Flashcards in Phys - Skeletal Muscle Deck (20):
Which regions shorten during contraction?
H zone (disappears)
Binds troponin complex to tropomyosin
Binds myosin to actin
Binding site for Ca++
Connects Z line to M line
Acts as a spring, contributes to elasticity of muscle
Scaffolding for myofibrils
Associated with transmembrane sarcoglycans
Skeletal muscle resting Em
Action potentials of skeletal muscles
What is released?
Acetylcholine is released
1. Actin binding
2. Power stroke
3. ATP binding and cross bridge detachment
4. ATP hydrolysis
What happens to the cross bridges?
They do not detach
What happens if Ca++ transported into the SR is inhibited?
The muscle remains contracted
What causes the myosin head to "re-cock"?
ATP hydrolysis to ADP and Pi
The velocity of muscle shortening is inversely related to the ___
No external shortening
Velocity = 0
The load exceeds the ability to create tension
Single contractile event
The load is less than the ability to create tension
Contraction with external lengthening
Example: going down stairs
What is a motor unit?
A single alpha motor neuron and all the muscle fibers it innervates
Motor neurons and muscle fibers are recruited from ___ to ____
Smallest to largest
*this permits development of smooth, graded increases in muscle tension