physiological reaction vs instinctive reflex

physiological reaction and instinctive reflex both are nouns.

Word	Noun	Adjective	Verb	Adverb
physiological reaction	Yes	No	No	No
instinctive reflex	Yes	No	No	No

As nouns, physiological reaction and instinctive reflex are synonyms defined as:

physiological reaction and instinctive reflex: an automatic instinctive unlearned reaction to a stimulus

Other synonyms of physiological reaction include inborn reflex, innate reflex, reflex, reflex action, reflex response, unconditioned reflex.

physiological reaction (noun)	instinctive reflex (noun)
an automatic instinctive unlearned reaction to a stimulus	an automatic instinctive unlearned reaction to a stimulus