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BIO 40 A LAB 8.pages Bio 40 A LAB 8: Muscle Histology and Skeletal Muscles (Musculature) Objectives: After successful completion of this Lab activities, the Students should be able to 1. describe the properties of muscle tissues 2. perform activities “muscle fatigue lab” to critically analyze the muscle physiology 3. compare and contrast the three types of muscle tissue 4. demonstrate the structure of the sarcomere 5. identify selected skeletal muscles of the body and 6. relate muscle actions to the origin and insertion Briefly Describe Properties of Muscles: (NOT the functions of muscles) Muscle Fatigue Lab Introduction: Muscle cells rely on aerobic respiration for their energy needs. When muscles are deprived of their customary oxygen, they are capable of functioning but for only a short period of time. During intense or prolonged activity, oxygen is often being used by the body faster than it can be supplied to the muscle. The muscle cells will continue to function. However, they begin to get extra amounts of energy via anaerobic respiration. In anaerobic respiration, the body builds up lactic acid causing muscles to experience fatigue. This reduces the muscle’s ability to function and the body desires rest to build up its oxygen supplies once again. Following a period of the rest the muscle cells regain their normal condition and can function normally once again. Objectives: Students will be able to determine their level of muscle fatigue by performing the “tennis ball exercise” using both hands and evaluating their data to determine any change in muscle performance during sustained exercise. They will also compare performance between right and left hand muscles. *Research QUESTION*: What duration does it take for muscles to become fatigued? Hypothesis: Predict using an if……… then ………. because statement what you believe will happen. *MATERIALS*: * stress ball; stopwatch, graph paper, colored pencils, ruler *PROCESS SKILLS*: * Collecting Data * Analyzing Data * Graphing 1. Hold a stress ball in your dominant hand. Start the timer and start squeezing the ball as fast as you can, and count the number of squeezes. 2. Record the number of times you can squeeze the ball in 10 second intervals over 100 seconds. A qualified squeeze causes a dent in the ball made by using the heel of the hand. Do not stop during the 100 seconds - keep squeezing but collect data for each 10 seconds time frame. It is better if someone can write the counts. NOTE: DO NOT REST between 10 second intervals. 3. Now repeat the procedure for your non-dominant hand and record data. CAUTION: ✓ To prevent injury, stop when the activity can no longer be completed (hand cannot dent the ball). ✓ If you suffer or have suffered from carpal tunnel syndrome or other ailments in your fingers, hands, or wrists, DO NOT PERFORM this exercise. Presentation and Analysis of Data: 1. Graphing - Construct a line graph that displays data (your and partner’s). Include the following: a title, X axis (time in seconds), Y axis (# of squeezes), a key/legend, color for your and partner’s data. 2. Analysis: A. Compare the number of contractions between all ten trials with your dominant hand. Describe the trend. B. Compare the number of contractions between all ten trials with your non-dominant hand. Describe the trend. C. What is muscle fatigue? Describe the physiological basis of muscle fatigue. Partner 1 Partner 2 (optional) Dominant hand Non-dominant hand Dominant hand Non-dominant hand Time (sec) # of Squeezes # of Squeezes # of Squeezes # of Squeezes 0 - 10 11 - 20 21 - 30 31 - 40 41 - 50 51 - 60 61 - 70 71 - 80 81 - 90 91 - 100 TOTAL AVERAGE D. Explain why the body requires a period of rest after intense or prolonged physical activity. Conclusion: Summarize your findings and re-visit your hypothesis. MUSCLE TISSUE Histology: This week we will be examining the three types of muscle tissue that occur: skeletal muscle, cardiac muscle and smooth muscle. Muscles are composed of many muscle cells that are also called muscle fibers. Skeletal and cardiac muscles are classified as striated muscles because their muscle fibers have the appearance of altering light and dark bands under the light microscope. A. Most skeletal muscles are attached to the bones of the skeleton, enabling them to control body movement. Skeletal muscle cells are long, cylindrical, have multiple nuclei and these nuclei are located on the periphery of the cell. Skeletal muscle is striated. They have an alternating pattern of light (I) and dark (A) bands. B. Cardiac muscle is found only in the heart and is responsible for transporting blood through the circulatory system. Cardiac muscle is striated, but its cells are