what happens in the body when you come home from school, smell cookies baking, run to the kitchen to see if they're done and take one? You eat the whole cookie and drink a glass of milk. How many body systems are involved? What role does each play?

5 body system

Explanation:

The aroma from the cookies get in into the nostril with oxygen through respiration system.This diffuses through the nostril to the olfactory lobe.

Endocrine system stimulates the production saliva from the salivary glands into the mouth.This is salivation.

Running to the kitchen  and picking one involved the activity of skeletal and muscular systems systems through contraction of muscles and supports by the bones

The olfactory lobe is in the olfactory system  of the nervous system,This is transfer to the brain -to the olfactory cortex for analysis.

When the food is eaten,the taste sensation is sent to the orbital cortex for the blend of taste and aroma of the cookies to give a pleasant flavour.

Likewise the digestion of cookies begin in the mouth,while that of the milk starts in the stomach.This is digestive system