Question

For relaxation to occur,______

O ach receptors close and ca channels on the sarcoplasmic reticulum open.

O ach receptors open and ca channels on the sarcoplasmic reticulum open.

O ach receptors open and ca channels on the sarcoplasmic reticulum close.

O ach receptors close and ca channels on the sarcoplasmic reticulum close.

Answer 1

For relaxation to occur, ACh receptors close and Ca channels on the sarcoplasmic reticulum close.

Step-by-step explanation:

To achieve relaxation, ACh receptors close and Ca channels on the sarcoplasmic reticulum close. When the motor neuron stops releasing ACh into the synapse, the muscle fiber repolarizes, leading to the closure of gates in the sarcoplasmic reticulum where Ca was being released.

ATP-driven pumps then move Ca out of the sarcoplasm and back into the sarcoplasmic reticulum, resulting in the 'reshielding' of the actin-binding sites on the thin filaments, preventing the formation of cross-bridges between the thin and thick filaments and leading to muscle relaxation. As a result, option O acetylcholine receptors close and Ca channels on the sarcoplasmic reticulum close.