Protective blinking reflex R.: contraction of the circular muscle of the eye, for example. with sudden illumination of the eye or the appearance of an object in front of the eyes.

Big Medical Dictionary. 2000 .

See what the "blinking reflex" is in other dictionaries:

Reflex blinking- Blinking reaction in response to irritation with light, sound and other sensory stimuli (touching the cornea or eyelashes, waving a hand in the face of the subject, tapping in the glabella, electrical stimulation of the supraorbital ... ... Encyclopedic Dictionary of Psychology and Pedagogy

I Reflex (Latin reflexus turned back, reflected) is the reaction of the body that ensures the emergence, change or cessation of the functional activity of organs, tissues or the whole organism, carried out with the participation of the central nervous ... ... Medical Encyclopedia

BLINK REFLEX- Reflexive eyelid closure caused by bright light, sudden noise, wind blowing, etc. This reflex has been extensively studied in studies of classical conditioning... Explanatory Dictionary of Psychology

Facial nerve ... Wikipedia

Reactions to the body (reflexes), produced under certain conditions during the life of a person or animal on the basis of congenital unconditioned reflexes. The term "conditioned reflexes" was introduced by I.P. Pavlov. Unlike unconditioned reflexes ... ... Medical Encyclopedia

- (nervi craniales; synonym for cranial nerves) nerves extending from the brain or entering it. There are 12 pairs of C. n., which innervate the skin, muscles, glands (lacrimal and salivary) and other organs of the head and neck, as well as a number of organs ... ... Medical Encyclopedia

FLASHING- BLINK, a reflex to irritation of the sensitive branches of the trigeminal nerve (cornea, conjunctiva, skin surrounding the eye, eyelashes) or to light irritation. Centripetal arc of the reflex t. either trigeminal or optic nerve. ... ... Big Medical Encyclopedia

K. o. called tzh conditioned reaction, conditioned reflex, conditioned reaction and conditioned reflex. I. P. Pavlov was the first to extensively explore its features. The huge work carried out in Pavlov's laboratory showed that ... ... Psychological Encyclopedia

FLASH, ayu, aesh; incompatibility 1. The same as blinking. M. eyes. Significantly m. neighbor. 2. (1st person and 2nd person not used), trans. Flickering, flickering (colloquial). A light flickers in the distance. | one-time blink, well, nosh. | noun blinking, i, cf. | adj… … Explanatory dictionary of Ozhegov

LASER RADIATION- forced (by means of a laser) emission of portions of quanta of electromagnetic radiation by atoms of matter. The word laser is an abbreviation formed from the initial letters of the English phrase Light Amplification by Stimulated Emission of Radiation (amplification ... ... Russian encyclopedia of labor protection

In the position of the newborn on his back, when his lower limbs are relaxed, a needle prick is alternately applied to each sole. There is a simultaneous flexion of the hips, shins and feet. The reflex must be called equally on both sides (symmetrical). The reflex can be weakened in children born in the breech presentation, with hereditary and congenital neuromuscular diseases, myelodysplasia. A decrease in the reflex is often observed with paresis of the legs. The absence of a reflex indicates damage to the lower parts of the child's spinal cord. Cross reflex of extensors.

In the position of the newborn on the back, we unbend one leg and inflict an injection in the area of ​​\u200b\u200bthe sole - in response, the extension and slight adduction of the other leg occur. In the absence of a reflex, pathology of the lumbar thickening of the spinal cord can be assumed.

Tonic neck reflexes or postural reflexes

Types of postural reflexes of a newborn child:

• 1. Asymmetric cervical tonic reflex (Magnus-Klein). It manifests itself when the child's head is passively turned to the side. There is an extension of the arms and legs on the side to which the child's face is turned, and the bending of the opposite. The hand to which the baby's face is turned straightens. At this moment, the tone of the extensors of the shoulder, forearm, and hand increases - the “swordsman” position, and in the muscles of the arm, to which the back of the head is facing, the tone of the flexors increases.
• 2. Symmetrical tonic neck reflexes

With passive flexion of the head of a newborn child, the muscle tone of the flexors in the arms and extensors in the legs increases. At the same time, when the baby unbends his head, the opposite effect appears - the arms unbend and the legs bend.

