 5

What are 4 differences between apoptosis and necrosis?

Answer 5

Apoptosis: -‘Programmed Cell Death’

• Signals cause death
• No harmful products released
• Takes energy

Necrosis: -Abnormal unintended cell death

• In response to injury, incites inflam. response
• Causes release of harmful products
• Doesn’t expend energy

Question 6

What are caspases?

Answer 6

Caspases are a family of protease enzymes playing essential roles in programmed cell death. (have specific cysteine protease activity)

Question 7

What are the 4 types of necrosis?

Answer 7

1) Coagulative (most common)
2) Caseous
3) Colliquative
4) Gangrene

Question 8

What is coagulative necrosis?

Answer 8

Typical of ischaemic injury (not brain)
Denaturation of intracytoplasmic protein
Dead tissue becomes firm and swollen

Question 9

What is caseous necrosis?

Answer 9

Tuberculosis
Granulomatous inflammation (dead tissue lacks any structure)

Question 10

What is colliquative necrosis?

Answer 10

Brain. (neural tissue has little supporting tissue and liquefies upon cell death)
The site is eventually marked by a cyst