LW5 Muscular System.pdf

Name_______________________________Year/Section_______________Date___________ Muscular System Laboratory Activity Objectives: At the end of this activity, the students will be able to:  Describe the structure of t...

Name_______________________________Year/Section_______________Date___________ Muscular System Laboratory Activity Objectives: At the end of this activity, the students will be able to:  Describe the structure of the skeletal muscle tissue and skeletal muscle fibers  Identify the connective tissue structures in the skeletal muscle  Describe the structure of the neuromuscular junction  Identify major skeletal muscles and describe their action Skeletal muscles are organs composed of skeletal muscle tissue and connective tissue.Thes organs also contain nerves and blood vessels. The skeletal muscle fibers within skeletal muscles contract (shorten) and cause movement of our skeleton or skin. The signal for contraction is carried by neurons that innervate each skeletal muscle fiber. We consciously control contraction of skeletal muscles, so the contraction is called voluntary. Skeletal muscle fibers (cells) are striated and multinucleated. The striations are light and dark stripes along the muscle cell. A skeletal muscle fiber is actually many embryonic cells that have fused together to form one large cell with multiple nuclei. Each skeletal muscle fiber is stimulated to contract by a motor neuron. A motor neuron and all the skeletal muscle fibers it innervates are a motor unit. Within the muscle, the axon of a motor neuron divides into many branches or axon terminals, each of which forms a neuromuscular junction with a skeletal muscle fiber. There are approximately 700 skeletal muscles in the human body, and most of these originate and/or insert on an area of the skeleton. Because most muscles or their tendons cross a joint, muscle contractions cause skeletal movement at the joint. The action of a muscle is determined by the location of the muscle attachment points, called the origin and insertion. The non-moving component of a muscle is called the origin, and the moveable component is the insertion. When a muscle contracts, the insertion moves toward the origin. A. Skeletal Muscle Tissue and Connective Tissue Coverings. I. Based on the given choices, identify the parts of the skeletal muscles tissue: II. Number the following nestled, cylindrical structures from largest (1) to smallest (5) _____ Myofibril _____ Fascicle _____ Filaments _____ Muscle fiber _____ Muscle B. Skeletal Muscle Fiber I. Based on the given choices, identify the parts of the skeletal muscles fiber: II. Identify the structure that matches the description. ______________________ 1. Connective tissue covering surrounding a fascicle ______________________ 2. Finger-like invaginations of plasma membrane; extend into interior of fiber and surround myofibrils ______________________ 3. Plasma membrane of skeletal muscle fiber ______________________ 4. Connective tissue covering surrounding the muscle ______________________ 5. Smallest contractile unit within individual muscle fibers ______________________ 6. Stores calcium within muscle fiber ______________________ 7. Connective tissue covering surrounding individual muscle fibers ______________________ 8. Two terminal cisternae and a T tubule ______________________ 9. Rod-like structures within skeletal muscle fiber that contain thin and thick filaments organized into sarcomeres C. Neuromuscular Junction I. Based on the given choices, identify the parts of the neuromuscular junction: II. Write the name of the structure(s) described. ______________________ 1. Found in synaptic end bulbs of axon terminal; contains neurotransmitter molecules ______________________ 2. Area of sarcolemma across from synaptic end bulbs of axon terminal; contains neurotransmitter receptors ______________________ 3. Space between synaptic end bulbs of axon terminal and sarcolemma ______________________ 4. Divides into synaptic end bulbs at neuromuscular junction ______________________ 5. Parts of axon terminal that form neuromuscular junction D. Major Skeletal Muscles I. Identify a few of the major skeletal muscles and provide their muscle actions. Muscle Action 1._________________ - ___________________________________________ 2._________________ - ___________________________________________ 3._________________ - ___________________________________________ 4._________________ - ___________________________________________ 5._________________ - ___________________________________________ 6._________________ - ___________________________________________ 7._________________ - ___________________________________________ 8._________________ - ___________________________________________ 9._________________ - ___________________________________________ 10.________________ - ___________________________________________ 11.________________ - ___________________________________________ 12.________________ - ___________________________________________ References: Marieb, E., Keller, S. (2018). Essentials of human anatomy and physiology. (12th ed.). England: Pearson Education Marieb, E., Jackson, P. (2018). Essentials of human anatomy and physiology laboratory manual. (7th ed). Singapore: Pearson Education South Asia Allen, C., Harper, V. (2017). Laboratory Manual for Anatomy and Physiology. (6th ed.). NJ: John Wiley & Sons, Inc.