Neuromuscular Function and Control of Movement

Question 1

Parts of a Neuron (BE ABLE TO DRAW)

Answer 1

• Axon Hillock (start of action potential)
• Dendrites (Recieve information)
• Nucleus (Processing Center)
• Axon (Send Impulses)
• Myles Sheath (Allow for fast, proper conduction of impulses)

Question 2

Activities at the synapse (NEED TO KNOW!!! FOUNDATION FOR UNDERSTANDING ACTION POTENTIAL)

Answer 2

1) Action Potential proceed to synapse
2) CA2+ enters nerve
3) Vesicles move to membrane
4) Vesicles fuse with membrane
5) ACh released into clef
6) ACh binds receptor on post-synaptic membrane
7) Na+ enters muscle cell
8) Na+ causes depolarization of the post-synaptic membrane

Question 3

Phases of Action Potential

Answer 3

1) Phase 4: Resting Condition (Electrically polarized, membrane potential -90 mV)
2) Phase 0: Depolarization (Opening of fast Na+ channels {influx of Na+}, +20-30 mV)
3) Phase 1: Early rapid repolarization (Fast Na+ channels close and K+ leaks out lowers membrane potential)
4) Phase 2: Plateau phase (“slow repolarization, K+ leaks out, Opening of Ca++ and slow Na+ channels, balances charges inside cell, Cell “electrically dead”)
5) Phase 3: “final rapid repolarization’ (Ca++ and slow Na+ channels close, K+ leaves unopposed, membrane potential resetting)

Question 4

Motor Unit (Give example)

Answer 4

Motor neuron and the muscle fibers it innervates smallest functional unit in muscle (EX: axon’s in spinal cord communicate to muscle)

Question 5

The Neuromuscular junction

Answer 5

Special synapse between branch of a motor neuron and sarcolemma of a muscle fiber