10 automatic actions of the nervous system - all listed below are absolute facts, so we read.
The nervous system is a giant network of neurons that transmit signals and the connections between them. Most neurons - 100 billion or so - are found in our brains (the spine is second, with about 1 billion neurons). Moreover, the brain contains more than one type of neurons, there are thousands of them, each has its own shape, function and purpose.
The nervous system consists of two parts, each of which ultimately serves to propagate a signal between neurons:
1) The central nervous system consists of the brain and spinal cord, and acts as the primary organ that controls incoming and outgoing messages from the brain;
2) The peripheral nervous system is the roads, streets and alleys of the main system. It connects the central nervous system to the rest of the body and consists of two parts: somatic (which directs messages back to the central nervous system) and vegetative (which controls the functioning of organs).
Below we will look at 10 basic things that our nervous system processes automatically.
1. Sensory adaptation
Your five senses - touch, sight, hearing, taste, and smell - deliver large amounts of sensory data to your brain for processing. The nervous system in this case serves to highlight the sensory information that is most important.
Special cells called mechanoreceptors play a critical role in this. If you touch your finger and hold it on the clothes that are now on you, then very little time will pass and you will no longer feel anything. Since this does not cause pain, your nervous system stops reading and sending signals about this action. That is, the central nervous system calmed down, because the sensory receptors sent her a signal that everything was fine. Nevertheless, moving your finger to the side, you will again feel that you are wearing clothes, and what the quality of the fabric from which it is sewn is, however, after a few seconds you will again lose sensitivity.
Your nervous system doesn't pay much attention to meaningless, repetitive sounds or noises, such as the hum of a fluorescent light bulb or laptop. However, if any new noise appears, it will immediately grab your attention, because it will disrupt the usual environment. Or, if you come to visit one of your friends, you will immediately smell the smell characteristic of each house, although he or she will claim that they do not smell anything.
2. Heartbeat, pulse and blood pressure
If you measure your heart rate while you sleep, and then after you get up and start walking around the room, you will find that your heart rate will rise. But why is this happening?
Your nervous system controls the heartbeat (about 100, 000 beats per day), as well as the speed at which it beats and the force with which the blood acts on the arteries and veins in your body. Moreover, the work of the central nervous system should be appreciated: with each heartbeat, oxygen-enriched blood is delivered to each cell. Your cells require less oxygen when you sleep, so your nervous system knows to conserve these precious heartbeats. Because of this, the speed of blows and the force with which the heart beats slows down.
The nervous system closely monitors how much oxygen the cells receive, and it takes a few fractions of a second to correct if they are not fully saturated. While you can change your heart rate by changing your level of physical activity, your nervous system actually makes the adjustments. You just "tell" her about the need for more or less oxygen.
3. Sexual arousal and orgasm
The part of your brain responsible for emotions, sensitivities, and thoughts plays a huge role in sexual arousal. Once “activated, ” they usually send a message to the hypothalamus, which then activates the autonomic nervous system. The sympathetic and parasympathetic nervous systems then send many signals to your body that increase your heart rate and blood flow to your penis and clitoris. Increasing blood flow to the vagina increases pressure on the vaginal walls, which triggers the production of lubricant. The nervous system constantly regulates the temperature of the scrotum, by strengthening or weakening its tissues, depending on the body temperature and the environment.
The sympathetic nervous system controls orgasm through increased breathing, increased circulation, sweating, and muscle contractions. After orgasm, the parasympathetic nervous system restores the body to its normal state.
Interestingly, other things, including exercise, stimulate the sympathetic nervous system. One study showed that women became more aroused after watching an erotic movie if they did a set of physical exercises before that. Anxiety also contributes to the appearance of arousal in women, but only on the physical level, that is, at the time when the body is ready for intercourse, the mind is less interested in it than usual.
When the nervous system instructs the digestive system to digest food, a waste product called urea is left in the blood after the process is complete. All blood circulates regularly through the kidneys, which separate urea and other waste products. This waste, along with water, will be diverted to the bladder.
A person produces about 1.4 liters of urine per day. Your bladder can hold at most less than a third of that amount (about 400 milliliters), although usually less, depending on your physical size.
Your nervous system controls your bladder filling throughout the day. The nerves connected to the spinal cord are "attached" to the detrusor muscles located in the bladder wall, as well as to the urethral sphincter muscles. For urination to occur, the detrusor muscles must be tense and the urethral sphincter muscles relaxed.
As it fills, the walls of the bladder stretch, which is what the brain is told. Fortunately, our nervous system temporarily limits the spinal cord reflexes that could trigger immediate, involuntary urination. Instead, the person receives a signal that he needs to go to the bathroom. As with breathing, a person can control the process for some time, but not too long. As time goes on and your body requires more space in your bladder, your CNS gradually eases reflex restrictions.
Probably, the first date would not go well if you and your partner during dinner, before putting another piece of food in your mouth, thought about activating the work of the salivary glands.
Salivation is very important for digestion as it helps lubricate your mouth and esophagus, which is essential for swallowing food. Saliva also initiates the process of breaking down food as soon as it enters the mouth. Saliva production takes place in the salivary glands, and there are three types of glands that produce saliva of different consistency (more or less liquid). Your autonomic nervous system controls both the amount and type of saliva you make.
If you are anxious or scared, you may feel dry mouth. Instead of helping you cry for help, your autonomic nervous system takes fluid from wherever it can, in order to redistribute it to more pressing needs during times of stress.
