It is not easy to imagine the structure of the nervous system for a person who has nothing to do with medicine or biology. But surely 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 with all tissues and parts of the body and coordinates their interaction.
Function of autonomic reflexes
Thanks to the spinal nerves, the spinal cord transmits information about the state of the internal and external environment to the brain and vice versa. There is a close connection between the central and peripheral nervous systems, which ensures the functioning 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 vegetative reflexes are characteristic of multicellular organisms,having a nervous system.
Reflex arc
Special receptors - proprioceptors - are located 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. This two-way flow of impulses is called a reflex arc. Reflexes of the autonomic nervous system occur automatically, that is, they are not controlled by consciousness.
Reflex arcs are recognized in the peripheral nervous system:
• vegetative reflexes - neural chains of internal organs: liver, kidneys, heart, stomach, intestines;
• somatic reflexes - neural circuits covering skeletal muscles.
The most common reflex arc of the somatic vegetative reflex is formed with the help of two neurons - motor and sensory. It includes, for example, the knee jerk. Often more than 3 neurons are involved in the reflex arc - motor, sensory, and intercalary. 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 autonomic reflex allows a person to automatically respond to external stimuli, for example, pull his hand away from the source of pain, change the size of the pupil, as a reaction to the brightness of the light. She also contributesregulation of processes occurring inside the body.
Involuntary movements
We are talking about normal spinal autonomic reflexes without the participation of the cerebral cortex. An example would be touching a hand to a hot object and pulling it back abruptly. 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. An example of this are unconditioned reflexes: coughing, sneezing, blinking, flinching. Movements associated with the manifestation of feelings usually have an involuntary character: with strong anger, involuntary clenching of teeth or clenching of fists; genuine laughter or smile.
How reflexes are subdivided
The following classifications of reflexes are distinguished:
- according to their origin;
- view receptor;
- biological function;
- difficulties in constructing a reflex arc.
There are a lot of species, they are classified as follows.
1. By origin, they distinguish: unconditional and conditional.
2. According to the receptor: exteroceptive, which include all the senses; interoceptive, when receptors of internal organs are used; proprioceptive using receptors in muscles, joints and tendons.
3. By efferent links:
- somatic - skeletal muscle reactions;
- vegetative reflexes - reactions of internal organs: secretory, digestive, cardiovascularvascular.
4. According to their functions, reflexes are:
- protective;
- sexual,
- indicative.
To implement vegetative reflexes, the continuity of all links of the arc is required. Damage to each of them leads to the loss of the reflex. With the transformation of the surrounding world during life, conditioned reflex connections are formed in the cortex of the human hemispheres, 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 stimuli from the environment and adapt to new conditions of existence. During this period, sucking and swallowing reflexes are the most important, as they satisfy the most important need of the newborn - nutrition. They occur as early as the 18th week of fetal development.
Newborn reflexes
If a baby is given a pacifier or fist, he will suckle even if he 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 breast. This is a searching reflex. It does not need to be specially called: every time it appears when the baby is hungry, and the mother is going to feed him. If a newborn is placed on his tummy, he will definitely turn his head to the side. This is a protective reflex. Parentsit is well known how the baby grabs and holds an object placed in his palm. Such a reflex grasping of an object is a manifestation of a grasping reflex. A real, conscious grasp of objects will appear a little later - at 3-4 months.
There is an interesting reflex called - palmar-mouth, or Babkin's reflex. It consists in the fact that if you press your finger on the baby's palm in the area of \u200b\u200bthe thumb, he will open his mouth.
Automatic crawling and walking of babies - a kind of reflexes
A baby of the first three months is able to crawl unconsciously. If you put him on his tummy and touch the soles with your palm, he will try to crawl forward. This is the automatic crawl reflex. It lasts up to 2-3 months, and the ability to crawl consciously in the baby will appear later. If the baby is taken from behind under the armpits, supporting his head with his index fingers, and touching his feet to the surface of the table, he will straighten his legs and stand with his feet on the table. 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.
Acquaintance with some of the autonomic reflexes that the baby has from birth will help parents 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 child's reflexes, they shouldremember 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 will not 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 used by medical professionals as a useful addition to official treatment. One of these methods is reflexology. This ancient method of foot massage lies in the fact 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 unblock energy along certain nerve rays penetrating the body, associated, for example, with back pain.
Many patients claim that this massage causes relaxation, and as a result, it relieves tension and gives an analgesic effect. However, the theoretical foundations of reflexology have not been seriously studied, and most doctors doubt its serious healing effect.