Asymmetric and symmetrical neck reflexes of the newborn are constantly expressed in newborns. In premature babies, they are poorly expressed. Landau reflex

Give the child a “swimmer position” - lift the baby into the air so that his face looks down, and he immediately raises his head, and then straightens (or even arches) his back, and also unbends his legs and arms - swallow, from 6 months to a year and a half. 1. asymmetric cervical topical Magnus-Klein reflex

• 2. symmetrical neck tonic reflexes
• 3. tonic labyrinth reflexes
• 4. Landau reflex

These reflexes normally disappear in the first 2-3 months. So, as the unconditioned and cervico-tonic reflexes fade, the child begins to hold his head, sit, stand, walk, and carry out other voluntary movements. A delay in the regression of tonic reflexes (over 4 months) indicates damage to the central nervous system of the newborn. The remaining tonic reflexes impede the further development of the child's movements, the formation of fine motor skills.

In recent years, they have been talking about the presence of a swimming reflex in a newborn, which consists in the fact that the baby will flounder and not drown if it is lowered into the water. This reflex can only be tested in the presence of an instructor in the neonatal pool.

Problems with reflexes are the first symptoms of the pathology of the central nervous system. If you are alerted by any deviations from the norm, then do not hesitate to consult a doctor. A re-examination must necessarily take place after the appointed time - it may vary depending on the alleged nature of the pathology - from several days to a month, which will help to eliminate the suspicions or, if necessary, to conduct timely treatment. Remember that the child changes every day, and the manifestation of reflexes depends on a number of conditions (satiety, fatigue, and many others). It is very important to check innate reflexes in dynamics. Timely treatment is the key to the health of the child in the future.

Functions: 1.regulates the work bodies, ensuring their coordinated work;

2.provides accommodation organism to environmental conditions(and information comes through the senses).

Parts of the nervous system:

central part(CNS)- This is the spinal cord and brain;

peripheral- nerves and ganglions.

Departments of the Nervous System:

Somatic(from Greek soma - body) - controls the work of skeletal muscles (controlled by consciousness and will).

Vegetative / Autonomous- Regulates metabolism, the functioning of internal organs and the functioning of smooth muscles.

- its work does not depend on our desires (we cannot intentionally stop or increase the work of the heart, blush or turn pale (some people succeed, but after a long workout and in an indirect way). Intervene in the work of internal organs, regulated by the autonomic nervous system, stop illness, it is impossible to overcome alcoholism and drug addiction without medical assistance).

Rice. Nervous system:

1 - brain;

2 - spinal cord;

4 - nerve nodes.

Reflex is the simplest form of neural regulation.

There are reflexes in both the somatic and autonomic parts of the nervous system. .

The reflex is based chain of neurons or reflex arc.

5 links reflex arc Unconditioned / Innate reflex somatic department N.S. :

1. Receptor are nerve formations that perceive and transform irritation into nerve impulses →

2. Sensitive Neuron (their bodies are in nerve nodes) - perceives stimuli through receptors .

Nerve impulses arising from stimulation are transmitted by dendrite→into the body sensory neuron→ along the axon into the brain→

3. on Interneurons - their processes do not extend beyond the central nervous system / CNS(brain and spinal cord) - processing of received information→

4. after, the signals are transmitted Executive / motor neurons, whose nerve impulses cause work →

5. body .

(Example: Blinking reflex, Patellar reflex, Salivation reflex, Hand withdrawal from a hot object).

5 Links of the Reflex Arc of the Blinking Reflex

Getting a blink flax reflex and condition defiant its inhibition :

When touched inner corner eyes - involuntary blinking of both eyes.

In Fig. 1, the reflex arc of this reflex.

The circle is the part of the medulla oblongata where the centers of the blinking reflex are located. The bodies of sensory neurons 2 lie outside the brain in the ganglion.

Irritation of receptors → the flow of nerve impulses directed by dendrite To body sensory neuron 2 and from it axon V medulla oblongata. There's excitement through synapses transmitted intercalary neurons 3. Information is processed by the brain, including the cortex. We after all felt a touch to a corner of an eye! → then the executive neuron 4 is excited, the excitation along the axon reaches the circular muscles of the eye 5 and causes blinking. Let's continue monitoring.