The dependence of saliva production on the nervous system was first demonstrated in the famous experiments with Pavlov's dog. It's also worth noting that when you're in a stressful situation, your saliva contains more of the stress hormone cortisol.
In order for it to begin, food must be "broken down" into smaller components, which are subsequently used for the needs of the body. This is a surprisingly complex process, especially when you consider that all we do consciously is chew and swallow. Everything else is taken care of by the nervous system.
The nerves that are born in the brain and spinal cord are called external nerves, and it is they that refer to the digestive system on behalf of the nervous system. These nerves "trigger" adrenaline and acetylcholine to work:
- Acetylcholine causes your digestive tract to contract, allowing food to move. This chemical also encourages the stomach and pancreas to produce more stomach acid;
- adrenaline completes the process, relaxes the muscles of the digestive system, and ends the production of gastric juice. This is very paradoxical, since adrenaline also takes part in stressful situations, as far as we know, it makes the body work at increased speed.
Internal nerves are located directly in the tissues of the esophagus, stomach, small and large intestine. They react to stretching and the release of chemicals that regulate the rate of digestion and the secretion of digestive juices. These internal nerves form their own nervous system, containing a similar number of neurons to the spinal cord.
7. Adrenaline and stress
Although our autonomic nervous system most often does everything right, sometimes unforeseen situations occur, one of them is its reaction to the moment of stress (adrenaline rush, etc.). However, this gives us the opportunity to go on superhuman feats, but at the same time, we can often perceive, for example, public speaking as an existential threat.
When we are stressed or anxious, we feel heightened anxiety, which can include shaking, dry mouth, sweating, and even distorting our vision. While we often associate this feeling with a state of fear or vulnerability, in fact, at such times we are fully prepared to take decisive action.
This condition is based on the action of the adrenal glands, two tiny glands located just above the kidneys. Several neurons located in these glands work as part of the sympathetic nervous system. When a person is faced with an emergency, the nervous system asks the adrenal glands to release some adrenaline into the bloodstream.
This hormone provokes many changes to take effect quickly:
- the heartbeat becomes faster and stronger, which raises blood pressure;
- the level of sugar in the blood rises;
- there is a redistribution of resources, which contributes to more rapid blood clotting;
- pupils dilate, which allows you to see the threat in full;
- the bronchi expand, as they prepare the body to consume oxygen in the maximum amount.
When the threat is eliminated, the adrenal glands are given a signal to stop the release of adrenaline, and they produce another hormone that neutralizes all the consequences.
8. Respiration and lung function
If you think it’s hard to constantly remember to remove your cup of coffee from the dashboard of your car before driving off, then you should be glad that you don’t have to remember that you have to breathe every few seconds. so as not to die.
It's not that your nervous system "considers" you completely irresponsible, no, because breathing is one of those things that the central nervous system monitors, however, to a certain extent, sometimes a person can lead this process. However, the boredom, which will certainly overcome you if you monitor your breathing regularly, will force you to re-entrust this matter to the nervous system again.
You can try to suppress your breathing, however, you will have limited success in this endeavor. Your nervous system has placed sentinels to monitor the level of carbon dioxide in your blood. If these specialized cells, known as peripheral chemoreceptors, don't like what they see, they immediately send a signal to the brain. Having received the appropriate signals, the brain instructs the diaphragm and other muscles associated with this process to actively contract. Satisfied that the carbon dioxide level has decreased, the chemoreceptors calm down until the next time.
Your lungs, however, contain another group of sentinels. If these receptors feel like the lungs are overloaded, they will ask the brain for approval to help them. But in truth, all these messages can be nothing more than playing with a broken phone, so this confusion in signals often leads to a disordered breathing pattern - hiccups.
9. Pupil dilation
If you've ever stared at a light bulb for a long time before you suddenly turned it off, you will no doubt find yourself in a short period of visual disorientation immediately afterwards until your eyes become accustomed to the dark environment. After a minute or so, you can already see much less light, but you can see much more clearly. We take many things for granted, and one of them is our ability to see.
In order for a person to see, light must first enter the pupil, which is approximately 3-5 millimeters in diameter. The amount of light that enters the pupil is of great importance for the quality of our vision. For example, too much light on a sunny day will blind us, too little light in a darkened room leads to the fact that we cannot see certain things well.
Our nervous system constantly monitors the amount of light entering our eyes. She also monitors how effective a particular amount of light is for us to see certain objects. When it is dark, our pupils dilate to "let in" more light, possibly thereby improving our vision of our surroundings, when there is too much light, the pupils, on the contrary, narrow to limit the light exposure to the eyes.
If you want to visually see the work of your autonomic nervous system, go to the mirror, close your eyes and after a while open them, so you will see the changes that have occurred with your pupils.
No one thanks the nervous system after he feels he is sweating a lot. However, if it were not for your body's ability to take action during extreme heat, each of these hot days could end with a fatal heatstroke for you.
Without any help from you, your body diligently maintains water balance in every cell and maintains the required temperature. When it needs to release some heat, it does so in the form of perspiration with the help of 2.6 million sweat glands. We always sweat, although sweat (a mixture of water, chlorine, sodium and potassium) is often reabsorbed by the sweat glands before it reaches the surface of the skin.
Thus, it is simply water evaporated from the surface of the skin that removes excess heat from the body. But what if this excess heat is not there? The nervous system is still preparing your body for possible sudden increases in temperature.
And finally, a detailed picture of the relationships: