PUPILLARY REFLEX Meaning and
Definition
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Pupillary reflex refers to an automatic and involuntary response of the pupil of the eye to changes in lighting conditions or other stimuli. The pupil is the black circular opening located in the center of the iris, which controls the amount of light that enters the eye. The size of the pupil is regulated by the muscles of the iris, known as the pupillary sphincter and dilator muscles.
The pupillary reflex involves a complex neurological process that is controlled by the autonomic nervous system. When light levels change, receptors in the retina of the eye called photoreceptors send signals to the brain, specifically to the Edinger-Westphal nucleus, which is part of the oculomotor nerve.
In response to an increase in light intensity, a constriction or narrowing of the pupil occurs, reducing the amount of light entering the eye. This is known as the pupillary light reflex. Conversely, in low light conditions, the pupil dilates or expands to allow more light into the eye, enhancing visual acuity. This is called the pupillary dark reflex.
The pupillary reflex is important for maintaining optimal visual perception by regulating the amount of light that reaches the retina. It helps protect the eye from excessive light exposure that can be harmful and ensures adequate light reception in dimly lit environments. In addition to light, other stimuli such as pain, emotions, and certain medications can also trigger pupillary reflexes.
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Contraction of the pupil under the stimulus of light.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
Common Misspellings for PUPILLARY REFLEX
- oupillary reflex
- lupillary reflex
- -upillary reflex
- 0upillary reflex
- pypillary reflex
- phpillary reflex
- pjpillary reflex
- pipillary reflex
- p8pillary reflex
- p7pillary reflex
- puoillary reflex
- pulillary reflex
- pu-illary reflex
- pu0illary reflex
- pupullary reflex
- pupjllary reflex
- pupkllary reflex
- pupollary reflex
- pup9llary reflex
Etymology of PUPILLARY REFLEX
The word "pupillary" comes from the Latin word "pupilla", which means "little doll" or "puppet". This term is a diminutive form of "pupa", which means "girl" or "doll". The pupil of the eye was compared to a small doll or puppet due to its size and appearance.
The word "reflex" also has Latin origins, derived from the Latin word "reflectere", which means "to bend back". In the context of the pupillary reflex, it refers to the involuntary and automatic contraction or dilation of the pupil in response to light or other stimuli.
Therefore, the term "pupillary reflex" refers to the automatic contraction or dilation of the pupil in response to external stimuli such as light, which is often compared to the behavior of a small doll or puppet.
Similar spelling words for PUPILLARY REFLEX
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