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.
In bright light, the iris closes (or constricts) and makes the pupil opening smaller to restrict the amount of light that enters your eye. The iris in bright light. In dim light, the iris opens (or dilates) and makes the pupil opening larger to increase the amount of light that enters your eye:The iris in dim light. In addition, it is the iris that determines your eye color.he iris is a tissue inside the eye that has a hole in the center called the pupil. The iris contains muscles that allow the pupil to become larger (open up or dilate) and smaller (close up or constrict).