short, (mostly) uninucleate and branched and it has intercalated discs that represents the gap junctions (facilitate coordinated contraction of cardiac muscles). C. Smooth muscle is the primary muscle surrounding internal organs such as the stomach, urinary bladder, and blood vessels. Smooth muscle fibers are spindle shaped. That is they are wide in the middle and narrow to almost pointed at both ends. Smooth muscle cells have a single centrally located nucleus. Smooth muscle cells do not have visible striations although they do contain the same contractile proteins as skeletal and cardiac muscle, these proteins are just laid out in a different pattern. Smooth muscle contracts with less tension, but over a greater range of lengths than skeletal muscle. In addition, it has slow contractions, but with more control over contraction strength than with skeletal muscle. Individually, observe each of the slides (https://web.duke.edu/histology/SlideIndex.html) and draw longitudinal sections of each of the three types of muscle tissue under high power of magnification. Skeletal muscle tissue Cardiac muscle tissue Smooth muscle tissue https://web.duke.edu/histology/SlideIndex.html The diagram labeled A represents muscle myofibril in a simplified manner in a relaxed skeletal muscle. Apply the “key vocabularies”, identify the parts or structures indicated. The diagram labeled B represents muscle myofibril in a simplified manner in a contracted skeletal muscle. Key vocabularies: ___ actin filament ____ myosin filament ____ A band ____ I band ____ sarcomere ____ Z disc Movement by muscles: As we begin our discussion of muscle anatomy it is important to recall knowledge of planes of the body and movement patterns among joints in the body, and various new terminology regarding muscles. To properly identify a muscle, you must identify the muscle’s origin and insertion. The origin of a muscle is the point at which the muscle attaches to a bone (via a tendon) and is static. The insertion of the muscle is the point at which the muscle attaches to a bone (via a tendon) and moves that bone upon contraction. During a contraction, the insertion moves close to the origin. A B D C EF TERMS USED TO NAME MUSCLES CRITERIA WORD ROOT MEANING / Example Name muscles with these roots SIZE Maximus Largest Minimus Smallest Major Larger Minor Smaller Longus Long Brevis Short Vastus Great, Large, Vast Gracilis Slender, Delicate SHAPE Deltoid Triangular Platy Flat Rhomboid 4-sided, opposite sides parallel Serratus Saw-like edge Teres Long and round FIBER ARRANGEMEN T Oblique slanted or angled arrangement Rectus Straight Rectus femoris Transversus Lying across ACTION Adductor Moving a part toward midline Abductor Moving a part away from a midline Flexor Bends a part Extensor Straightens a part Tensor Tightens a part NUMBER OF MUSCLE DIVISION Triceps Three (tri) heads (ceps) Biceps Two (bi) heads (ceps) Digastric Two (di) bellies (gastric) POINT OF ATTACHMENT Sternocleidomastoi d Attached to the sternum (sterno), the clavicle (cleido), and the mastoid process. Sternocleidomastoid LOCATION (Selected Examples) Intercostal Between (inter) the ribs (Costal) Tibialis lower leg region digitorum moves the fingers MUSCLES for IDENTIFICATION: in Figures, Models and on self There are more than 650 skeletal muscles in the human body. We will practice with the following skeletal muscles and will be responsible for the 1. Identification in a figure/diagram/model and our own body (if not directly, then visualizing) 2. Origin of the muscle (bone and bone marking) 3. Insertion of the muscle (bone and bone marking) 4. (Prime mover) Action of the muscle Application of terms like flexion/extension, abduction etc. For some movements, students will be responsible for the synergistic/antagonistic muscles. Identifying Muscles on Yourself You will first need to identify muscles on yourself or fellow students. (This does not require dissection!) Work with a partner to demonstrate the operation of the following muscles. One of you can demonstrate the movement while the other can supply resistance and palpate the muscle being tested. 1. To observe the deltoid, attempt to abduct your arm against resistance. Observe the large triangular muscle that caps the shoulder joint. 2. Now adduct the arm against resistance. You are using the latissimus dorsi. 3. Press your hands together at chest level with your elbows widely abducted. You just used your pectoralis major. 4. Flex your elbow, you will observe the bulging of the contracting biceps brachii muscle. 5. Flex your elbow and then try to extend it against resistance. The muscle used is the triceps brachii. 6. Strongly flex your wrist and make a fist. Palpate your contracting forearm flexor muscles and their tendons