What causes skeletal muscle relaxation? a) nhibitory interneuron releases gaba onto muscle b) descending neurons from brain directly inhibit muscle fibers c) motor neuron does not fire action potentials e) inhibitory motor neuron releases acetylcholine onto muscle

The correct option is C. Motor neuron does not fire action potentials

Explanation:

During contraction, the motor nerve passes down an action potential. A neuromuscular junction is formed by the motor neuron which stimulates the entry of calcium ions. The calcium ions bind to structures called as troponin which stimulates the binding of the filaments, actin and myosin. The filaments begin to contract by using ATP.

During relaxation, the action potential is stopped. Calcium is taken back into the sarcoplasmic reticulum. As a result, actin and myosin filaments do not link and hence, the contraction is stopped.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.

blah

explanation: bc blah