The autonomic nervous system is made up of two main parts:

1. Sympathetic System:

   • This part helps our body react in stressful situations.
   • It's often called the "fight or flight" response.
   • When we're stressed, it can make our heart beat about 30% faster.
   • It also opens up our pupils and lungs but slows down digestion.
   • The chemical that helps send messages in this system is called norepinephrine.

2. Parasympathetic System:

   • This part helps our body relax and digest food.
   • It's known as the "rest and digest" response.
   • It slows down the heart rate, bringing it back to a normal pace of about 60-100 beats per minute.
   • It also helps with digestion and saves energy.
   • The chemical used here to send messages is called acetylcholine.

Both of these systems work together to keep our body balanced and healthy.