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 lunar phase or phase of the Moon is the shape of the directly sunlit portion of the Moon as viewed from Earth. The lunar phases gradually and cyclically change over the period of a synodic month, as the orbital positions of the Moon around Earth and of Earth around the Sun shift. The Moon's rotation is tidally locked by Earth's gravity; therefore, most of the same lunar side always faces Earth. This near side is variously sunlit, depending on the position of the Moon in its orbit. Thus, the