(poor'kin-ye, -yā )

Jan Evangelista Purkinje, Bohemian anatomist and physiologist, 1787–1869.

P. cell A large cerebellar cortex neuron with an ornate, antler-shaped dendritic arbor. Purkinje cells receive inputs (climbing fibers) from the inferior olive, and they send their axons (inhibitory) to the cerebellar and vestibular nuclei. SYN: Purkinje neuron.

P. fiber A cardiac muscle cell beneath the endocardium of the ventricles of the heart. These extend from the bundle branches to the ventricular myocardium and form the last part of the cardiac conduction system.

P. figures Shadows of blood vessels perceived when light is projected out of focus or obliquely onto the retina.

P. layer A single row of large flask-shaped cells (Purkinje cells) lying between molecular and granular layers of the cerebellar cortex.

P. network A network of Purkinje fibers found in cardiac muscle.

P. neuron Purkinje cell.

P. phenomenon The adjustment of the pupil of the eye to light intensity. When the eye adapts from light to dark conditions, the maximum pupillary movement is caused by green instead of yellow light. SYN: pupillomotor reflex.

P.-Sanson images Three images of the same object, produced by reflections from the surface of the cornea and the anterior and posterior surfaces of the lens of the eye. For the most part, the viewer adapts to this phenomenon and ignores these extra images.

P. vesicle The nuclear portion of an ovum. SYN: germinal vesicle.