LIGHT REFLEX Meaning and
Definition
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The light reflex, also known as the pupillary light reflex or direct pupillary response, is a phenomenon in which the muscles of the iris (the thin, circular structure of the eye surrounding the pupil) contract or dilate in response to changes in light intensity. More specifically, it refers to the constriction of the pupil when exposed to bright light and its subsequent dilation when the lighting conditions become dimmer.
This reflex is controlled by the autonomic nervous system, specifically the parasympathetic nervous system, which regulates involuntary bodily functions. When the eyes are exposed to bright light, the parasympathetic nervous system is stimulated, causing the pupillary sphincter muscle to constrict, resulting in a reduced pupil size. On the other hand, in darkness or low light settings, the sympathetic nervous system takes control and signals the pupillary dilator muscle to enlarge the pupil, allowing more light to enter the eye for improved visibility.
The light reflex is an essential mechanism that helps in maintaining optimal visual perception by regulating the amount of light entering the eye. It is unintentional and typically occurs without conscious effort, ensuring that the eyes are adequately protected from excessive or insufficient light levels. The light reflex is a fundamental part of the overall process of the human visual system and ensures an appropriate balance between light intake and retinal exposure.
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A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
Common Misspellings for LIGHT REFLEX
- kight reflex
- pight reflex
- oight reflex
- lught reflex
- ljght reflex
- lkght reflex
- loght reflex
- l9ght reflex
- l8ght reflex
- lifht reflex
- livht reflex
- libht reflex
- lihht reflex
- liyht reflex
- litht reflex
- liggt reflex
- ligbt reflex
- lignt reflex
- ligjt reflex
Etymology of LIGHT REFLEX
The term "light reflex" is derived from the combination of two words: "light" and "reflex".
The word "light" originates from the Old English word "leoht" which means "brightness" or "radiance". It ultimately has Proto-Germanic and Proto-Indo-European roots.
The term "reflex" comes from the Latin word "reflexus", which means "bent back" or "turned back". It is built from the combination of the prefix "re-" (indicating backward or again) and the Latin word "flectere" (meaning "to bend" or "to turn").
Together, "light reflex" refers to the automatic response of the eye to alterations in light intensity by adjusting the size of the pupil.
Similar spelling words for LIGHT REFLEX
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