The term autonomic nervous system (ANS) refers to collections of motor neurons (ganglia) situated in the head, neck, thorax, abdomen, and pelvis, and to the axonal connections of these neurons (Figure 1).rain and spinal cord pathways regulating autonomic outflow. Preganglionic neurons for parasympathetic and sympathetic autonomic outflow are located in the brainstem and in thoracic, upper lumbar and sacral regions of the spinal cord (Figure 1). Several different brain centres control these preganglionic neurons.
A: Moon phases are caused by the motions of the Earth and moon as they relate to the sun. Phases occur as the Earth-facing side of the moon changes over the course of 29.5 days when the moon revolves around the planet. When the angle of sunlight reflecting off the moon changes, humans observe different lighting levels from the moon.
The phase of the Moon can tell you the time of day. For example, because a full Moon is seen when the Moon is on the opposite side of the Earth from the Sun, an observer on the Earth will see the Moon rise just as the Sun sets.n other words, the amount of the Moon that we can see changes over time in a cyclic period that repeats itself approximately once a month. (The actual period of this cycle is approximately 29.5 Earth days.) The cause of these phases is the relative positions of the Sun, Earth, and Moon.