What is pupillary pathway?
Pathway: Afferent pupillary fibers start at the retinal ganglion cell layer and then travel through the optic nerve, optic chiasm, and optic tract, join the brachium of the superior colliculus, and travel to the pretectal area of the midbrain, which sends fibers bilaterally to the efferent Edinger-Westphal nuclei of …
What are the five basic components of the pupillary light reflex pathway?
retina, optic nerve, optic chiasm, and the optic tract fibers that join the ; brachium of the superior colliculus, which terminate in the ; pretectal area of the midbrain, which sends most of its axons bilaterally in the posterior commissure to terminate in the The cause might be that different components of the …
How does the pupillary light reflex work?
The pupillary light reflex pathway. The pupils normally dilate (increase in size) when it is dark (i.e., when light is removed). This response involves the relaxation of the iris sphincter and contraction of the iris dilator. The iris dilator is controlled by the sympathetic nervous system.
What is the pupillary reflex quizlet?
pupillary light reflex. the reduction of pupil size in response to light.
What type of reflex is the pupillary reflex?
light reflex
Pupillary reflexes involve the autonomic (Edinger-Westphal) component of the oculomotor nucleus. In the light reflex, the pupils constrict when light is shone on the retina. If one eye only is stimulated, both pupils constrict, the so-called consensual reflex.
Is pupil dilation a reflex?
Pupillary reflex is synonymous with pupillary response, which may be pupillary constriction or dilation. Right pupillary reflex means reaction of the right pupil, whether light is shone into the left eye, right eye, or both eyes.
Why do pupils constrict with light?
In bright light, your pupils get smaller (constrict) to limit the amount of light that enters. In the dark, your pupils get bigger (dilate). That allows more light in, which improves night vision.
How is the pupil reflex controlled by the nervous system?
Pupillary Reflex Pathways. The pupil is under competing autonomic control in response to light levels hitting the retina. The sympathetic system will dilate the pupil when the retina is not receiving enough light, and the parasympathetic system will constrict the pupil when too much light hits the retina.
What does the pupillary reflex in the human eye do quizlet?
When both pupils contract/dilate in response to a stimulus or lack of stimulus to one eye. Shining the light on one eye sends a signal to the brain telling the brain that there is a bright light and the brain responds by sending a signal to constrict both eyes. What is the receptor in the pupillary reflex?
What is the receptor in the pupillary reflex?
:Pupillary Reflexes test both, the retina of the eye is the receptor, the optic nerve holds the afferent fibers, the oculomotor nerve contains the efferent fibers, and the smooth muscle of the iris is the effector organ.
Is pupillary reflex sympathetic or parasympathetic?
Pupil dilation is mediated by a sympathetic output acting in opposition to parasympathetically mediated pupil constriction. While light stimulates the parasympathetic output, giving rise to the light reflex, it can both inhibit and stimulate the sympathetic output.
How does pupillary reflex help the body?
The pupillary light reflex ( PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil , in response to the intensity ( luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation of vision to various levels of lightness/darkness.
What are the purposes of the pupillary light reflex?
Pupillary light reflex. The pupillary light reflex ( PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil , in response to the intensity ( luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation to various levels of lightness/darkness.
How do pupils respond to light?
Pupil dilation in response to light is a symptom in which a both of a person’s pupils constrict when light is first shined into the good eye, but then both pupils dilate when light switched to the worse eye. This symptom means that the brain is perceiving less light from the worse eye.
What is the protective aspect of the pupillary light reflex?
The pupillary light reflex protects the retina from excessive illumination, which is damaging to the photoreceptors. The corneal reflex protects the eye from trauma. The crossed-extensor reflex withdraws the injured limb from the painful stimulus while simultaneously extending the opposite limb.