Final answer:
The 3rd-order neuron of the hypothalamospinal tract carries sympathetics to the eyelids, pupil, and skin of the face.
Step-by-step explanation:
The 3rd-order neuron of the hypothalamospinal tract carries sympathetics to the eyelids, pupil, and skin of the face.
The hypothalamus uses visual system input to drive pupillary reflexes. If the retina is activated by high levels of light, the hypothalamus stimulates the parasympathetic response. If the optic nerve message shows low levels of light, the hypothalamus activates the sympathetic response. Output from the hypothalamus can influence the Edinger-Westphal nucleus of the oculomotor complex or the lateral horns of the thoracic spinal cord, which control the size of the pupil and the skin of the face.