Autonomic Nervous System

The nervous system is a very complicated structure in the human body. There are millions of neurons are present in a body of a human. The nervous system is the most important component of our body. Human being walks, talk, eat food, etc. all these things are related to the nerves. If there are no nerves present, then there a communication gap will arise. Sometimes, it is thought that the brain is the main component of our body. The brain is controlling the body. But this is not fully a correct statement. The nervous system is a large system where different component plays an important role. The autonomic nervous system is part of the nervous system.

Autonomic Nervous System

The autonomic nervous system is an integral part of the nervous system. They can’t differentiate between the Central Nervous System & Peripheral Nervous System. CNS & PNS are both different things. They are not related to the Autonomic Nervous System or ANS. They come from both CNS & ONS. But their working field is completely different. From the structural purpose, they belong to the CNS & PNS. But they only act upon the smooth muscles & organs.

Sometimes, the Autonomic Nervous System terms as Visceral Nervous System. As this nervous system is associated with the responses from the internal organs. This nervous system can do its work autonomously. This means, there is no need to take any command to execute the proper function. Whenever there is a particular stimulation, it performs certain tasks. ANS can control important body functions without taking help from the Cerebral Cortex. ANS can regulate the stimulation of smooth muscles & organs unconsciously.

👁 Autonomic Nervous System

Anatomy of the Autonomic Nervous System

There is not typically no anatomical structure present. As Autonomic Nervous System is developed with only the help of neurons. There are no other cells present. But still, the Autonomic Nervous System can be divided into three parts.

1. Center: This is the starting point of the ANS. From this part, ANS develops. Depending upon the type or division of ANS, it can be developed from a different area. Like one type is starting from the Thoracic & Lumber region of the Spinal Cord. And another part is coming from the Sacral Region of the Spinal Cord & Brainstem.
2. Ganglia: This is the connecting part of the ANS. The neurons which are coming from CNS or PNS area will be left here. From here onwards there will be Autonomic Fibers which will conduct the messages. This acts as the junction of the neurons. Two different neurons joined here to have better communication. Sometimes in some cases, the neurons which are coming from the CNS or PNS don’t stop at the ganglia. Sometimes they travel to the target organ. There they end their journey.
3. Autonomic Fibers: These are the neurons that are starting from the Ganglia. After ending the neurons that are coming from the CNS or ONS will end at the Ganglia. Instead of that, Autonomic Fiber will take their position. There are two types of fiber. One is Efferent & another is Afferent fiber. Efferent Fibers will transport the messages from the CNS or PNS to the muscles. Whereas the Afferent Fibers transport the messages from the muscles or organs. This will help to make a two-sided communication.

Types of Autonomic Nervous Systems

As per the function of the ANS, scientists have divided them into two parts. These two parts work simultaneously to provide a better communication bridge. All of these divisions have their equal contribution to human actions.

1. Sympathetic Nervous System: This Nervous system arises from the Thoracic & Lumber region of the Spinal Cord. That is why it is often called the Thoracolumbar. This nervous system also has a different name. this name comes from its function. It is often called Fight or Flight.
2. Parasympathetic Nervous System: This Nervous system arises from the Sacral Region of the Spinal Cord & Brainstem. That is why it is often called the Craniosacral. This nervous system also has a different name. this name comes from its function. It is often called Rest or Digest.

Sympathetic Nervous System

This is the first component of the ANS. This nervous system is also known as the Thoracolumbar. As this nervous system developed from the Thoracic & Lumber region of the Spinal Cord. They are also often termed Fight or Flight Nervous Systems. As this nervous system only acts when there is a sudden excitement in the body. It regulates the body component in a very unique way.

Suppose, a human body suddenly feels an excitement there. As soon as it will feel the excitement, SNS will act. It will simply increase the rate of the heartbeat. As well as it will increase the rate of respiration. It will also release glucose for burning & supplying energy sources to the body. On the other hand, it will reduce the work functions of other organs. It also reduces excretion from the human body. This means as per the situation, it will regulate the body components. For this purpose, there is no need to take any command from an organ.

