Automation in the Body

Our bodies are smart, like really smart. Think about all of the things your body does without any effort or thought. When was the last time you thought about breathing? I know when I actively think about it, I get off rhythm, can’t remember how to actually do it, and have to go into yoga breathing just to reset. Thankfully, we do not have conscious control over these extremely important functions in our bodies. Could you imagine having to sentiently control your breathing while sleeping? Or better yet, how difficult would it be to keep your heart rate low while listening to a great song on the radio? I for one, am happy to have an Autonomic Nervous System (ANS) that will do the important, life required functions for me.

The ANS largely and unconsciously influences the internal organs and regulates bodily functions. The ANS is responsible for pupillary responses, cardiac regulator, digestion, respiratory rate, and many more, all of which are regulated by a part of the brain called the Hypothalamus.

There are three branches of the ANS: the Sympathetic Nervous System (SNS), the Parasympathetic Nervous System(PSNS), and the Enteric Nervous System (ENS).

The SNS is regulated by the Pre-Vertebral Ganglion and is often described as “fight or flight.” When your body’s SNS is in control, it is on high alert. Your body diverts blood from the stomach and intestines to the muscles and the heart, preparing you for whatever life throws your way. This raises your heart rate and blood pressure, your pupils dilate and respiratory pathways open to allow more air to enter your lungs. The important neurotransmitters are nor-adrenaline (nor-epinephrine) and adrenaline (epinephrine).

The PSNS is regulated by the Vagus Nerve and is commonly known as “rest and digest” or “feed and breed”. Bodily functions that occur or increase during this time are sexual arousal, salivation (saliva), lacrimation (tears), urination, defecation, and more. When your body is under the influence of the PSNS, your heart rate slows down, your digestion and glandular functions increase and the primary neurotransmitter is acetylcholine.

The last branch is the ENS. It’s also known as the second brain. The ENS uses over 30 different neurotransmitters this includes 90% of the body’s serotonin and 50% of the body’s dopamine. Serotonin is responsible for sleep, digestion, memory, sexual desire, mood regulation, appetite and more. While dopamine plays a role in how we feel pleasure, it also helps us to strive, focus, and find things interesting. The ENS governs the gastrointestinal tract and can act independently of the PSNS and SNS. The ENS can also work independently of the brain and spinal cord. It does rely on the vagus nerve, but if the vagus nerve is severed, it can still function. Also, the ENS controls the motor functions of the gastrointestinal tract as well as the secretion of the enzymes needed for digestion.