Chapter 12 Flashcards
What happens at the neuromuscular junction?
Acetylcholine activates nicotinic receptors (opening chemically-gated channels on the sarcolemma)leading to sodium influx
What is triggered due to the less negative membrane potential?
- Voltage-gated Na+ channels opened
2. Action potentials spread along sarcolemma
When the muscle cell is at rest where is the highest concentration of calcium in the muscle cell
Sarcoplasmic reticulum
What kind of gate is the DHP receptor associated with
Voltage-gated calcium channel
What kind of gate is the ryanodine channel on the sarcoplasmic reticulum
Mechanically gated calcium channel
What does calcium bind to in order to allow for cross bridges to occur
Troponin
This moves tropomyosin out of the way
What blocks the binding sites on actin
Tropomyosin
What does the H zone contain
Only myosin
What does the I band contain
Only actin
What does the A band contain
All of the myosin
Can be overlap with actin
What causes the myosin head to be cocked
ATP is broken down into ADP and Pi
What happens when ATP binds to mysoin
Actin and myosin dissociate
What causes the power stroke
Pi is released
What are the two types of muscle contractions
Isometric
Isotonic
At what velocity does the greatest load occur
Lowest velocity
