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Pupillary constriction is primarily controlled by the parasympathetic nervous system, specifically through the action of the oculomotor nerve (cranial nerve III). When light enters the eye, the oculomotor nerve stimulates the iris sphincter muscle, causing the pupil to constrict and reduce the amount of light entering the eye. This reflex is known as the pupillary light reflex.
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What cranial nerve causes pupil consriction?
A dilated pupil is when the black part of the eye becomes big due to reactions to light or medication. A fixed pupil is one where the black part is stuck open big due to pressure inside of the eye.
What nerve acts as the afferent pathway in the pupillary reflex?
The optic nerve (cranial nerve II) carries sensory information about light intensity to the brain as part of the afferent pathway in the pupillary reflex.
Light shown into the eye will result in a decrease of the papillary diameter which nerves are involved in this reflex?
The autonomic nervous system is responsible for controlling the pupillary reflex. The parasympathetic nerves, specifically the oculomotor nerve (cranial nerve III), cause constriction of the pupils in response to light.
What part of the PNS controls the pupillary response?
Pupillary response is controlled by the autonomic nervous system.In bright light or when looking at close objects, the parasympathetic nervous system will cause pupillary constriction by activating the sphincter pupillae muscle(s). The parasympathetic nerves that innervate the sphincter pupillae are the short ciliary nerves, which come from the ciliary ganglion in the orbit. Innervation of the ciliary ganglion is via parasympathetic pre-ganglionic fibers traveling with the occulomoter nerve from the edinger-westfall nucleus in the cranial midbrain.In low light, when looking at distant objects, or when stress levels are high (fight or flight) the sympathetic nervous system will cause pupillary dilation by activating the iris dilator muscle(s). The sympathetic nerves that innervate these muscles come from the superior cervical ganglion.
What part in pupil reflex of coordinator?
The pupil reflex, specifically the pupillary light reflex, involves coordination between the optic nerve (cranial nerve II) and the oculomotor nerve (cranial nerve III). When light is shone in one eye, the optic nerve transmits signals to the brain, which then sends motor signals through the oculomotor nerve to constrict the pupil of both the illuminated eye and the other eye (consensual reflex). This reflex helps regulate the amount of light entering the eye and protects the retina from excessive illumination.
What cranial nerve causes pupil consriction?
A dilated pupil is when the black part of the eye becomes big due to reactions to light or medication. A fixed pupil is one where the black part is stuck open big due to pressure inside of the eye.
What nerve acts as the afferent pathway in the pupillary reflex?
The optic nerve (cranial nerve II) carries sensory information about light intensity to the brain as part of the afferent pathway in the pupillary reflex.
What is persistent pupillary membrane of the eye?
Persistent pupillary membrane is a condition where parts of a fetal membrane stay attatched to the eye after birth. It can cause cataracts.
Light shown into the eye will result in a decrease of the papillary diameter which nerves are involved in this reflex?
The autonomic nervous system is responsible for controlling the pupillary reflex. The parasympathetic nerves, specifically the oculomotor nerve (cranial nerve III), cause constriction of the pupils in response to light.
What is the receptor in pupillary reflex and the effector do both change simultaneously in pupillary reflex?
The receptor in the pupillary reflex is the optic nerve, which senses changes in light intensity. The effector is the circular and radial muscles of the iris, which control the size of the pupil. In the pupillary reflex, both the receptor and the effector work together to adjust the size of the pupil to regulate the amount of light entering the eye.
What two cranial nerves on the stimulated side must be functional for pupillary light reflex to occur?
The two cranial nerves that must be functional for the pupillary light reflex to occur are cranial nerve II (optic nerve) for the afferent pathway (carrying the visual information from the retina to the brain) and cranial nerve III (oculomotor nerve) for the efferent pathway (carrying the motor response to constrict the pupil).
What part of the PNS controls the pupillary response?
Pupillary response is controlled by the autonomic nervous system.In bright light or when looking at close objects, the parasympathetic nervous system will cause pupillary constriction by activating the sphincter pupillae muscle(s). The parasympathetic nerves that innervate the sphincter pupillae are the short ciliary nerves, which come from the ciliary ganglion in the orbit. Innervation of the ciliary ganglion is via parasympathetic pre-ganglionic fibers traveling with the occulomoter nerve from the edinger-westfall nucleus in the cranial midbrain.In low light, when looking at distant objects, or when stress levels are high (fight or flight) the sympathetic nervous system will cause pupillary dilation by activating the iris dilator muscle(s). The sympathetic nerves that innervate these muscles come from the superior cervical ganglion.
A sudden flash of bright light would cause?
Contraction of the pupillary contrictor muscles.
Is the optic nerve a sensory or motor nerve?
The optic nerve is a cranial nerve (CN II) that sends special somatic afferent (sensory) fibers to the lateral geniculate of the thalamus. Here, they synapse and continue via optic radiations to the primary visual cortex of the brain. The motor portion of the eye is controlled by cranial nerves as well only they are: Oculomotor (CN III), Trochlear (CN IV), and Abducens (CN VI); there is also some sympathetic innervation (not from cranial nerves) that cause pupillary dialation.
What is meant by the term ''reflex''?
A reflex is an automatic or involuntary response to a stimulus, typically involving a sensory nerve and a motor nerve. It is a rapid and predictable reaction that helps protect the body from harm. Examples include the knee-jerk reflex and the pupillary reflex.
Lap Band fill cause Vagus nerve damage?
The vagus nerve is located in the arm of a human. The lap band fill procedure can cause nerve damage to this nerve.
Is pupillary light reflex a monosynaptic or polysynaptic reflex?
The pupillary light reflex is a polysynaptic reflex. When light is sensed by the retina, a signal is sent via the optic nerve to the pretectal nuclei in the midbrain, which then sends signals to both the parasympathetic and sympathetic pathways controlling the muscles of the iris to constrict or dilate the pupil appropriately.
