Final answer:
The nervous message triggered by an eyelash being flexed may not go all the way to the brain due to reflex actions. Similar to the corneal reflex, sensory information from the face can travel through the trigeminal nerve, and motor responses like blinking involve the facial nerve. The nervous system, including peripheral nerves, connects the body and the CNS for processing sensations and reflexes.
Step-by-step explanation:
When an eyelash is flexed, it does trigger a nervous message, but this message may not necessarily be sent all the way to the brain. The sensation of the eyelash being flexed activates a reflex action that is part of the body's natural protective mechanisms, similar to the corneal reflex, which is an instantaneous blink response when the cornea is touched. In many reflexes, the sensory information is sent through the peripheral nerves to the spinal cord, where an immediate motor response is generated without the need for the brain's involvement. This process is known as a reflex arc. However, other sensory information from the face, including that from the eyelids, typically travels through the trigeminal nerve and may reach the brain for processing. This can trigger responses like blinking, which involves the facial nerve innervating the muscle responsible for closing the eye, the orbicularis oculi.
Moreover, the nervous system, including the peripheral nerves, facilitates communication between various body parts and the central nervous system, allowing for complex reflex actions and sensations to be processed. These sensory messages can be related to tactile stimuli, as when an eyelash is flexed, or visual stimuli, as when light hits the retina and triggers various reflexes, such as pupillary constriction or dilation, to regulate the amount of light entering the eye.