Refleksid

Refleksid are the plural form of the Estonian word refleks, referring to reflexes in biology. A reflex is an involuntary, nearly instantaneous motor response to a specific stimulus. Reflexes are typically rapid, stereotyped, and hard-wired, allowing quick protection of the body and maintenance of posture. They arise via a reflex arc, which includes a receptor, a sensory neuron, an integration center (often in the spinal cord or brainstem), a motor neuron, and an effector such as a muscle or gland. Some reflexes are monosynaptic, involving a single synapse between sensory and motor neurons; others are polysynaptic, with one or more interneurons.

Refleksid can be broadly categorized as somatic reflexes, which involve skeletal muscle, and autonomic or visceral reflexes, which regulate glands and smooth muscle. Common somatic reflexes include the stretch (myotatic) reflex, the tendon reflex, and withdrawal reflexes. Autonomic reflexes include pupil constriction in response to light and salivation. Many reflexes are innate and present at birth, while others are learned as conditioned reflexes, demonstrated in Pavlovian conditioning.

Clinical neurology uses reflex assessment to gauge nerve function, with measurements of symmetry, speed, and strength. Abnormal reflexes may indicate nerve or spinal cord injury, disease, or disruption of the brain's higher control. Typical patterns include hyperreflexia (exaggerated responses) and hyporeflexia (diminished responses), or the absence of a reflex. In development, newborns exhibit primitive reflexes that gradually disappear as the nervous system matures.