When the doctor shines his light into your eyes or uses his reflex hammer, this action, unpleasant in itself, has the goal of checking your reflexes and thus the state of your nervous functions, because the multitude of bodily reactions, most of which are unconscious to us, shows exactly how our brain performance is doing.
What is a reflex?
A reflex is an automatic, involuntary response of a body organ to a stimulus. This response is immediate to the stimulus and is reproducible, unlike a response that we consciously control.
For a reflex to occur, the body must be able to perceive stimuli, transmit and process them with its neural pathways, and then respond to them in a way that ensures its survival. Whether we suddenly hear a loud noise, something flies into our eye, or we step our foot into a piece of broken glass, the body responds with a schematic response to protect the overall organism:
- At the loud noise with a body rotation in the direction of the noise source, but overall with the escape movement away from the noise source,
- At the irritation of the cornea with the closing of the eyes and turning away the head,
- At the sudden pain in the sole of the foot with the raising of the affected leg and an evasive movement of the body away from danger.
Are there different reflexes?
Medical and behavioral biologists distinguish reflexes according to whether they are innate or acquired, that is, learnable, how many nerves are involved in transmitting the stimulus, and whether the body’s response originates from the site of the stimulus or another organ responds. There are also pathological reflexes, which occur only in certain diseases of the nervous system, and primitive early childhood reflexes, which are lost during the first two years of life and indicate the infant’s stage of development.
To distinguish the many reflexes, they are often named after their discoverer or, like the various muscle intrinsic reflexes, after their place of triggering – the best known is the patellar tendon reflex, which you can trigger in yourself by tapping the tendon just below the kneecap with some momentum while your leg is bent and hanging down: your leg responds by contracting the thigh muscle, which swings the lower leg forward.
What are early childhood reflexes?
Early childhood reflexes are also called primitive reflexes and are used for self-protection, foraging, and feeding. Many of these reflexes are lost during the first two years of life and indicate the infant’s stage of development.
Important early infant reflexes include the search reflex (when a corner of the mouth is touched, the infant turns its head in that direction), the Moro clasp reflex (when the head suddenly falls back, the infant opens and closes its arms), the hand and foot grasp reflex (pressure on the palm of the hand triggers a grasping movement; pressure on the sole of the foot triggers flexion of the toes), and the cry reflex (contact with a pad leads to walking movements).
Some primitive reflexes, such as the swallowing reflex, are retained throughout life – the swallowing reflex ensures that food we ingest enters the esophagus rather than the trachea. In addition, there are many other early childhood reflexes that are checked by the pediatrician during U-1 to U-9 examinations, disappear after a certain interval during normal development, and if they persist, the neurological cause must always be investigated.