The major muscle involved in as action is called the _
A protagonist
B synergist
C fixator
D prime mover
E antagonist
The correct answer and explanation is:
The correct answer is D. Prime mover.
In human anatomy, muscles work together in a coordinated manner to produce movement. The prime mover, also known as the agonist, is the muscle that is primarily responsible for initiating and carrying out a specific action. For example, when you perform a bicep curl, the biceps brachii is the prime mover as it is the muscle mainly responsible for flexing the arm.
Muscles do not work in isolation; they often rely on other muscles to support the movement. These muscles can be classified into several types, including:
- Synergists: These muscles assist the prime mover by contributing additional force or by reducing unwanted movement. For instance, in the bicep curl, the brachialis muscle acts as a synergist to help the biceps lift the weight.
- Antagonists: These muscles oppose the action of the prime mover. For example, when the biceps contract to flex the arm, the triceps brachii is the antagonist as it works to extend the arm. Antagonists provide balance and control, ensuring that movement does not occur too quickly or forcefully.
- Fixators: These muscles stabilize a joint or body part so that the prime mover can function more effectively. In the case of a bicep curl, muscles in the shoulder, like the rotator cuff, act as fixators to prevent the shoulder from moving during the exercise.
Therefore, the prime mover is the muscle primarily responsible for a particular action, while synergists, antagonists, and fixators support or counterbalance the movement in different ways.