n the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlappying of actin and .

In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlappying of actin and myosin.

Explanation:

Sliding filament theory explains the way muscles contract; each sarcomere (functional unit of muscle) contains superimposed thin (actin) and thick (myosin) filaments that are interconnected by cross bridges. According to the theory, the shortening of the length of a sarcomere is produced by the two types of filaments that slide over each other; large intermolecular forces between the myosin head and the crossed bridge cause the head to tilt. Through this power glide, the fine filaments are drawn between the thick filaments of each sarcomere. The contraction is triggered by a stimulating nerve impulse that causes an action potential to spread through the sarcomere.

b - the respond is innate and varies over time.

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after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .