The control of movement is often divided into mechanisms of reflexes and of voluntary movement.
What is a reflex? It is a stereotyped, automatic movement evoked by a specific stimulus. It is uniform across members of a species. Some examples in humans are the patellar or kneejerk reflex, the salivary reflex, the orienting reflex, and the pupillary reflex.
In reviewing the reflex arc, pay special attention to proprioception, muscle spindles, the stretch reflex, and primary motor cortex.
Further, let’s think about the cycles in our behavior. They are ancient and varied. We certainly inherited them from species that evolved earlier than we did.
We harbor a number of rhythms. Generally we have cellular cycles that augment the day-night rhythm to regulate our behavioral cycles. There are possibly very long cycles that govern our evolution. Men and women both run on cycles, though with differences. But do our cycles still make biological sense?