Dorothy FarrarParasympathikus
Together with the sympathetic and the enteric nervous system , the parasympathetic forms the autonomic nervous system. A large part of the internal organs and the blood circulation are subject to its control. While the sympathetic nervous system is known as the “fight and flight nerve”, the parasympathetic nervous system is also popularly referred to as the “resting nerve”.
Definition
The parasympathetic is an important part of the autonomic nervous system and the antagonist of the sympathetic. It affects the heart , the blood vessels , the bronchi , the gastrointestinal tract , the gastrointestinal tract, the urinary bladder , the genitals , the eye and the salivary glands .
In contrast to the sympathetic nervous system, the parasympathetic nervous system primarily innervates bodily functions that help the body to recover and create energy reserves. The homeostasis, i.e. the balance in the organism, is also subject to the parasympathetic nervous system. So that all organ functions can run smoothly, there must be a balance between the parasympathetic and sympathetic nervous system.
Anatomy
The vegetative centers and core areas of the parasympathetic nervous system are located in the area of the brainstem and the sacral cord. The segments S1 to S5 of the spinal cord are called the sacral cord . The nerves from the brainstem supply the lacrimal and salivary glands and the inner muscles of the eyes. Cranial nerves III (oculomotor nerve), VII (facial nerve) and IX (glossopharyngeal nerve) carry parasympathetic fibers.
An important part of the parasympathetic nervous system is the vagus nerve, the tenth cranial nerve. It innervates most of the internal organs of the human body. On the other hand, nerves originating from the sacral cord control the lower part of the large intestine , the bladder and the sexual organs. Both innervation areas overlap in the area of the large intestine at the so-called Cannon-Böhm point.
Since some of the parasympathetic root cells are located in the area of the skull (cranium) and the other part in the area of the sacrum (os sacrum), the parasympathetic nervous system is also known as the craniosacral system. The main transmitter substance in the transmission of nerve stimuli is the neurotransmitter acetylcholine in the parasympathetic system.
There are two different types of receptors that respond to the neurotransmitter acetylcholine. Firstly, these are the nicotinic receptors. As the name suggests, they react not only to acetylcholine, but also to nicotine . The muscarinic receptors respond to acetylcholine and, in addition, to muscarine. Muscarine is a fungal toxin.
Nicotine is one of the so-called parasympathomimetics. Parasympathomimetics increase the effect of the parasympathetic nervous system. This explains why smokers primarily reach for a cigarette in stressful situations.
Function
In the heart, the parasympathetic nervous system slows the heart rate and excitability. In addition, excitations in the cardiac conduction system of the heart are passed on more slowly. In medical jargon, this means that the parasympathetic nervous system has a negative dromotropic, negative bathmotropic, and negative chronotropic influence on the heart. In the bronchi , the parasympathetic nervous system increases the secretion of bronchial mucus and narrows the bronchi themselves.
The parasympathetic activity also results in increased secretion in the gastrointestinal tract. Here the digestive glands work harder and produce digestive juices and enzymes. In addition, the peristalsis of the intestine increases. The intestinal movements are called peristalsis. On the one hand, they serve to mix and on the other hand to transport the chyme towards the anus .
During parasympathetic excitation, the detrusor muscle in the bladder contracts. This muscle is also called the urinary expeller because its contraction causes the bladder to empty. At the same time, the bladder sphincter relaxes. This also leads to emptying of the bladder.
In the eye, the effect of the parasympathetic nervous system is reflected in a narrowing of the pupils (miosis). When the salivary glands are parasympathetic, more saliva is produced. While the sympathetic primarily stimulates external activities, the parasympathetic dominates internal body functions such as digestion.
Diseases
- Vagotonics
Dysregulation of the autonomic nervous system is also referred to as autonomic dystonia. If the tension between the sympathetic and parasympathetic nervous system has shifted in favor of the sympathetic nervous system, this is called sympatheticotonia. A sympathicotonic person blushes more easily, often has trembling hands, sweats easily, has a rapid pulse and is more easily aroused, so that he sometimes overreacts to stimuli.
In vagotonia, the influence of the parasympathetic predominates. The vagotonic feels rather weak and weak, suffers from cold feet and hands as well as from dizzy spells up to fainting . Both sympatheticotonia and vagotonia are not actual disorders, but rather the two end poles on a scale. Nevertheless, those affected can suffer from this situation.
The diagnosis of vegetative dystonia is rarely made in practice and is actually a diagnosis of exclusion. Psychosomatic factors are often considered to be the cause, but vegetative dystonia can also have physical causes. If all physical causes have been ruled out, the doctor usually recommends psychotherapeutic treatment as a therapy.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.