Chapter 10: More on the Muscle system!

This week we are discussing chapter 10 goes into greater detail about the muscles as an organ.  Muscles have four functional groups: prime movers, antagonist, synergists, and fixators.  The prime movers are also known as agonists and provide the major force for creating muscle contractions. The antagonist opposes a particular movement. The synergists add force to a movement and also reduce undesirable or unnecessary movement.  Lastly, the fixators are synergists that immobilize a bone or also the muscle’s origin. An example of these functions would be flexion of the arm. In this scenario, the bicep brachii would be the prime mover or agonist and the tricep brachii would be the antagonist.

Also, there are several types of arrangements that muscles can be in which make them function in different ways. First, parallel are fascicles that run parallel to the long axis of the muscle, a good example of this is the Sartorius which is one of the main muscles of the quadriceps.  Then we have the fusiform, which is spindle-shaped muscle, an example of this type of muscle would be the biceps brachii. The pennate arrangement are short fascicles that attach diagonally to the central tendon running through the length of that muscle, an example of this would be the rectus femoris, also found in the quadriceps.  Next, convergent are when the fascicles converge from a broad origin to a single tendon insertion; this looks like the pectoralis major muscles. Lastly, the circular arrangements are when the fascicles are arranged in rings, such is the muscle around your mouth called the orbicularis oris.

The majority of chapter 10 has a ton of diagrams of the muscles and their names. For the test, try and focus on not only where they are located, but also their function because there will be a little description in the exam question that might give away the muscle even if you don’t know exactly what the diagram is pointing to. Also, remember muscles and their agonist and antagonists. Another helpful study tip for this section is flex or extend the muscle being discussed so you can know the movement and an idea of where the location is on you actual body. These tips helped me for studying for the exam so I hope that it helps you! Check back next week for more study tips!

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