Autonomic Nervous System
Human Physiology & Health > Nervous System
Parasympathetic and Sympathetic nervous system Parasympathetic and Sympathetic nervous system The division of sympathetic nervous system often referred as "fright–or–flight" systems because they prepare the body for emergencies. The division of parasympathetic nervous system helps to conserve and restores the energies. They direct the blood to flow through the digestive tract for active digestion of food.

The autonomic nervous system (ANS) regulates the functions of our internal organs (the viscera) such as the heart, stomach and intestines. The ANS is part of the peripheral nervous system and it also controls some of the muscles within the body. We are often unaware of the ANS because it functions involuntary and reflexively. For example, we do not notice when blood vessels change size or when our heart beats faster. The ANS can be divided into three parts: Sympathetic, Para–sympathetic and Enteric nerves.

The division of sympathetic nervous system often referred as "fright–or–flight" systems because they prepare the body for emergencies. They help in increasing the blood pressure by precluding the blood to the muscles. They also increase the heart and breathing rates in order to make the person to cope with stressful situations. The nerves of sympathetic division often have an opposite effect when they are placed within the same organs as parasympathetic nerves.

The division of parasympathetic nervous system helps to conserve and restores the energies. They direct the blood to flow through the digestive tract for active digestion of food. Their activation usually cause opposite responses that promote appeasing and a return to self–maintenance functions. It also helps to maintain the blood pressure, heart rate and breathing rate at a very low level. So, it is called as "rest and digest" system. The huge network of neurons across the digestive tract, pancreas and the gallbladder together form the enteric division. These neurons have a control over these organs as well as on secretions in the smooth muscles that produce peristalsis. Sometimes it though it is considered as an independent division usually it is regulated by the both sympathetic and parasympathetic divisions.

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