Chapter 11: The Muscular System Read pages 325 to 399 NAME Topic Outline And Objectives: A. How skeletal muscles produce movement, and naming muscles 1. Describe the relationship between bones and skeletal muscles in producing body movements. 2. Define a lever and a fulcrum and compare the types of levers on the basis of placement of the fulcrum, effort, and resistance. 3. Identify the various arrangements of fascicular bundles (muscle fibers) in a skeletal muscle and relate the arrangements to the strength of contraction and range of movement (ROM). 4. Discuss most body movements as activities of groups of muscles by explaining the roles of the prime mover, antagonist, synergist, and fixators. B. How skeletal muscles are named 5. Define the criteria employed in naming skeletal muscles. C. Types of body movements produced by muscles 6. Identify body movements as flexion, extension, abduction, and adduction. D. Disorders; Intramuscular (IM) injections; running injuries, and injury prevention 7. Discuss the administration of drugs by intramuscular (MI) injections. 8. Describe several injuries related to running. 9. Describe several ways to prevent injuries during exercise. A. How skeletal muscles produce movement (pages 326 331) A1. What structures or tissues constitute the muscular system? Figure 11-1: The lever-fulcrum principle is illustrated by flexion of the forearm. A2. Refer to Figure 11-1 and consider flexion of your forearm as you do this learning activity. a. In flexion your forearm serves as a rigid rod, or, which moves about a fixed point, called a (your elbow joint, in this case). A2. Continued 1
b. Hold a weight in your hand as you flex your forearm. The weight plus your forearm serve as the (effort? fulcrum? resistance ) during this movement. c. The effort to move this resistance(load) is provided by contraction of a. Note: that if you hold a heavy telephone book in your hand while your forearm is flexed, much more ( effort? fulcrum? resistance ) by your arm muscles would be required. d. In Figure 11-1 identify the exact point at which the muscle causing flexion attaches to the forearm. It is the ( proximal? distal? ) end of the ( humerus? radius? ulna?). Write an E and an I on the two lines next to the arrow at that point in the figure. This indicates that this is the site where the muscle exerts its effort (E) in the lever system, and it is also the insertion (I) end of the muscle. e. Each skeletal muscle is attached to at least two bones. As the muscle shortens, one bone stays in place and so is called the ( origin? insertion?) end of the muscle. f. Name the bone in Figure 11-1 which serves as the origin bone? And, label this as origin (O). g. Now label the remaining arrows in Figure 11-1: (F) at the fulcrum and (R) at resistance. A3. Check your understanding of lever systems in the body. See Figure 11.2, page 328 for help! a. Mechanical advantage (leverage) means that a ( more? less? ) forceful effort can move ( more? less? ) forceful load. Mechanical advantage is providing by having the load always ( closer to? farther from? ) the fulcrum. b. Now, hyperextend your head as if to look at the sky (see Figure 11.2a, page 328 in your text). The weight of your face and jaw serves as the ( E?, F?, R? ), while your neck muscles provide ( E?, F?, R? ). The fulcrum is the joint between the and the bones. A4. Four fascicle arrangements are shown in Figure 11-2 (next page); these same arrangements are described below. First, correctly identify each fascicle arrangement by: (1) writing the appropriate term in the answer blank. (2) writing the letter of the corresponding diagram below. Second, on the remaining lines beside the diagrams, name two muscles that have the fascicle arrangement shown. ; 1. Fascicles insert into a midline tendon from both sides. ; ; ; 2. Muscle fibers are arranged in concentric array around an opening. 3. Fascicles run with the long axis of the muscle. 4. Fascicles angle from a broad origin to a narrow insertion. 2
