Experiment 2 The Neuromuscular Junction Each skeletal muscle is connected to the nervous system be motor end units When the neurotransmitter acetylcholine is release at this site the muscle fiber depolarizes Calcium ions are released from stores in the sarcoplasmic reticulum The presence of Ca2 triggers the ratcheting of actin and myosin filaments and the contraction of the myofiber as all of the myofibrils contract simultaneously Materials Neuromuscular Junction Digital Slide Images Neuromuscular Junction Longitudinal Section Digital Slide Images Post Lab Questions 1 Identify the axon terminal branches and muscle fibers in the slide image below If possible trace the fiber to its terminus 2013 eScience Labs LLC All Rights Reserved 2 Are there few or many nuclei at the end plate There are many nuclei at the end plate 3 What is a motor unit A motor unit is one motor neuron and all the muscle fibers it innervates 4 How is a greater force generated in terms or motor unit recruitment In order to produce a great force one motor nerve can branch into tens or a thousand branches each terminating on a different muscle fiber One single muscle fiber consists of hundreds of motor units The bigger motor units are made up of fast twitch fibers which produce a greater force 5 What types of sensors are present within the muscle to identify how much force is generated In the limbs such as the legs and arms the proprioceptors provide the information about a joint angle the length of a muscle and the muscle tension This tells the position of the limb 2013 eScience Labs LLC All Rights Reserved
View Full Document
Unlocking...