The ocular system comprises the eyes and associated structures responsible for capturing light and converting it into nerve signals, which are interpreted by the brain as visual images. The human eye contains components such as the cornea, iris, pupil, lens, and retina, which work together to focus light and transmit it to the retina. The retina contains photosensitive cells (cones and rods) that detect light and color and send this information to the brain through the optic nerve. The ocular system also includes muscles that move the eyeball, allowing the adjustment of gaze direction.

The brain, in turn, is the control center of the central nervous system, responsible for processing all sensory information, including that from the eyes, as well as regulating motor, cognitive, and emotional functions. The visual cortex, located at the back of the brain, interprets nerve impulses sent by the eyes, transforming them into recognizable images. Besides visual functions, the brain coordinates all facial and body muscles, enabling facial expressions and complex movements.

The muscles of the head are crucial for functions such as chewing, speaking, and facial expressions. These include facial muscles that control skin movements and are responsible for emotional expressions like smiling and frowning. Specific muscles, such as the masseter and temporal, are responsible for chewing. Other muscles, like the orbicularis oculi and orbicularis oris, control eye and lip movements, respectively, playing important roles in both communication and the protection of the eyes and mouth.