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What part of the brain is involved with the consensual light reflex?
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What is the purpose of consensual light reflex?
Prevents damage to the photoreceptor cells
Is the pupillary light reflex contralateral or ipsilateral?
The patellar reflex is ipsilateral. If the stimulus is applied to left knee cap, the left knee responds. On the other hand, if the right knee were to respond to a left knee stimulus, the response would be considered contralateral.
Is the pupillary light reflex sympathetic?
While pupillary size in principle is controlled both by the sympathetic and the parasympathic nervous system, the typical closure of the pupil after illumination (i.e. the pupillary light reflex) is mediated by the parasympathetic innervation of the constrictor muscle of the pupil.
Why would such a response be of significant value in pupillary reflex?
Clinical significance[edit]In addition to controlling the amount of light that enters the eye, the pupillary light reflex provides a useful diagnostic tool. It allows for testing the integrity of the sensory and motorfunctions of the eye.[1]Under normal conditions, the pupils of both eyes respond identically to a light stimulus, regardless of which eye is being stimulated. Light entering one eye produces a constriction of the pupil of that eye, the direct response, as well as a constriction of the pupil of the unstimulated eye, the consensual response. Comparing these two responses in both eyes is helpful in locating a lesion.[1][5]For example, a direct response in the right pupil without a consensual response in the left pupil suggests a problem with the motor connection to the left pupil (perhaps as a result of damage to the oculomotor nerve or Edinger-Westphal nucleus of the brainstem). Lack of response to light stimulation of the right eye if both eyes respond normally to stimulation of the left eye indicates damage to the sensory input from the right eye (perhaps to the right retina or optic nerve).[1]Emergency room physicians routinely assess the pupillary reflex because it is useful for gauging brain stem function. Normally, pupils react (i.e. constrict) equally. Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates.Normally, both pupils should constrict with light shone into either eye alone. On testing each reflex for each eye, several patterns are possible.[6]Optic nerve damage on one side: (Example in parens.: Left optic nerve lesion) The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, neither pupil constricts, as no signals reach the brain from the left eye due to its damaged optic nerve)The ipsilateral consensual reflex is intact (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)The contralateral direct reflex is intact (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)The contralateral consensual reflex is lost (because light shone into the eye on the damaged side cannot signal to the brain; therefore, despite the right eye's motor pathway (oculomotor nerve) being intact, no signals from the left eye are able to stimulate it due to the damage to the sensory pathway (optic nerve) of the left eye)Oculomotor nerve damage on one side: (Example in parens: Left oculomotor lesion) The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, only the right pupil constricts)The ipsilateral consensual reflex is lost (Example: when the right eye is stimulated, only the right pupil constricts)The contralateral direct reflex is intact (because light shone into both eyes can still signal to the brain, and the pupil on the undamaged side will still be able to constrict via its normal oculomotor nerve)The contralateral consensual reflex is intact (because light shone into the left eye can still signal to the brain via the normal optic nerve, causing attempted constriction of both pupils; the contralateral pupil constricts via its normal oculomotor nerve, but the ipsilateral pupil is unable to constrict due to its damaged oculomotor nerve)
Light shown into the eye will result in a decrease of the papillary diameter which nerves are involved in this reflex?
oculomotor
What is the purpose of consensual light reflex?
Prevents damage to the photoreceptor cells
Is the pupillary light reflex contralateral or ipsilateral?
The patellar reflex is ipsilateral. If the stimulus is applied to left knee cap, the left knee responds. On the other hand, if the right knee were to respond to a left knee stimulus, the response would be considered contralateral.
What is the consensual reflex of the pupil?
the pupil gets smaller because there is an abundance of light present.
Is the pupillary light reflex sympathetic?
While pupillary size in principle is controlled both by the sympathetic and the parasympathic nervous system, the typical closure of the pupil after illumination (i.e. the pupillary light reflex) is mediated by the parasympathetic innervation of the constrictor muscle of the pupil.