Sympathetic Nervous System - Stimulation The “Fight or Flight” Response

The Sympathetic Nervous System is responsible for the “Fight or Flight” response. As this nervous system is being used there is an excited state. It means an individual is not feeling in a normal condition. Maybe they are in fear or heart. In such cases, the SNS starts providing signals to the organs. Where they start acting in a different form to balance the situation.

At first, the SNS increases the heart rate of the individual. This helps to pump more blood from the heart. Also, SNS increases the respiratory rate of the individual. So that, they can able to inhale more oxygen at that time. As well as, it helps to break down glucose & increase energy levels inside the body. At this point, some relatively less important organs reduce their functions. The function of the digestive system & the urinary system reduces down this time. As they are not necessary at this point. After the situation gets resolved, the PNS helps to make a normal situation.

Parasympathetic Nervous System

This is another component of the ANS. This nervous system is also known as the Craniosacral. As this nervous system is developed from the Sacral Region of the Spinal Cord & Brainstem. Also, this has another name. It is often called the Rest or Digest. This means this nervous system can only able to work when there is no excitement. When the human body is at complete rest, it starts working.

Whenever there is no excitement & the human body is having rest, PNS will work. It will do the opposite tasks of the SNS. This means it will reduce the heart rate & respiratory rate. As there is no need to use those in high value while taking a rest. Also, it will start to store glucose in the liver. Another organ will increase their work rate. Also, the excretion rate will increase by the PSNS. So, depending upon the state, the functions get changed. So, that the human body can easily digest & rest for a while.

Importance of Autonomic Nervous System

Autonomic Nervous System is very important to the human body. It helps to provide reflex action of the human body while in unconsciousness. If a human body feels excited for any reason the ANS will start acting. Without it, a human can’t able to regulate the body's functions properly. It doesn’t provide necessary actions to the organs. Rather, it helps to demonstrate an internal change in the mechanism. The organs will act differently under different conditions. When there is no excitement, then there is a need to reduce the pressure. For that purpose, ANS reduces heartbeat to make a normal situation. In absence of ANS, the human body will not show proper behavior. In the absence or disorder of the ANS will be a life-threatening issue. So, there is no proper word to state the importance of ANS in the human body.

Functions of the Autonomic Nervous System

The function of the Autonomic Nervous System is to maintain proper balance in the human body. SNS helps to contract the smooth muscle cells & PNS dilutes the smooth muscle cells. The same thing goes for the heart muscles also. Mainly SNS & PNS works as contradictory to each other.

But Autonomic Nervous System has some specific actions on different organs or cells. The actions are different from each other. Depending upon the stress & situation, the actions may be witnessed.

1. Function On Eye: SNS helps to dilation of the pupil of the eye. Whenever there is any reason for the excitement it gets enlarged. But for PSNS, the pupil of the eye gets contracted while in the resting situation.
2. Function On Skin: There is no action of PNS on the skin. But the SNS can show up the goosebump & sweating actions on the skin. Whenever there is excitement sweating is a normal condition.
3. Function On Salivary Glands: The SNS will reduce the secretion rate from the salivary gland. On the other hand, the PNS will increase the secretion rate from the salivary gland.
4. Function On Heart: SNS increases heart rate by contracting the muscles of the heart. On the other hand, the PNS reduces the heart rate by enlarging the muscles of the heart.
5. Function On Suprarenal Gland: There is no function of PNS on the Suprarenal Gland. But SNS will increase the rate of secretion of Adrenalin from this gland.
6. Function On Lungs: SNS helps to increase the respiratory rate. It also increases the secretion of the bronchial gland. PSNS helps to decrease the respiratory rate. It also decreases the secretin of the bronchial gland.
7. Function On Blood Vessels: There is no influence of the PNS on the Blood Vessels. But the SNS helps to contract the muscles of the blood vessels to increase the blood pressure during the excitement.
8. Function of Digestive System: SNS helps to inhibit the peristalsis of the stomach. Also, it helps to contract the anal sphincters. On the other hand, the PSNS stimulates peristalsis & digestion. It also helps to relax the anal sphincters.
9. Function On Liver: SNS helps to stimulate the breakdown of glucose to release energy. On the other hand, the PNS helps in the production of glucose to store more energy.
10. Function On Urinary System: SNS helps to decrease urine production. Also, it helps to contract the internal bladder sphincter. On the other hand, PSNS helps to make normal ejection of urine. Also, it relaxes the internal bladder sphincter.
11. Function On Genital System: SNS only stimulates the ejaculation of the Genital system. PSNS helps to make erection of external genitalia.

