Muscle Hypertrophy/ Satellite Cells W6 Flashcards
What is hyperplasia?
Increase in number of fibres within a muscle
What is hypertrophy?
Increase in sarcomeres and myofibrils in parallel
Causes contractile elements to enlarge alongside enlarging extracellular matrix
Protein synthesis exceeds protein breakdown
What muscle fibres are most responsive to hypertrophy?
Fast-twitch
What is sarcoplasmic hypertrophy?
Increase in various noncontractile elements and fluid
Non-functional
Mediates increases in protein synthesis-= greater contractile growth
What type of tissue is muscle?
Postmitotic (Does not undergo significant cell replacement)
What maintains skeletal mass (apoptosis)?
Balance between protein synthesis/degradation
What mediates muscle hypertrophy?
Satellite Cells
What are satellite cells?
Proliferate and fuse to existing cells to create new myofibers
How do satellite cells facilitate muscle hypertrophy?
Donate extra nuclei to muscle hypertrophy
Retain mitotic capability
Co-express various myogenic regulators
How does donating extra nuclei to muscle hypertrophy facilitate muscle hypertrophy?
Increases capacity to synthesize new contractile proteins
How does retaining mitotic capability facilitate muscle hypertrophy?
Serve as the pool of a myonuclear to support muscle growth
How does expressing various myogenic regulators facilitate muscle hypertrophy?
Aid in muscle repair, regeneration and growth
What are the different myogenic regulators?
Myf5
MyoD
Myogenin
MIRF4
What does the myonucleus do?
Regulates mRNA production for finite sarcoplasmic volume
Is increased in proportion to increased fibre size
How does the myonuclear domain allow for hypertrophy to occur?
Increase in number of domains
Increase in size of existing domains
