AN ANALYSIS OF THE FORCES DETERMINING THE SIZE OF THE PUPIL
| Autor: | Martin Davanger |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
genetic structures
Iris Pupil Optics medicine Humans Iris (anatomy) Dilatator pupillae Intraocular Pressure Mathematics Rest (physics) business.industry Tension (physics) Sphincter pupillae Astrophysics::Instrumentation and Methods for Astrophysics General Medicine Mechanics Constriction Dilatation eye diseases Ophthalmology medicine.anatomical_structure Oculomotor Muscles Caliber Sphincter sense organs business Muscle Contraction |
| Zdroj: | Acta Ophthalmologica. 50:183-187 |
| ISSN: | 1755-375X |
| DOI: | 10.1111/j.1755-3768.1972.tb03776.x |
| Popis: | The constricting effect of sphincter, and the dilating effect of dilatator, vary inversely proportionally to the size of the pupil. The forces of dilatator and sphincter, which determine the size of the pupil, may be considered as analogous to the forces determining the caliber of a cylindrical elastic vessel, namely the pressure in the vessel and the tension of its wall. The equation S=d · r is analogous to the law of Laplace T=P · r. The pupil is at rest when the force of dilatator is 2π times the force of sphincter. This relationship is the condition of equilibrium. If from a state of equilibrium the force of one or both muscles is changed, the pupil contracts or dilates until the condition of equilibrium, as stated above, is again established. |
| Databáze: | OpenAIRE |
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