But, if you touch the inner corner of the eye several times - reflex slowed down.

When answering, it should be taken into account that along with direct connections, according to which the "orders" of the brain go to the organs, there are feedback carrying information from organs to the brain. Since our touches were not dangerous for the eye, after a while the reflex faded.

A completely different result would have been if a speck had got into the eye. Disturbing information would reach the brain and increase the response to irritation. In all likelihood, we would try to extract the mote.

By force of will it is possibleslow down blink reflex:

To do this, touch with a clean finger to the inner corner of the eye and try not to blink. Many succeed. Impulses from the cortex, slowed down the nerve centers of the medulla oblongata - this central braking , discovered by a Russian physiologist Sechenov: « Higher Centers of the Brain able to regulate workLower Centers : enhance or inhibit reflexes.

Spinal knee jerk: cross your legs. Relax the muscles in your outstretched leg. With the edge of your hand, hit the tendon of the quadriceps muscle of the thrown leg. The leg should bounce. Don't be surprised if the reflex doesn't happen. To get into the reflexogenic zone, you need to stretch the tendon. In all other cases, there will be no reflex.

Organism Levels: cellular, tissue, organ, system, organism.

Organ level form organs - independent anatomical formations that occupy a certain place in the body, have a certain structure and perform certain functions.

System level represented by groups (systems) of organs that perform common functions.

organism as a whole, uniting the work of all systems, constitutes the organismic level.

Behaviorallevel, which determines the adaptation of the organism to the natural, and in humans, to the social environment.

The nervous and endocrine regulatory systems unite all levels of the body, ensuring the coordinated work of all executive organs and their systems.

The blinking reflex is a bioelectric analogue of the corneal reflex. As you know, the afferent part of the reflex arc in this case are the fibers n. trigeminus, and efferent - n. facialis. This must be remembered, since in the classical concept, the blinking reflex itself is caused by illumination of the eye or the sudden appearance of an object in the field of view. Naturally, the sensory nerve providing this reflex is n. opticus. An irritant can also be a sudden touch, a loud sound.

The method below has found the greatest application in clinical practice.

When studying the “blinking” reflex, the discharge electrodes are placed above m. orbicularis oculi on both sides, and the stimulation electrode is in the projection of the exit point n. supraorbitalis (Fig. 8), performing two-channel registration. Stimulation is carried out by non-rhythmic pulses with an interval of 10-15 s and an intensity of 15 to 25 mA.

Rice. 8. Method of applying electrodes during registration of the “blinking” reflex.

The resulting response contains two main components: early (R1), arising on the side of stimulation as a result of a monosynaptic reflex, closing at the level of the brain stem, and late (R2), bilateral, since the upper part of the mimic muscles normally has bilateral cortical innervation (Fig. . 9). The figure shows the presence of the R1 and R2 components during ipsilateral stimulation and the R2 component during contralateral stimulation.

Fig.9. The "blink" reflex is normal. 1k,1 and 2k,1 - stimulation on the right, 1k,2 and 2k,2 - stimulation on the left.

Depending on the task of the study, they evaluate:

1) preservation of reflex components;

2) latent time of R1 and R2 components on the side of stimulation;

3) latent time of the R2 component on the opposite side;

4) symmetry of the reflex;

5) the presence of a reflex in the lower part of the facial muscles (in the case of pathological synkinesis).

The corneal reflex may be absent even with normal function of the trigeminal and facial nerves - most likely as a result of damage to the reflex collaterals. The absence of a reflex may be “functional” in nature (for example, in hysteria). Unilateral loss always has an organic basis.

For differential diagnosis of the level of damage, it is necessary to study the reflex on both sides (Fig. 10).

Rice. Fig. 10. Study of the “blink” reflex in a patient with peripheral paresis of the left facial nerve (same designations as in Fig. 9).

Analyzing the results of the study given as an example, it is necessary to pay attention to the signs of the loss of the function n. facialis sinistra, which is manifested by the absence of reflex components on the left both during ipsilateral and contralateral stimulation.

In another example, along with the defeat of n. facialis sinistra, a violation of the trigeminal nerve is found (Fig. 11). During stimulation on the right, both R1 and R2 components are detected ipsilaterally, and on the left, the late component is absent as a result of impaired conduction along the left facial nerve. When stimulated on the left, the R2 component on the right does not appear, indicating damage to the left trigeminal nerve.

