text: Physiology
  as a range safety. If the Soldier cannot recover properly from the acute training load (the Squat), then the
  training load will accumulate and not be absorbed. The continued volume and intensity of the workload
  becomes chronic. This failure to properly progress the workload increases risk of underperformance and
  tissue damage.
  CENTRAL NERVOUS SYSTEM
  4-30. The right and left halves of the brain, called hemispheres, are divided into lobes. The lobes form an
  integrated system that supports all conscious and unconscious functions. The following descriptions of each
  lobe impact these Soldier function:
  * Frontal lobe contains the premotor cortex and motor cortex, which are the areas that plan and
  perform movements and contains the Broca’s area for speech production.
  * Parietal lobe processes sensory information, sensory discrimination, and body orientation.
  * Occipital lobe processes signals for visual reception and interpretation.
  * Cerebellum coordinates of voluntary movement, to include walking in a straight line.
  * Brain stem controls breathing, digestion, heart control, blood vessel control, and alertness.
  * Temporal lobe processes auditory reception, expressed behavior, receptive speech, and memory
  information retrieval; it contains Wernicke’s area for speech comprehension.
  4-31. The size and anatomy of the adult brain is fully developed by age 26. However, this does not mean
  that learning ceases. When awake, people are constantly learning. The 12 pairs of peripheral nerves that
  branch directly from the brain but remain largely inside the skull are called cranial nerves. They innervate
  (such as supply with nerves) the muscles and sensory organs of the face and head. The sensory input that the
  cranial nerves transmit to the brain during daily activities and training become memory. Most of the
  information about these activities becomes short-term memory, stored for a few seconds to allow
  understanding of immediate or near-term events and then discarded.
  4-32. A fair amount of information is stored as long-term memory. Storage is particularly efficient after
  sleeping for more than 6 hours the night after the event. These memories last for a few minutes or as far into
  the past as it is possible to remember allowing the conscious recall of episodes and facts. Other memories
  (sometimes called skills) help with the repetition of tasks performed subconsciously such as walking, eating,
  and driving. Fundamental physical training develops fundamental Soldier skills—move, shoot,
  communicate, survive, and protect or treat—and the long-term memories to support them. Soldiers who have
  highly developed motor skills will have very extensive “neural wiring” in their brains related to those
  activities. In the well-trained Soldier, particularly the ones who practice the fundamentals, the motions and
  continual decision making needed to perform these combat functions happen without conscious awareness.
  4-33. Deep in the two lobes of the brain sits the limbic system. This collective term for the structures near
  the middle of the brain includes the hippocampus and amygdala. This connection allows the limbic system
  to impact the endocrine and autonomic motor systems. The limbic system may affect motivation and mood.
  4-34. The spinal cord is the other major anatomical part of the central nervous system. This thick bundle of
  nerve fibers connects the brain to the peripheral nerves. It originates in the brain stem and ends in the lumbar
  spine, protected by the vertebrae.
  PERIPHERAL NERVOUS SYSTEM
  4-35. At each level of the spine, smaller bundles of nerve fibers split off to form the peripheral nervous
  system. After leaving the spine, the peripheral nerves split and re-form into major nerves such as the median
  and radial nerve in the arms and the sciatic and femoral nerves in the legs. The peripheral nerves branch into
  progressively smaller bundles until a single nerve fiber meets with the part of the body it innervates. If the
  nerve supplies a muscle cell it is a motor neuron. Where the nerve ending meets the muscle, the connection
  or synapse is called a neuromuscular junction (known as an NMJ). The types and size of the chemical
  reactions that occur at the junction drive the amount of force the muscle can generate.
  4-36. The peripheral nerves originating in the neck (cervical spine) supply sensation and muscle control to
  the shoulders, arms, and hands. The largest of these upper extremity nerves are the median, radial, and ulnar
  nerves. The nerves that supply sensation and muscle control to the legs originate in the lower back. The