Figure 12-11. Levels of the CNS.
a. Reflex Arc. The simplest and lowest level of control is the reflex arc. The
reflex arc operates essentially on the level of the sensory input.
b. Segmental Reflexes. Segmental reflexes produce a wider reaction to a
stimulus than the reflex arc. For this purpose, the nervous system is organized more
complexly. Thus, information spreads to a wider area of CNS. We can observe a
greater reaction to the stimulus.
12-33. BRAINSTEM "CENTERS"
Within the brainstem, there is a well integrated series of control centers.