If the membrane potential of an axon reaches threshold, then an action potential will occur. If it does not reach threshold, the action potential will not occur. What is this principle called?

Short Answer Section (4 points each): Six questions are listed below, each worth 4 points. For full credit, you must answer five of the questions. If you choose to answer all six, you will be given bonus points. Partial credit will be given for each question. 1. Briefly describe the process of mastication. Be sure to include the correct names of the 4 muscles (that we discussed) involved in mastication, as well as how the function of each bone contributes to the process of chewing.   2. First, pick one muscle that moves the scapula and pectoral girdle. Then, describe its origin, insertion, and one important function of the muscle.   3. First, pick one muscle of the posterior thigh and leg. Then, describe its origin, insertion, and one important function of the muscle.   4. Briefly describe the important steps of an action potential.   5. Describe the structure of a sarcomere at rest. Be sure to include terms such as Z discs, I band, A band, H zone, zone of overlap, and which of these parts creates striations.   6. Briefly describe the important steps of the contraction phase during skeletal muscle contraction.

The latissimus dorsi is a large back muscle that originates from the iliac crest, thoracic vertebrae, and lumbar vertebrae. It inserts as a tendon into the proximal humerus. Which of the following are functions of the latissimus dorsi?

Are nerves in the PNS capable of some regeneration after injury?

The deltoid muscle is the primary “shoulder” muscle that originates from three different locations. The central deltoid originates from the acromion of the scapula. What is the primary function of the central deltoid?

What is the correct term for the functional unit of contraction within a myofibril that extends from Z disc to Z disc?

True or False: The neuromuscular junction (NMJ) is the synapse between a motor neuron and a skeletal muscle fiber.

What is the correct term for the plasma membrane of a muscle cell?

Which of the following muscles originates from the first nine ribs and inserts into the scapula? Its primary functions are protraction of the scapula (pushing forward) and superior rotation of the scapula (over the head). It is also known as the “boxer’s muscle” because it allows for the movement of punching.

Which of the following is the correct term for the extracellular matrix (ECM) of a muscle fiber?