2. The Neuromuscular Junction Chapter 10 Anatomy and Physiology Mr. Knowles Liberty Senior High School

3. Neuromuscular Junction (NMJ) Communication b/w the nervous system & skeletal muscle fiber.

5. Soma

9. Neuromuscular Junction (NMJ) As an axon enters a muscle, it branches into a number of synaptic terminals synaptic terminals, each of which forms a NMJ with a single muscle Fiber.

10. Synaptic Terminal Acetylcholine (ACh).Contains Molecules of Acetylcholine (ACh). AChACh is a neurotransmitter, chemical released by neurons to change the membrane properties of other cells.

11. Synaptic Cleft narrow spaceA narrow space that separates the synaptic terminal of the neuron from the sarcolemma surface. (AChE) AchContains Acetylcholinesterase (AChE) which breaks down Ach.

14. Motor End Plate ACh.The surface of the sarcolemma that contains membrane receptors that bind ACh.

16. When a neuron stimulates a muscle fiber, Heeeeere’s what happens...

17. The arrival of an action potential Sudden change in the transmembrane potential along the axon. AChThis stimulates the release of ACh at the synaptic terminal.

19. The release of ACh ACh,Vesicles that contain ACh, in the synaptic terminal, fuse with the membrane of the neuron & are released by exocytosis into the synaptic cleft.

20. ACh binding at the motor end plate ACh ACh receptorsACh molecules diffuse across the synaptic cleft & bind to ACh receptors on the motor end plate’s surface. ACh (Na + )When ACh binding occurs, sodium ions (Na + ) now can rush into the sarcoplasm.

21. Appearance of an action potential in the sarcolemma Na +The Na + results in an action potential in the sarcolemma. T tubules Ca 2+ terminal cisternae.The action potential sweeps across the entire membrane surface & travels down each of the T tubules which triggers the release of Ca 2+ at the terminal cisternae. AChE ACh.While this is occurring, AChE removes the ACh.

22. Return to the initial state ACh AChEEven before the action potential has spread across the entire membrane, the ACh has been broken down by AChE. This sequence of events can now be repeated, should another AP arrive at the synaptic terminal

23. Normal

25. Show me the action! Potential, that is!

26. What happens at the neuromuscular junction when exposed to botulinum toxin?

27. Effects of a Nerve Agent

28. Atropine Antidote

29. What is myasthenia gravis?