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 |
Procedure
1. Examine the digital slide images of the neuromuscular junction.
| Neuromuscular junction 100X. |
| Neuromuscular Junction (Longitudinal Section) 1000X. |
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.
2. Are there few or many nuclei at the end plate?
3. What is a motor unit?
4. How is a greater force generated (in terms or motor unit recruitment)?
5. What types of sensors are present within the muscle to identify how much force is generated?