Question

(9/25/25) formative assessment assignment: chapter 6 the muscular system part 1 (suggested 12 of 16)
now that we have described the structure of the neuromuscular junction, refer to the numbered steps in figure 8 5 as we examine what happens there. when a nerve ( 1 ) reaches the axon terminals, calcium channels open, and calcium (ca2+) enters the terminal. calcium entry causes some of the synaptic vesicles in the axon terminal to fuse with the cell membrane and release acetylcholine, which then ( 2 ) across the synaptic cleft and attaches to membrane receptors in highly folded regions of the sarcolemma. if enough acetylcholine is released, the sarcolemma at that point becomes temporarily even more ( 3 ) to sodium ions (na+), which rush into the muscle fiber, and to potassium ions (k+), which diffuse out of the muscle fiber. however, more na+ enters than k+ leaves. this imbalance gives the cell interior an excess of positive ions, which reverses the resting electrical conditions of the sarcolemma. this event, called ( 4 ), opens more channels that only allow na+ entry. this movement of ions generates an electrical current called an action potential. once begun, the action potential is unstoppable, it travels over the entire surface of the sarcolemma, conducting the ( 5 ) impulse from one end of the cell to the other. the result is contraction of the muscle fiber.
o 1 diffuses 2 permeable 3 depolarization 4 electrical 5 impulse
o 1 impulse 2 diffuses 3 permeable 4 depolarization 5 electrical
o 1 electrical 2 impulse 3 diffuses 4 permeable 5 depolarization
o 1 depolarization 2 electrical 3 impulse 4 diffuses 5 permeable
o 1 permeable 2 depolarization 3 electrical 4 impulse 5 diffuses

Explanation:

When a nerve impulse (1) reaches the axon terminals, processes occur. Acetyl - choline diffuses (2) across the synaptic cleft. The sarcolemma becomes more permeable (3) to certain ions. Depolarization (4) is the event that changes the electrical state. And the action potential conducts the electrical (5) impulse.

Answer:

1. impulse 2. diffuses 3. permeable 4. depolarization 5. electrical