Answer:
The eye's arc reflex to changes in light intensity is called photomotor reflex. whose pathway includes: a receptor in cells of the retina, an afferent pathway -Optic nerve-, reception and processing center in Pretectal nucleus and efferent pathway given by oculomotor nerve and short ciliary nerves, whose efector is Pupil constricting muscles.
Explanation:
The reflex arch of the eye is what allows the pupil to close or open -by contracting or relaxing of pupil constrictor muscle, respectively- in response to changes in light intensity. This reflex has a direct pathway for each eye, and a cross pathway (consensual reflex) that stimulates the opposite eye.
The photomotor reflex -reflex arc- pathway is:
- Receptor: photoreceptor cells in the retina.
- Afferent pathway: Optic nerve
- Reception and processing center: Pretectal nucleus of the Midbrain.
- Efferent pathway: Parasympathetic nuclei of the oculomotor nerve → neurons of the ciliary ganglion → short ciliary nerves.
- Effector: Pupil constricting muscles.
The response will be a contraction of the constrictor muscle -pupil closure or myosis- in bright light, and a relaxation -pupil opening or midiriasis- in dark environments.
