Muscle Contraction Steps
What neurotransmitter is released at the neuromuscular junction to start muscle contraction?
acetylcholine (ACh)
The main muscle responsible for movement is called the ______.
Prime moved (agonist)
What does the term “rectus” mean in a muscle name?
straight fibers
Bones act as _______, and joints act as _______.
levers and fulcrums
What muscle is the prime mover of inspiration?
Diaphram
In which step are calcium ions released from the sarcoplasmic reticulum?
What is excitation–contraction coupling?
What muscle opposes or reverses the movement of a prime mover?
antagonist
A muscle named “biceps” has how many origins?
two
Which lever class gives the most mechanical strength advantage?
second-class lever
What muscle group is primarily responsible for chewing?
masseter and temporalis
What happens when calcium binds to troponin?
It moves tropomyosin, exposing actin binding sites for myosin heads.
Which muscle acts as the prime mover for flexing the forearm?
biceps brachii
What does “oblique” indicate about a muscle’s fibers?
They run at an angle
Which lever class provides the greatest speed and range of motion?
third-class lever
Which muscle group helps maintain posture?
erector spinae
What two things happen during the relaxation phase of muscle contraction?
Acetylcholine is broken down, and calcium is pumped back into the sarcoplasmic reticulum.
Name the antagonist to the biceps brachii
triceps brachii
What does “longus” indicate in a muscle name?
long
What real-life movement is an example of a first-class lever?
Lifting your head off your chest
Why are abdominal muscles arranged in layers with different fiber directions?
To increase strength and allow movement in multiple directions
What structure carries the action potential deep into the muscle fiber?
T-tubules
What is the role of a fixator muscle during movement?
It stabilizes the origin of the prime mover.
Which naming term means “largest”?
maximus
In a lever system, what provides the effort?
muscle contraction?
Why is the rotator cuff group important for shoulder stability?
They reinforce the joint capsule and prevent dislocation of the humerus.