Figure 11-2 A5. Correlate fascicular arrangement with muscle power(strength) and range of motion(rom) of muscles. a. A muscle with (many? long?) fibers will tend to have great strength. An example is the ( parallel? pennate? ) arrangement. b. A muscle with ( many? long? ) fibers will tend to have great range of motion (ROM). An example is the (parallel? pennate?) arrangement. A6. Refer to Figure 11-1 and do this exercise about how muscles of the body work in groups. a. The muscle that contracts to cause flexion of the forearm is called a -mover. An example of a prime mover in this action would be the muscle. b. The triceps brachii must relax as the biceps brachii flexes the forearm. The triceps is an extensor. Since its action is opposite to that of the biceps the triceps is called ( a synergist? an agonist? an antagonist?) of the biceps. c. What action would occur if the flexors of your forearm were functional, but not the antagonistic extensors? d. What action would occur if both the flexors and extensors contracted simultaneously? e. Muscles that assist or cooperate with the prime mover to cause given action are known as, whereas muscles that stabilize a bone (such as the scapula) so that prime movers and synergists can move another bone ( such as the humerus) are called. 3
B. Naming skeletal muscles (pages 331-333) B1. Review the wordbyte section below. Match the names of the following muscles with their meanings. A. Large muscle of the buttock region B. Belly-shaped muscle in leg C. Thigh muscle with four regions D. The broadcast muscle of the back E. Large muscle in medial thigh area F. Muscle that raises the upper lip G. Muscle in the abdominal region H. Large muscle of the chest Latissimus dorsi Vastus medialis Gluteus maximus Pectoralis major Quadriceps femoris Gastrocnemius Levator labii superioris Transverse abdominis B2. As you study the names of muscles, you will find that most of them provide a good description of the muscle. For each of the following, indicate the type of clue that each part of the names gives. The first one is done for you. In most cases, you will pick more than one characteristic for each. A. Action N. Number of heads or origins D. Direction of fibers P. Location of origin and insertion L. Location of the muscle S. Relative muscle size or shape DL a. Rectus abdominis g. Sternocleidomastoid b. Flexor carpi ulnaris c. Biceps brachii d. Orbicularis oculi e. Zygomaticus minor f. Trapezius h. Adductor longus i. Quadriceps femoris j. Levator scapulae k. Extensor digitorum radialis l. Extensor carpi radialis longus C. Types of body movements produced by muscles (see Chapter 9, pages 265 268) C1. Identify the kinds of movement shown in Figures 11-3 on the next page. Write the name of the movement below each figure. Use the following terms: abduction, adduction, extension, flexion, and hyperextension. Note: refer to chapter 9, pages 265 268 for help. Other movements to know are pronation, supination, medial rotation, lateral rotation, lateral flexion, dorsi flexion, and plantar flexion. 4
Figures 11-3 for C1: 5
of lower leg of vertebral column of lower leg of vertebral column 6
D. Disorders; Intramuscular (IM) injections; running injuries, and injury prevention D1. Complete this exercise on Intramuscular (IM) injections (See page 330 for help) a. State three reasons why intramuscular (IM) injections may be the method of choice for administration of drugs. b. A clinical challenge. Why is the gluteus medius considered a safer site for intramuscular injections than the gluteus maximus? c. Two other muscles commonly used for intramuscular injections are the in the lower extremity and the in the upper extremity. D2. Answer these questions about running injuries. (Pages 391, and 399 for help) a. The most common site of injury for runners is the ( calcaneal tendon? groin? hip? knee? ). b. Patellofemoral stress syndrome is a technical term for. Briefly describe this problem. c. Shinsplint syndrome refers to soreness along the ( patella? tibia? fibula? ). Give an explanation for the soreness. d. Give two suggestions you might make to a beginning runner to help avoid runners injuries, or give a tip of your own that may prevent sports injuries. e. Most sports injuries should be treated initially with RICE therapy for 2-3 days. Specifically, what does the acronym RICE stand for? D3. Give three suggestions you might make to someone who is just beginning an exercise program for the first time to help them avoid any injuries. *Briefly support your suggestions! D4. Give four benefits of stretching. (See page 330 for help). D5. Contrast a strain and a sprain by writing an example sentence for each term. Be sure to give the tissue type involved. (See page 263 for help). 7