Contraction of skeletal muscle

Cards (13)

How do skeletal muscles move?
In antagonistic pairs
What does antagonistic pairs mean?
When one is contracted the other is relaxed
What is the sliding filament mechanism?
The contraction of the myosin and actin filaments sliding past each other
What changes to the sarcomere to support the sliding filament mechanism?
Z lines move closer
I band and H zone narrows
A band does not change
How are muscles stimulated?
Via synaptic transmission
What does tropomyosin do?
Prevents the myosin head from attaching to the binding site on the actin molecule
What do calcium ions do?
They are released from the sarcoplasmic reticulum, and cause tropomyosin to pull away from the actin molecule
Where does the myosin head bind to?
The actin filament
What causes the actin to move along?
The myosin head changes shape after binding to it
This releases ADP
What does ATP do in muscle contraction?
Fixed to the myosin head, so it detaches from the filament
What does ATP hydrolysis do in muscle contraction?
Provides energy for the myosin head to move back to where it came from
Where does the myosin head reattach?
A binding site further along the actin filament
How do muscles relax?
Calcium ions are actively transported to the sarcoplasmic reticulum, allowing tropomyosin to block the actin, so the mrelaxes