T7 - Muscular System Student

CC2417 Human Biology

Chapter 7 -Muscular system Tutorial Part I On-line learning Activities 1. Click to the following link and do the on-line quiz http://highered.mcgraw-hill.com/classware/ala.do?alaid=ala_1259063 Breakdown of ATP and Cross-Bridge Movement During Muscle Contraction Energy Sources for Prolonged Exercise Function of the Neuromuscular Junction Function of the Neuromuscular Junction (Quiz 2) Function of the Neuromuscular Junction (Quiz 3) Myofilament Contraction Sarcomere Contraction

2. Identify superficial muscles Refer to the below websites and identify the superficial muscles a. http://www.gwc.maricopa.edu/class/bio201/muscle/mustut.htm • Facial and masticatory muscles - Masseter; Tamporalis • Neck – Trapesius; Sternocleidomastoid • Posterior trunk- Teres major, Teres minor: Infraspinatus; Latissimus dorsi; Erector spinae; Levator scapulae; • Anterior trunk and abdomen- Pectoralis major; Pectoralis minor; Seratus anterior; External obligue; Internal obligue; Rectus abdominis; Transverses abdominis • Upper limbs- Deltoid; Biceps brachii; Triceps brachii • Lower limbs – Hamstring group of muscle; Gluteus maximus; Rectus femoris; vastus lateralis Part II True/ False Questions and Fills in the blanks 1. Endomysium separates individual muscle fibers. 2. A motor neuron and the muscle fibers that it controls constitute a motor unit. 3. During muscle contraction, calcium ions combine with tropomyosin, and this exposes active sites for cross-bridge formation. 4. The enzyme ATPase occurs in the globular portion of myosin molecules. 5. The anaerobic phase of respiration occurs primarily in mitochondria. 6. Liver cells convert lactic acid to ATP. 7. The minimal strength of stimulation needed to elicit a muscle contraction is called the threshold stimulus. 8. The latent period is the time when the muscle is relaxed. 9. White muscles have an increased capacity to carry on aerobic respiration.

Prepared by Wendy Chan in Nov09 -1-

CC2417 Human Biology 10. Only about 25% of the energy released by cellular respiration is available for use by metabolic processes. 11. Muscle fatigue is most likely due to an accumulation of ______ ______. 12. A neurotransmitter substance crosses the synaptic cleft between a nerve and muscle fiber, and stimulates the nerve to have an action potential. 13. Motor unit recruitment refers to the fact that some motor neurons can recruit new skeletal muscle fibers with which they connect. 14. The staircase effect (treppe) is a condition in which an inactive skeletal muscle is subjected to a series of stimuli and the strength of each successive contraction increases until a maximum is reached. 15. The pigment responsible for the reddish brown color of skeletal muscle is called ______. 16. During anaerobic respiration, glucose molecules are converted into molecules of ______ ______. 17. A forceful, sustained muscle contraction is called a ______ ______. 18. In order to stimulate skeletal muscle fibers, motor neurons release the neurotransmitter ______. 19. The rhythmic, wavelike motion produced by smooth muscles in tubular visceral organs is called _______. 20. Muscles that assist a prime mover are called ______. 21. The combining of a series of twitches to produce a sustained contraction is called ______. 22. The ______ ______ at the ends of cardiac muscle cells help to hold adjacent cells together. Part III. Do learning Objective Questions on Maders’ (TB) page 179-180. Part IV Review Exercises 6. Describe a neuromuscular junction. 12. Describe how an oxygen debt may develop. 13. Explain how muscles may become fatigued and how a person’s physical condition may affect tolerance to fatigue. 19. Explain how a skeletal muscle can be stimulated to produce a sustained contraction. Part V. Critical Thinking Questions Why do you think athletes generally perform better if they warm up by exercising lightly before a competitive event? Prepared by Wendy Chan in Nov09 -2-