Of course, without taking into account the data of the study of the neurological status, only a preliminary topical diagnosis is possible.

Rice. Fig. 11. Study of the “blink” reflex in a patient with paresis of the left facial nerve and impaired conduction along the trigeminal nerve on the left (the designations are the same as in Fig. 9).

A reflex is a response of the body to irritation, carried out by excitation of the central nervous system and having an adaptive value.

This definition contains 5 signs of a reflex:

1) it is a response, not a spontaneous one,

2) irritation is necessary, without which the reflex does not occur,

3) the reflex is based on nervous excitation,

4) the participation of the central nervous system is necessary to turn sensory excitation into effector,

5) a reflex is needed to adapt (adapt) to changing environmental conditions.

Reflexes are divided into 2 large groups: unconditional and conditional.

Blink reflex - a protective reaction of the body to light, sound, touching the cornea or eyelashes, tapping in the glabella and other irritants. It also occurs with electrical stimulation of the supraorbital nerve (a branch of the trigeminal), which is used as a neurophysiological test.

The blinking reflex was described in 1896 and is reduced to a contraction of the circular muscle of the eye during mechanical stimulation of the superior ophthalmic nerve.
The center of this protective reflex, like many protective reflexes (sneezing, coughing, vomiting, tearing), is located in the medulla oblongata of the brain.

When you touch the inner corner of the eye, a blinking reflex occurs, after several touches it is inhibited. Touching the inner corner of the eye causes irritation of the receptors. They are excited, and nerve impulses from the receptors are transmitted along the sensitive neuron to the CIS.

From the CIS, nerve impulses arrive at the executive neuron. A synapse is formed at the point of contact between the axon of the executive neuron and the muscle cell. Bubbles with excitatory biologically active substances burst, the liquid pours into the synaptic cleft and affects the cell wall of the muscle cell, which is excited and contracts. There is a blinking reflex. After several touches, the blinking reflex disappears.

Inhibition does not allow excitation to spread indefinitely. Receptors in muscle cells send signals to the nerve center. From the nerve center through the executive neuron, nerve impulses reach the synapse, the bubbles with inhibitory substances burst, the fluid pours into the synaptic cleft, and affects the cell membranes of muscle cells. The action of muscle cells is inhibited.

With the help of an effort of will, you can slow down the action of the blinking reflex. A nerve impulse arises in the nerve center. The nerve impulse reaches the synapse, in which bubbles with inhibitory biologically active substances burst. The fluid pours into the synaptic cleft and acts on the cell membranes of the muscle cells. There is inhibition of the blinking reflex.

When a mote enters the eye, the receptors of the membrane of the eye are irritated. They are excited, and nerve impulses from the receptors are transmitted along the sensitive neuron to the nerve center. From the nerve center, nerve impulses are sent to the executive neuron, which activates the circular muscles of the eye that close the eyelids. After removing the mote, the principle of "feedback" is triggered. A signal is sent to the nerve center. Information about the change in the situation is being processed. The nerve center sends nerve impulses that reach the synapse, the bubbles with inhibitory substances burst, the fluid pours into the synaptic cleft, and affects the cell membranes of muscle cells. The action of muscle cells stops. The blink reflex is inhibited.

The blinking reflex is a protective reaction of the body, which is carried out and controlled by the nervous system.

With a tension headache, an increase in reflex excitability occurs: reflexes begin to be caused by weaker stimuli (decrease in the threshold of sensitivity), at the same time, the response becomes more powerful and lasts longer. The pathogenesis (causes) of tension headache is associated with these phenomena, which are clearly visible when the blinking reflex is evoked: a pain reaction begins to occur as a result of exposure to even an inadequately weak stimulus.

The specificity of the vision of a newborn is the blinking reflex. Its essence lies in the fact that no matter how much you swing objects near the eyes, the baby does not blink, but he reacts to a bright and sudden beam of light. This is explained by the fact that at birth the child's visual analyzer is still at the very beginning of its development. The vision of the newborn is assessed at the level of sensation of light. That is, the baby is able to perceive only the light itself without perceiving the structure of the image.