Anatomical and physiological features
The nervous system is laid down on the 2nd week of intrauterine development, when the total length of the embryo does not exceed 2 mm. The greatest intensity of the division of nerve cells of the brain falls on the period from the 10th to the 18th week of intrauterine development. It can be considered a critical period in the formation of the CNS. Later, accelerated division of glial cells begins, which continues until the age of 2 years. If the number of nerve cells in the brain of an adult is taken as 100%, then by the time the child is born, only 25% of the cells have been formed, by 6 months of age they will already be 66%, and by 1 year – 90-95%.
As the nervous system develops, the chemical composition of the brain also changes significantly. First of all, this refers to a decrease in water content, an increase in the content of lipoproteins. The latter concerns only the white matter of the brain and reflects the processes of myelination occurring in it.
The incompleteness of the process of myelination of nerve fibers determine the relatively low rate of conduction of excitation through them.
Different parts of the brain also have their own patterns of timing and pace of development. The development of the cerebral cortex proceeds most intensively in the last months of the intrauterine period and in the first months after birth, however, the full development of the cell structures of the cerebral hemispheres is completed only by 10-12 years of age. The end of the formation of the cerebellum occurs by the 2nd year of life, the hypothalamus – in puberty. Large furrows and convolutions are very well expressed, but have a shallow depth. There are few small furrows, they appear only in the first years of life.
The spinal cord is actively developing. By the age of 2, its structure is almost the same as that of an adult. The length of the spinal cord increases somewhat more slowly than the length of the spine, so the lower end of the spinal cord moves upward with age. This should be taken into account when choosing the level of spinal puncture.
The blood supply to the brain in children is better than in adults. Abundant blood supply to the brain provides the need for rapidly growing nerve tissue in oxygen.
The substance of the brain is very sensitive to increased intracranial pressure, which leads to a rapid increase in degenerative changes in nerve cells, up to atrophy. Therefore, the development of hydrocephalus or microcephaly is important to diagnose in the first months of a child’s life.
Development of the sensory sphere
Skin sensitivity. Newborns are immediately sensitive to pain, but their pain threshold is much higher than that of older children and adults. Particularly low pain sensitivity is noted in premature and adult children.
Thermoreception is presented in newborns in a morphologically and functionally completed form. There are almost 10 times more cold receptors than heat receptors, and therefore the child’s sensitivity to cooling is significantly higher than to overheating.
Vision. By the time the child is born, the development of the eye itself and the visual analyzer has not yet been completed. For the final formation of the organ of vision, stimulation with a light stimulus is necessary. A newborn child is characterized by moderate photophobia, his eyes are almost constantly closed, the pupils are constricted. The lacrimal glands do not function. By the age of 2 weeks, a transient fixation of the gaze occurs, and the secretion of the lacrimal glands appears.
The question of the perception and discrimination of colors in young children has not been finally resolved; already from 1.5-2 years old, a child can pick up 2-3 objects of a similar color. Subsequently, the perception of color shades improves and after 3 years all children have sufficiently developed color vision.
vestibular apparatus . The newborn baby hears. Sounds of a sufficiently large force are perceived even by the fetus. The reaction of a newborn and premature baby to sound is expressed in general motor restlessness, screaming, changes in the frequency and rhythm of heartbeats or breathing.
Taste. The taste threshold of a newborn is higher than that of an adult. The reaction to sweets is always expressed in calming and sucking movements, and to all other taste sensations – the same type of negative (wrinkling, general anxiety, sometimes vomiting.
Smell. Receptor cells are located in the mucous membrane of the nasal septum and superior nasal concha. The olfactory senses begin to function sufficiently between the 2nd and 4th months, when the child reacts to pleasant or unpleasant odors. Differentiation of complex odors improves up to primary school age.
Characteristics of a newborn baby
Unconditioned reflexes . A child is born with a number of unconditioned reflexes, which are divided into three main groups.
Persistent lifelong automatisms (corneal, conjunctival, pharyngeal, swallowing, tendon reflexes of the extremities, orbiculopalpebral reflex).
