the pupil gets smaller because there is an abundance of light present.
In the experiment on the photopupillary reflex, when light is shone into one eye causing pupillary constriction (direct response), the nonilluminated eye will also exhibit pupillary constriction (consensual response) due to neural connections between both eyes and the brain. This demonstrates the consensual response component of the pupillary light reflex.
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.
Constriction. When light shines into one pupil, the pupillary light reflex causes the other pupil to constrict due to the connection between the two pupils through the optic nerve and brainstem. This reflex helps regulate the amount of light entering the eye to maintain optimal vision.
Yes, the pupillary light reflex is mediated by both autonomic and somatic nervous systems. The autonomic nervous system controls the constriction of the pupil in response to light, while the somatic nervous system controls the movement of the muscles that dilate and constrict the pupil.
The term is "pupillary light reflex." This reflex causes the pupil to constrict in response to a bright light stimulus, which helps protect the retina from excessive light exposure.
In the experiment on the photopupillary reflex, when light is shone into one eye causing pupillary constriction (direct response), the nonilluminated eye will also exhibit pupillary constriction (consensual response) due to neural connections between both eyes and the brain. This demonstrates the consensual response component of the pupillary light reflex.
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.
The stimulus in the pupil reflex would be light
The pupil dilates when stimulated by the pinching on the nape of the neck.
yes
The oculomotor nerve (cranial nerve III) is responsible for the reflex constriction of the pupil in response to light and accommodation.
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.
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.
Reflexes such as blinking and pupil reflex are centered in the brainstem. The trigeminal nerve is responsible for the blinking reflex, while the pupillary reflex is controlled by the oculomotor nerve. These reflexes help protect the eyes from harm and regulate the amount of light entering the eye.
The pupil reflex is controlled by the autonomic nervous system, specifically the parasympathetic and sympathetic divisions. Constriction of the pupil (miosis) is controlled by the parasympathetic system through the action of the cranial nerve III (oculomotor nerve). Dilation of the pupil (mydriasis) is controlled by the sympathetic system through the action of the superior cervical ganglion.
Pupils reacts to light, narrowing in bright light and widening in poor light - so is a reflex action.
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)