A/21

Question 1

What is hypertrophy?

Answer 1

Increase of cell size and functional capacity

Question 2

What generates hypertrophy?

Answer 2

1. functional demand (mechanical trigger)
2. hormones (trophic triggers)
3. growth factors

Question 3

Cellular remodelling in hypertrophy (6)

Answer 3

• proteins not needed are degraded
• increased protein translation
• increased gene expression
• increased cell survival
• remodelling ECM
• increased DNA content (polyploidy)

Question 4

On which cells does hypertrophy act?

Answer 4

On cells that have a limited or no capacity at all to divide

Question 5

Example of hormone that causes hypertrophy

Answer 5

estrogen in pregnancy makes SMC in uterus produce more proteins

Question 6

2 pathways for hypertrophy

Answer 6

• PIP3 kinase / AKT pathway (physiological)

- G protein coupled (pathological)

Question 7

What is atrophy?

Answer 7

• reduction in size of an organ

- loss of cell matter

Question 8

Causes of atrophy (4)

Answer 8

• reduced functional demand
• inadequate O2 and nutrition supply
• interruption of trophic signals
• aging

Question 9

Mechanism of atrophy (4)

Answer 9

• protein synthesis decreases
• protein degradation
• decreased gene expression
• increased autophagy

Question 10

How does protein degradation happen in atrophy?

Answer 10

ubiquitin proteasome pathway (marked with ubiquitin)

Question 11

Examples of atrophy

Answer 11

• brown atrophy of the heart
• cerebral atrophy
• cahexia (causes osteoporosis)