Presenting the structure of the nervous system to a person who is not related to medicine or biology is not easy. But most likely, most people know that there is a central nervous system to which the brain and peripheral nervous system belong. It consists of the spinal cord, which, with the help of nerves, is connected to all tissues and parts of the body and coordinates their interaction.
Autonomic reflex function
Thanks to the spinal nerves, the spinal cord transmits information about the state of the internal and external environment to the brain and in the opposite direction. There is a close connection between the central and peripheral nervous systems , which ensures the work of the whole organism as a whole.
The term "reflex" comes from the Latin word reflexus - reflected - the reaction of any organism to a specific effect, with the participation of the nervous system. Such somatic and autonomic reflexes are characteristic of multicellular organisms having a nervous system.
Reflex arc
Special receptors - proprioceptors - are found in muscles, tendons, ligaments, periosteum. They continuously send information to the brain about the contraction, tension and movement of different parts of the musculoskeletal system. The central nervous system, continuously processing information, sends signals to the muscles, causing them to contract or relax, maintaining the desired posture. Such a two-way flow of pulses is called a reflex arc. Reflexes of the autonomic nervous system occur automatically, that is, are not controlled by consciousness.
In the peripheral nervous system, reflex arcs are recognized:
• autonomic reflexes - neural chains of internal organs: liver, kidneys, heart, stomach, intestines;
• somatic reflexes - neural chains covering the skeletal muscles.
The most common reflex arc of the somatic autonomic reflex is formed using two neurons - motor and sensory. This includes, for example, the knee jerk. Often more than 3 neurons are involved in the reflex arc - motor, sensory, and intercal. It occurs when a finger is pricked with a needle. This is an example of a spinal reflex; its arc passes through the spinal cord without affecting the brain. Such an arc of the vegetative reflex allows a person to automatically respond to external stimuli, for example, to pull the hand away from the source of pain, to change the size of the pupil, as a reaction to the brightness of light. It also helps to regulate the processes occurring inside the body.
Involuntary movements
We are talking about normal spinal vegetative reflexes without the participation of the cerebral cortex. An example is the touching of a hand on a hot object and its sharp withdrawal. In this case, the impulses go along the sensory nerves to the spinal cord, and from there along the motor neurons immediately back to the muscles. Unconditioned reflexes are an example of this: coughing, sneezing, blinking, shuddering. The movements associated with the manifestation of feelings are usually of an involuntary nature: with severe anger, involuntary clenching of the teeth or clenching of the fists; sincere laugh or smile.
How reflexes are divided
The following classification of reflexes are distinguished:
- by the method of their origin;
- type of receptor;
- biological function;
- the complexity of building a reflex arc.
There are a lot of species, they are classified as follows.
1. By origin distinguish: unconditional and conditional.
2. According to the receptor: exteroceptive, which include all sensory organs; interoceptive when internal organ receptors are used; proprioceptive using receptors for muscles, joints and tendons.
3. By efferent links:
- somatic - skeleton muscle reactions;
- vegetative reflexes - reactions of internal organs: secretory, digestive, cardiovascular.
4. According to their functions, reflexes are:
- protective;
- genital
- indicative.
For the implementation of autonomic reflexes, the continuity of all parts of the arc is required. Damage to each of them leads to the disappearance of the reflex. With the transformation of the world around us throughout life in the cortex of the human hemispheres, conditioned reflex connections are formed, the system of which is the basis of most habits and skills acquired during life.
Nervous system in children
When compared with other body systems, the baby’s nervous system at the time of birth is the most imperfect, and the baby’s behavior is based on innate reflexes. In the first months of life, most of the vegetative reflexes help the baby respond to environmental stimuli and adapt to new conditions of existence. During this period, sucking and swallowing reflexes are the most important, since they satisfy the most important need of the newborn - in nutrition. They occur already at the 18th week of fetal development.
Newborn Reflexes
If the baby is given a pacifier or cam, it will suck, even if it is not hungry. If you touch the corner of the baby’s lips, he will turn his head in this direction and open his mouth in search of his mother’s chest. This is a search reflex. It does not need to be called on purpose: every time it manifests itself when the baby is hungry, and the mother is going to feed him. If you put the newborn on the tummy, he will certainly turn the head to the side. This is a protective reflex. Parents are well aware of how the baby captures and holds an object laid in his palm. Such a reflex girth of an object is a manifestation of a grasping reflex. A real, conscious capture of objects will appear in him a little later - in 3-4 months.
There is an interesting reflex called - palmar-oral, or Babkin's reflex. It consists in the fact that if you press with your finger the palm of the baby in the thumb, he will open his mouth.
Automatic crawling and walking babies - a kind of reflexes
The baby of the first three months is able to creep unconsciously. If you lay it on your tummy and touch your soles with your palm, it will try to crawl forward. This is an automatic crawl reflex. It lasts up to 2-3 months, and the baby’s ability to crawl consciously appears later. If the baby takes armpits from behind, supporting his head with index fingers, and touches his feet to the table surface, he will straighten his legs and stand on the table with his feet. If at the same time tilt forward a little, he will try to walk, while his hands remain motionless. This is a reflex of support and automatic walking, which disappears at the age of three months.
Familiarity with some autonomic reflexes that the baby owns from birth will help parents to notice deviations in neuropsychic development and consult a doctor. This is especially true for premature babies, their unconditioned reflexes can be weakened. If parents want to test some of their baby’s reflexes, you should remember that this can be done when he is awake and in a good mood, some time after feeding. It should also be remembered that the baby’s nervous system is characterized by increased fatigue, so he won’t open his mouth, crawl or walk many times in a row at the request of his parents.
Reflexology
Many methods of alternative medicine are now being used by doctors as a useful complement to official treatment. One of these methods is reflexology. This ancient method of foot massage is that on them, as well as on the hands, there are reflex points associated with the systems of internal organs. According to reflexologists, directed pressure on these points can relieve tension, improve blood flow and release energy along various nerve rays that penetrate the body, associated, for example, with back pain.
Many patients claim that such a massage causes relaxation, and as a result relieves stress and gives a painkiller effect. However, the theoretical foundations of reflexology have not been seriously studied, and most doctors doubt its serious healing effect.