Chemoreceptor and Olfactory organ

Chemoreceptor noun - A sensory receptor that responds to chemical stimuli.

Olfactory organ and chemoreceptor are semantically related. In some cases you can replace phrase "Olfactory organ" with "Chemoreceptor", this terms are similar.

Olfactory organ noun - The organ of smell and entrance to the respiratory tract; the prominent part of the face of man or other mammals.

Chemoreceptor and olfactory organ are semantically related. You can use "Chemoreceptor" instead a noun phrase "Olfactory organ".