How To Remove An Embedded Tick On A Dog Or A Cat. 1  1. First, you have to locate where the tick is by pushing the fur away from the site. 2  2. Get tweezers or a tick removal tool with thin ends and grip the tick sideways near its head. 3  3. Try to pull it quickly so that the wound will not be infected.
The pupillary light reflex (PLR) is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retinal ganglion cells of the eye, thereby assisting in adaptation to various levels of lightness/darkness.he pupillary reflex pathway begins with the photosensitive retinal ganglion cells, which convey information to the optic nerve (via the optic disc). The optic nerve connects to the pretectal nucleus of the upper midbrain, bypassing the lateral geniculate nucleus and the primary visual cortex.
The physiology behind a normal pupillary constriction is a balance between the sympathetic and parasympathetic nervous systems. Parasympathetic innervation leads to pupillary constriction. A circular muscle called thesphincter pupillae accomplishes this task. The fibers of the sphincter pupillae encompass the pupil. The pathway of pupillary constriction begins at the Edinger-Westphal nucleus near the occulomotor nerve nucleus.