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Individual differences |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |
Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)
|Iris dilator muscle|
|Iris, front view. (Muscle visible but not labeled.)|
|The upper half of a sagittal section through the front of the eyeball. ("Radiating fibers" labeled near center.)|
|Latin||musculus dilatator pupillae|
|Gray's||subject #225 1013|
|Nerve:||superior cervical ganglion (sympathetics)|
|Antagonist:||iris sphincter muscle|
The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle of the eye. It is innervated by the sympathetic system, which acts by releasing noradrenaline, which acts on α1-receptors.. Thus, when presented with a threating stimuli that activates the fight-or-flight response, this innervation dilates the iris, thus temporarily letting more light reach the retina.
It has the opposite effect to the iris sphincter muscle
- ↑ jneurosci.org Muscarinic and Nicotinic Synaptic Activation of the Developing..
- ↑ Rang, H. P. (2003). Pharmacology, Edinburgh: Churchill Livingstone. Page 163
- Description of function at tedmontgomery.com
- Slide at mscd.edu
- Dictionary at eMedicine dilator+pupillae+muscle
- Histology at Boston University 08010loa
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