Final answer:
The correct answer to the Oculosympathetic pupillary pathway (sympathetic) is option C) Sympathetic preganglionic arc. This arc allows pupil dilation by traveling from the hypothalamus to the superior cervical ganglion and ultimately leading to the release of norepinephrine onto the radial fibers of the iris.
Step-by-step explanation:
The Oculosympathetic pupillary pathway, which is part of the sympathetic nervous system, plays a crucial role in controlling pupillary size in response to varying light levels. Among the options provided, option C) Sympathetic preganglionic arc - Travels from hypothalamus to superior cervical ganglion is correct. This pathway begins with the hypothalamus and projects through the spinal cord to the superior cervical ganglion. Upon activation, the pathway causes the release of norepinephrine onto the radial fibers of the iris, resulting in pupil dilation which increases the amount of light entering the retina under low light conditions.
The pupillary light reflex is an important homeostatic function of the autonomic nervous system involving both the sympathetic and parasympathetic divisions. The afferent branch of this reflex is the sensory signal triggered by light hitting the retina, which travels along the optic nerve to the brain. The efferent branch can be either the parasympathetic arc, leading to pupil constriction via the release of acetylcholine (ACh) onto circular fibers in the iris, or the sympathetic arc, leading to dilation as described above.