The sites where the motor nerve impulse is transmitted from the nerve endings to the skeletal muscle cell membranes are the a. neuromuscular junctions, b. sarcomeres, c. myofilaments, d. Z discs.

Video transcript

Hi, everyone. Let's take a look at this practice problem together. What is the function of the fixator muscles? The answer options are a, they oppose or reverse a movement. B they aid the action of prime movers by reducing undesirable or unnecessary movement. C they immobilize the origin of a prime mover so that all the tension is exerted at the insertion and D, they are responsible for producing a particular movement. All right. So muscles can be categorized into broad groups based on the interactions they have in the body. Now, the different types, there's four of them. So let's go ahead and review those categories together. So we have the prime movers, synergist muscles, antagonist muscles and fixator muscles. So let's go through and identify what the function of the fixator muscles are. Is option D. Now this muscle produces a particular movement. This is the function of a prime mover which is also known as agonist muscles. So option D is incorrect. Option A is a muscle that opposes or reverses a movement and that is known as an antagonist muscle. So option A is incorrect as well. Option B A muscle that aids the action of prime movers. This is called a synergist muscle. And that's because they work together with the prime mover muscle in synergy. So this is incorrect as well. The correct answer is option C fixator muscles. We can consider them a type of specialized synergist because they do aid the action of the prime movers. But they go one step further by immobilizing the origin of a prime mover. So the correct answer is option C they immobilize the origin of a prime mover so that all the tension is exerted at the insertion. All right, everyone, I hope you found this helpful and I'll see you soon for the next practice problem.