There's a direct neural link from the nasal cavity right into the brain stem. Neurons that pick up smell, and trigger your reptile brain. Smell is our oldest sense, and the most intimate one. BTW COVID attacked those neurons in a subset of people. That's what led to loss of smell/taste, as those very neural cells were converted to virus 🦠 particles. The five basic tastes (sour/bitter/salty/sweet/umami) are taken up in the mouth, but aroma is all in the nose.

Source: lecture on smell at Mainz university, 2022-ish.