Clinical Significance

Autonomic Nervous System connects every part of the body. So, damage to this nervous system will create severe problems. Most of the time, the symptoms can be shown at a very late stage. At those times, it will be hard to repair the damages. But still, there is some problem that occurred due to malfunction of the Autonomic Nervous System.

1. Orthostatic Hypotension: This is one type of hypotension. In this disease, there will be a sudden drop in the blood pressure of the patent. Whenever the patient wakes up from the bed or stands up from the chair, the blood pressure will drop. It will provide blurry vision as well as patients can lose their balance. This disease happens when there is a balancing problem between SNS & PSNS.
2. Problem Of Urinary Bladder: Urinary Bladder also provides some symptoms to the damages of SNS & PNS. If SNS is damaged then the urine will involuntarily come out. There will not be any control to hold the urine. And if the PSNS is damaged then there will be a problem to remove the urine. As removing urine in that case is very hard.
3. Impotency: PNS helps with the erection of men & normal libido for women. If PNS is damaged then they will find difficulties. In these cases, the individuals find an inability for an erection & normal libido.

Autonomic Disorders

1. Autonomic Neuropathy: This is a special type of disorder of themic Autonomic Nervous System. In this disease, when nerve cells get damaged. This affects the autonomic body functions. In this disease blood pressure, and digestion might get affected.
2. Multiple System Atrophy: This is a very rare case. In this case, the motor neurons get affected with time. Individuals who are in their 50s might get affected. In this disease, the motor neurons are damaged. And with time, they need to use wheelchairs.
3. Pure Autonomic Failure: This is a serious disease when the total Autonomic Nervous System gets collapsed. This is the final stage of any nervous system disease. In this disease, an individual losses ability to sweat, sudden changes in blood pressure, etc.
4. Dysautonomia: This is a disease that gets from genetic inheritance. In this disease, there is a problem with the development of the nerve cells in the Autonomic Nervous system. In this disease, individual losses the ability to sense pain. Also, in this disease, there is no tear production.
5. Baroreflex Failure: In this disease, the Afferent Nerves get affected. So, in this disease, blood pressure can't be measured. Also, in this disease, the blood pressure changes rapidly.

Question 1: Which gland regulates the Autonomic Nervous System?

Answer:

Hypothalamus is the regulating unit of the Autonomic Nervous System. Though there is no need to take commands from the Hypothalamus to perform necessary tasks. But they are associated with the Hypothalamus.

Question 2: Which action acts as the stimulation for the Autonomic Nervous System?

Answer:

Only stress can act as the stimulation for the Autonomic Nervous System. Stress or excitement will wake up the nervous system. And some opposite tasks will be performed by the organs to have a balance in the body.

Question 3: Which vitamin is needed to help the Autonomic Nervous System?

Answer:

Vitamin D is needed to help Autonomic Nervous System. Scientists believe that Vitamin D can repair or help the Autonomic Nervous Systems in any form.

Question 4: What is the process of stabilizing the Sympathetic Nervous System?

Answer:

The only way to stable the Sympathetic Nervous System is to take a deep breath. Taking a long inhale & a long exhale will help to reduce the stress. This is the only possible way to stable the Synaptic Nervous System.

Question 5: Name some organs where only one division of the Autonomic Nervous System is allowed to work.

Answer:

There are some organs or cells where only one type of Autonomic Nervous System works. Like in Blood Vessels & Skin only Synaptic Nervous System is workable.