Is the response of your pupil a reflex or a voluntary action?
The constriction of pupils in response to bright light is called the pupillary light reflex. If the light is shining directly into one eye, then the pupil in that eye will constrict (a direct response), but so will the pupil in the non-illuminated eye (a consensual response).This reflex involves two cranial nerves: the optic nerve, which senses the light, and the oculomotor nerve, which constricts both pupils. It is considered involuntary since you don't think about it.
Why would such a response be of significant value in pupillary reflex?
Clinical significance[edit]In addition to controlling the amount of light that enters the eye, the pupillary light reflex provides a useful diagnostic tool. It allows for testing the integrity of the sensory and motorfunctions of the eye.[1]Under normal conditions, the pupils of both eyes respond identically to a light stimulus, regardless of which eye is being stimulated. Light entering one eye produces a constriction of the pupil of that eye, the direct response, as well as a constriction of the pupil of the unstimulated eye, the consensual response. Comparing these two responses in both eyes is helpful in locating a lesion.[1][5]For example, a direct response in the right pupil without a consensual response in the left pupil suggests a problem with the motor connection to the left pupil (perhaps as a result of damage to the oculomotor nerve or Edinger-Westphal nucleus of the brainstem). Lack of response to light stimulation of the right eye if both eyes respond normally to stimulation of the left eye indicates damage to the sensory input from the right eye (perhaps to the right retina or optic nerve).[1]Emergency room physicians routinely assess the pupillary reflex because it is useful for gauging brain stem function. Normally, pupils react (i.e. constrict) equally. Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates.Normally, both pupils should constrict with light shone into either eye alone. On testing each reflex for each eye, several patterns are possible.[6]Optic nerve damage on one side: (Example in parens.: Left optic nerve lesion) The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, neither pupil constricts, as no signals reach the brain from the left eye due to its damaged optic nerve)The ipsilateral consensual reflex is intact (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)The contralateral direct reflex is intact (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)The contralateral consensual reflex is lost (because light shone into the eye on the damaged side cannot signal to the brain; therefore, despite the right eye's motor pathway (oculomotor nerve) being intact, no signals from the left eye are able to stimulate it due to the damage to the sensory pathway (optic nerve) of the left eye)Oculomotor nerve damage on one side: (Example in parens: Left oculomotor lesion) The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, only the right pupil constricts)The ipsilateral consensual reflex is lost (Example: when the right eye is stimulated, only the right pupil constricts)The contralateral direct reflex is intact (because light shone into both eyes can still signal to the brain, and the pupil on the undamaged side will still be able to constrict via its normal oculomotor nerve)The contralateral consensual reflex is intact (because light shone into the left eye can still signal to the brain via the normal optic nerve, causing attempted constriction of both pupils; the contralateral pupil constricts via its normal oculomotor nerve, but the ipsilateral pupil is unable to constrict due to its damaged oculomotor nerve)
What is cranial reflex?
A cranial reflex is a fast, involuntary response to a stimulus. It uses the brain stem as an integrating center (the brain receives sensory information and generates a response). This is contrasted to a spinal reflex, when the response is generated in the spinal cord itself, and the brain only finds out a reflex has occurred after the fact.An example of a cranial reflex would be the tracking movements of your eyes as you are reading this sentence. The dilation and contraction of your pupils in response to different levels of light is another cranial reflex.--------------An example of a spinal reflex would be standing on a pin or touching a hot object.
Light shown into the eye will result in a decrease of the papillary diameter which nerves are involved in this reflex?
oculomotor
Is the pupillary light reflex autonomic and somatic?
Pupillary light reflex is autonomic.
What part of brain controls pupil dilation?
Edinger-Westphal nucleus of the brainstem controls the pupil reflex. An ER doctor who looks at the response to a pen light is checking on brain stem activity.
Is pupillary light reflex a monosynaptic or polysynaptic reflex?
It is Polysynaptic
What is the consensual response when a light is shone in eye?
Your eye dilates
