Lecture 8 Flashcards
What are the two key proteins that make up the myofilament?
Actin and myosin.
What event allows a cross-bridge to form?
The presence of calcium.
What event causes the cross-bridge to be released?
The binding of ATP to the myosin head.
At what point in the cross-bridge cycle does the myofilament slide?
When the myosin head uses its stored energy to pull on the actin filament.
What are the two determinants of skeletal muscle force generation?
The number of muscle fibres recruited and the rate of muscle stimulation.
What is recruitment in muscle force generation?
The process of activating more muscle fibres to produce more force.
What happens when many action potentials are fired in rapid sequence?
A sustained release of calcium, sustained actin-myosin interaction, and sustained contraction (summation).
What is tetanus in muscle contraction?
The maximal signaling and contraction capability of the muscle.
How does the length-tension relationship affect muscle strength?
Each muscle has an optimal length where it is strongest, with changing overlap between actin and myosin filaments affecting strength.
What are the characteristics of fast muscle fibres?
They produce a lot of force quickly but fatigue quickly.
What are the characteristics of slow muscle fibres?
They supply steady force and are slow to tire.