Transient rudimentary reflexes, reflecting the specific conditions of the level of development of the motor analyzer and subsequently disappearing:
sucking reflex – if you put a pacifier in the baby’s mouth, then he begins to make sucking movements. The reflex disappears by the end of the 1st year of life;
search reflex – when stroking the skin in the area of u200bu200bthe corner of the mouth, the lips are lowered, the tongue is deflected and the head is turned towards the stimulus. The reflex is especially well expressed before feeding. Disappears by the end of the 1st year;
Babkin’s palmar-mouth reflex – is caused by pressing the thumb on the child’s palm near the tenors. The response is opening the mouth and bending the head. Disappears by 3 months;
Robinson’s grasping reflex – the child grasps and firmly holds a finger placed in his palm. The same reflex can be evoked from the lower extremities if you press on the sole at the base of the 2nd or 3rd fingers, which will cause plantar flexion of the fingers. Disappears on the 2nd-4th month;
Moro reflex – lift the child by the arms so that the back of the head is in contact with the surface of the table, quickly lower it. In response, the child first moves his hands to the sides and opens his fingers (1st phase), and then after a few seconds returns his hands to their original position (2nd phase), while the arms seem to cover the body. The reflex lasts up to 4 months;
protective reflex – if a newborn is placed face down on his stomach, his head turns to the side;
support reflex and automatic walking – the child is taken by the armpits from the back, supporting his head with his thumbs. Placed on a support, he leans on it with a full foot, “stands” on half-bent legs, straightening his torso. With a slight tilt of the torso forward, the child makes step-by-step movements on the surface. The reflex disappears by the 2nd month;
Bauer crawling reflex – the child is placed on the stomach so that the head and torso are located on the same line, and a palm is placed under its soles. In this position, the child raises his head for a few moments, pushes off the support with his feet and makes movements that imitate crawling. Disappears by 4 months;
Galant reflex – irritation of the skin when running the thumb and forefinger along the paravertebral lines in the direction from the neck to the buttocks leads to the bending of the body in an arc open towards the stimulus. Disappears by 4 months;
Perez reflex – if a child lying on the researcher’s hand holds a finger from the coccyx to the neck, slightly pressing on the spinous processes of the vertebrae, then he raises the pelvis, head, bends his arms and legs, screams. This reflex causes pain, so it is tested last. Disappears by 4 months.
Reflexes, or automatisms, only appearing and therefore not always detected immediately after birth (adjustment labyrinth reflexes, simple chain neck and trunk adjustment reflexes).
Emotions. Exceptionally negative in nature, rather monotonous (shout) and always rational, as they serve as a reliable signal of any trouble, both in the internal and external environment for the child. The mother, being perfectly oriented in the current situation, in the vast majority of cases is able to return the necessary comfort to the child – to feed, turn over, change wet or unsuccessfully placed diapers, etc.
Assessment of neuropsychic development
The level of neuropsychic development is determined using special assessment tables (different for children of the 1st, 2nd and 3rd years of life) according to certain indicators (lines) of development.
Eight lines are evaluated in the 1st year of life:
visual orienting reactions (vision analyzers Az);
Auditory orienting reactions (Ac);
Hand movements and actions with objects (Dr);
General movements (Before);
understandable speech (PR);
active speech (Ar);
Skills and skill in processes (N).
In the 2nd year of life, six leading lines are evaluated:
understanding of speech (PR);
active speech (Ar);
sensory development (C);
· game of action with objects (Eid);
In the 3rd year of life, five leading lines are evaluated:
active speech (grammar, questions) (Ar);
sensory development perception of light (C);
story game (I);
skills in dressing (N);
Up to 1 year – 1 month
1-2 years – 3 months
2-3 years – 6 months
Using the age model of normal development, it is possible to determine the level and harmony of the child’s mental development. For this you need:
1) determine if there is a delay along the leading lines of development;
2) find the indicator with the greatest delay (according to the epicrisis period). According to it, determine the group of NPR: Group I – children with advanced and normal development; II, III, IY groups – children with a delay of 1, 2, 3 epicrisis periods, respectively;
3) determine whether the delay is uniform and, if it is uniform, set the degree: I degree – delay of 1-2 indicators, II degree – delay of 3-4 indicators; III degree – a delay of 5-7 indicators;
4) if the delay is uneven, i.e. 1 or 2 indicators lag behind by 1 epicrisis period, and others by 2 or more, this indicates the inharmoniousness of the CPD.
A preliminary assessment of the CPD is carried out by a nurse using tables. The doctor controls her work.
1-children with leading and norms. development
2 children with a delay of 1 epic. term
3-children with a delay of 2 epic. deadline
4 children with a delay of 3 epic. deadline