Autonomic Nervous System

Do you feel extremely satisfied with food on certain days while lack of satisfaction on other days in spite of having same quantity and quality of food? Do you overeat when you are stressed? Today’s article is going to explain you how our digestive system works. Also it will explain the relation between our mood and our eating process. Our body works in two ways with regards to digestive system. Either it is in digestive mode or in non digestive mode. The Autonomic Nervous System (ANS) is the part of Central Nervous System (CNS) is responsible to control organs, heart, lungs, stomach, blood vessels and brain. It communicates with body with the help of nerves. The sensory impulses from the blood vessels are passed to the brain and vice versa because of the ANS. Today we are talking about one of the ANS function – Digestive Process and how it passes the nutrients from the food to the various parts of the body.

ANS divides every situation in two ways and accordingly works on it.

1. Emergency situations which causes stress and require us to either fight or run away.
2. Non emergency situations where our mind is relaxed.

Consider the situation when you are enjoying the wild life or enjoying the adventures. Suddenly you saw the tiger or the snake coming towards you. Though it is lifetime achievement to experience such things but they are scary too isn’t it? At that point of time it is better that our nervous system works on guiding us on how to run from that situation instead of putting energies into digesting the food that you had at lunch.

Two parts of ANS in scientific terms are - Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS). SNS is responsible to put off the digestive mode and put the thinking process on to face the emergency situation. PNS is responsible to actively work on the digestive mode. When SNS is active, PNS is inactive and vice versa. This means when PNS is on digestive system works actively and when SNS is on digesting system does not work. This is the reason we are satisfied when we eat food in the relaxed manner and less satisfied when we are eating anxiously or in stressed manner.

Main functions of SNS includes accelerates heart rate, conversion of glycogen to glucose, increasing blood flow to vital organs like heart and brain, limits blood flow to stomach to thereby preventing digestion, etc. PNS main functions include reducing blood pressure; stimulate saliva which is the first step towards digestion, increase blood flow to stomach and liver that aids in digestion process. Are you thinking why both do not function at the same time? Let me clarify.

Why our body requires switching between these two processes?

1. When there is no food in our stomach there is no need for our body to work on digestive process.
2. Situations where we require our thinking process to work faster for instance in conference meetings. More energy and blood flow is diverted to brain to think faster instead of working on the digestive mode.
3. Our digestive system needs to work more actively when we eat food and less at other times.
4. Eating in the stressed or challenging situations surpasses the digestive mode so as our mind can think faster and find the solution of the situation that is faced.

Hence it makes sense that when there is no requirement or during emergency situations our body should not waste energy on digestion process. Also digestion works to its maximum extent when eating takes place in relaxed manner.