Question to the brain
What is the Autonomic Nervous System?
Published: 16.06.2024
Why do we actually need an autonomic nervous system? Isn't one nervous system enough for everything?
The editor's reply is:
Prof. Dr. med. Janne Gierthmühlen, Interdisciplinary Pain and Palliative Care Clinic, Department of Anesthesiology and Operative Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel Campus: The Autonomic nervous system plays a crucial role in our daily lives by controlling many vital functions without us being aware of it. It regulates our heartbeat and breathing and controls how our digestive system works. This automatic control allows us to concentrate on other tasks without having to constantly think about these basic processes.
An impressive example of the importance of the autonomic nervous system is the “fight-or-flight” response. Imagine you suddenly find yourself face to face with an aggressive dog. Your heart starts beating faster, your muscles tense up, and your breathing quickens. This response is triggered by the autonomic nervous system to prepare the body for a quick escape or fight. In life-threatening situations, this involuntary response can mean the difference between life and death.
The autonomic nervous system consists of two main parts: the sympathetic and parasympathetic nervous systems. The sympathetic part is known for its role in stress and emergency situations, while the parasympathetic part supports the body during periods of rest and recovery.
Anatomically, the autonomic nervous system consists of a network of nerves that run from the brain and Spinal cord to various organs in the body.
It uses various neurotransmitters to transmit signals. The most important neurotransmitters are Acetylcholine and norepinephrine. Acetylcholine is mainly used by the parasympathetic system to promote relaxation and digestion. Norepinephrine, on the other hand, is released by the sympathetic system to put the body on alert.
An example of the function of the Sympathetic nervous system is the increase in heart rate and the dilation of the bronchi in the lungs during physical activity or stress. These reactions enable better oxygen supply to the body and prepare it for increased performance. The parasympathetic part, on the other hand, reduces the heart rate and promotes digestion by increasing the activity of the gastrointestinal tract. In this way, it ensures relaxation and regeneration after stressful events.
In summary, the autonomic nervous system is a complex and vital system that regulates many unconscious bodily functions. It consists of two opposing systems, the sympathetic and parasympathetic nervous systems, which work closely together to keep the body in balance. Without the autonomic nervous system, we would not be able to react to sudden dangers or recover after strenuous activities. It is the unconscious conductor in the body that ensures that all vital processes run harmoniously.
Recorded by Johanna Rümenapp
Autonomic nervous system
The part of the nervous system that primarily controls unconscious vital functions such as breathing, heartbeat, and blood pressure. The autonomic nervous system is divided into the sympathetic nervous system, which is active in performance and stress situations, and the parasympathetic nervous system, which is active during rest and recovery phases. In some cases, the enteric nervous system, which is responsible for gastrointestinal functions, is also considered part of the autonomic nervous system.
Spinal cord
medulla spinalis
The spinal cord is the part of the central nervous system located in the spine. It contains both the white matter of the nerve fibers and the gray matter of the cell nuclei. Simple reflexes such as the knee-jerk reflex are already processed here, as sensory and motor neurons are directly connected. The spinal cord is divided into the cervical, thoracic, lumbar, and sacral spinal cord.
Acetylcholine
Acetylcholine is one of the most important neurotransmitters in the nervous system. In the central nervous system, it is involved in attention, learning, and memory; in the peripheral nervous system, it transmits excitation from nerves to muscles at the neuromuscular end plates and controls processes of the autonomic nervous system, i.e., the sympathetic and parasympathetic parts. Areas in which acetylcholine acts as a messenger substance are called cholinergic. It was the first neurotransmitter to be discovered, identified in 1921 by Otto Loewi in the heart of a frog.
Sympathetic nervous system
Part of the autonomic nervous system, whereby the sympathetic nervous system primarily transmits excitatory impulses – in contrast to its counterpart, the parasympathetic nervous system. For example, the sympathetic nervous system activates respiration, the heart, and circulation, but it also affects the smooth muscles of all internal organs. The sympathetic nervous system uses the neurotransmitters acetylcholine and norepinephrine.