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1. Simple behavior in which a stimulus evokes a response without involving the brain, e.g. a knee jerk.
2. The body’s automatic, involuntary response to a stimulus.
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|Noun||1.||reflex action - an automatic instinctive unlearned reaction to a stimulus|
inborn reflex, innate reflex, instinctive reflex, physiological reaction, reflex, reflex response, unconditioned reflex
accommodation reflex - reflex changes in the eyes that enable an object to be focused on the retina
Babinski, Babinski reflex, Babinski sign - extension upward of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front; normal in infants under the age of two years but a sign of brain or spinal cord injury in older persons
belch, burp, burping, eructation, belching - a reflex that expels gas noisily from the stomach through the mouth
blink, blinking, eye blink, nictation, nictitation, winking, wink - a reflex that closes and opens the eyes rapidly
disgorgement, emesis, puking, vomiting, regurgitation, vomit - the reflex act of ejecting the contents of the stomach through the mouth
yawn, yawning, oscitance, oscitancy - an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom; "he could not suppress a yawn"; "the yawning in the audience told him it was time to stop"; "he apologized for his oscitancy"
electrical shock, shock, electric shock - a reflex response to the passage of electric current through the body; "subjects received a small electric shock when they made the wrong response"; "electricians get accustomed to occasional shocks"
response, reaction - a bodily process occurring due to the effect of some antecedent stimulus or agent; "a bad reaction to the medicine"; "his responses have slowed with age"
knee jerk, knee-jerk reflex, patellar reflex - a reflex extension of the leg resulting from a sharp tap on the patellar tendon
light reflex, pupillary reflex, miosis, myosis - reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller
mydriasis - reflex pupillary dilation as a muscle pulls the iris outward; occurs in response to a decrease in light or certain drugs
micturition reflex - relaxation of the urethral sphincter in response to increased pressure in the bladder
gag reflex, pharyngeal reflex - normal reflex consisting of retching; may be produced by touching the soft palate in the back of the mouth
goose bump, goose pimple, goose skin, goosebump, gooseflesh, horripilation, pilomotor reflex - reflex erection of hairs of the skin in response to cold or emotional stress or skin irritation
plantar reflex - flexion of the toes when the sole of the foot is stroked firmly on the outer side from the heel to the front in persons over the age of 2 years; under 2 years the results should be extension of the toes (Babinski reflex)
rooting reflex - reflex consisting of head-turning and sucking movements elicited in a normal infant by gently stroking the side of the mouth or cheek
myotactic reflex, stretch reflex - reflex contraction of a muscle when an attached tendon is pulled; important in maintaining erect posture
suckling reflex - reflex behavior in newborn mammals; includes finding and grasping the nipple in the mouth and sucking on it and swallowing the milk
sneeze, sneezing, sternutation - a symptom consisting of the involuntary expulsion of air from the nose