Module 6 Flashcards
Why do we study inactivity?
- Injury
- Illness
- Space flight
- Long term model of sedentary behavior
- Model of accelerated ageing
What are common ways to study inactivity?
- Bed rest
- Cast
- Brace
- Step reduction
- Long term inactivity?
How much muscle do old people lose per year?
0.5-1%
How much muscle can you lose in 2 weeks of disuse?
5%
What are the two main pathways of protein breakdown?
Autophagy and the ubiquitin-dependent system
These pathways are essential for cellular homeostasis and protein turnover.
What is autophagy often described as?
‘Self-eating’ process of the cell
It involves the engulfing and breakdown of cellular components by lysosomes.
Which cellular components are involved in autophagy?
Damaged organelles like mitochondria
Autophagy helps recycle cellular components and maintain cell health.
What effect does mTOR have on autophagy?
Inhibits autophagy
mTOR is a key regulator of cell growth and metabolism.
What marks proteins for degradation in the ubiquitin-dependent system?
Ubiquitin
This tagging process signals the proteasome to degrade the marked proteins.
What role does the transcription factor FOXO play?
Coordinates activation of autophagy and the proteasome pathway
FOXO is involved in stress responses and regulates various cellular processes.
Which inflammatory pathway can influence protein breakdown?
NFκB
NFκB is activated during inflammation and can affect various cellular processes.
What types of inflammation can activate NFκB?
Low-grade (like in diabetes) and high-grade (like in sepsis or cancer cachexia)
Both types of inflammation can impact muscle protein metabolism.
Which genes are upregulated in the ubiquitin-dependent system?
Atrogin-1 and MuRF1
These genes play a critical role in muscle protein degradation.
What is the primary driver of disuse atrophy in humans?
Decreased muscle protein synthesis (MPS)
This decline often explains muscle loss without significant changes in breakdown.
True or False: The decline in muscle protein synthesis can explain observed muscle loss.
True
This highlights the importance of MPS in maintaining muscle mass.
