Organs innervated by the sympathetic nervous system. Sympathetic division of the autonomic nervous system
The sympathetic system mobilizes the body’s forces in emergency situations, increases the waste of energy resources; parasympathetic - promotes restoration and accumulation of energy resources.
The activity of the sympathetic nervous system and the secretion of adrenaline by the adrenal medulla are related to each other, but do not always change to the same extent. Thus, with particularly strong stimulation of the sympathoadrenal system (for example, during general cooling or intense physical activity), the secretion of adrenaline increases, enhancing the action of the sympathetic nervous system. In other situations, sympathetic activity and adrenaline secretion may be independent. In particular, the orthostatic response primarily involves the sympathetic nervous system, while the response to hypoglycemia primarily involves the adrenal medulla.
Most preganglionic sympathetic neurons have thin myelinated axons - B fibers. However, some axons are unmyelinated C-fibers. The conduction velocity along these axons ranges from 1 to 20 m/s. They leave the spinal cord as part of the ventral roots and white communicating rami and end in paired paravertebral ganglia or unpaired prevertebral ganglia. Through nerve branches, the paraventebral ganglia are connected into sympathetic trunks running on both sides of the spine from the base of the skull to the sacrum. Thinner unmyelinated postganglionic axons depart from the sympathetic trunks, which either go to peripheral organs as part of the gray connecting branches, or form special nerves going to the organs of the head, chest, abdominal and pelvic cavities. Postganglionic fibers from the prevertebral ganglia (celiac, superior and inferior mesenteric) go through the plexuses or as part of special nerves to the abdominal organs and pelvic organs.
Preganglionic axons leave the spinal cord as part of the anterior root and enter the paravertebral ganglion at the level of the same segment through the white communicating branches. White connecting branches are present only at levels Th1-L2. Preganglionic axons end at synapses in this ganglion or, after passing through it, enter the sympathetic trunk (sympathetic chain) of the paravertebral ganglia or the splanchnic nerve (Fig. 41.2).
As part of the sympathetic chain, preganglionic axons are directed rostrally or caudally to the nearest or distant paravertebral ganglion and form synapses there. Having left it, the axons go to the spinal nerve, usually through the gray communicating branch, which is present in each of the 31 pairs of spinal nerves. As part of the peripheral nerves, postganglionic axons enter the effectors of the skin (piloerector muscles, blood vessels, sweat glands), muscles, and joints. Typically, postganglionic axons are unmyelinated (C fibers), although there are exceptions. The differences between the white and gray connecting branches depend on their relative content of myelinated and unmyelinated axons.
As part of the splanchnic nerve, preganglionic axons often go to the prevertebral ganglion, where they form synapses, or they can pass through the ganglion, ending in a more distal ganglion. Some of them, running as part of the splanchnic nerve, end directly on the cells of the adrenal medulla.
The sympathetic chain stretches from the cervical to the coccygeal level of the spinal cord. It acts as a distribution system, allowing preganglionic neurons, which are located only in the thoracic and upper lumbar segments, to activate postganglionic neurons, which supply all segments of the body. However, there are fewer paravertebral ganglia than spinal segments, since some ganglia fuse during ontogeny. For example, the superior cervical sympathetic ganglion is composed of fused C1-C4 ganglia, the middle cervical sympathetic ganglion is composed of C5-C6, and the inferior cervical sympathetic ganglion is composed of C7-C8. The stellate ganglion is formed by the fusion of the inferior cervical sympathetic ganglion with the Th1 ganglion. The superior cervical ganglion provides postganglionic innervation to the head and neck, and the middle cervical and stellate - the heart, lungs and bronchi.
Typically, the axons of preganglionic sympathetic neurons distribute to the ipsilateral ganglia and therefore regulate autonomic functions on the same side of the body. An important exception is the bilateral sympathetic innervation of the intestines and pelvic organs. Like the motor nerves of skeletal muscles, the axons of preganglionic sympathetic neurons belonging to specific organs innervate several segments. Thus, preganglionic sympathetic neurons that provide sympathetic functions to the head and neck areas are located in the C8-Th5 segments, and those belonging to the adrenal glands are in Th4-Th12.
Consists of central and peripheral sections.
Central department– form cells of the lateral horns of the spinal cord (gray matter) at the level from the 8th cervical to the 2nd lumbar segments of the spinal cord.
Peripheral department- represented by prenodular nerve fibers, which run as part of the anterior roots of the spinal cord and are interrupted in the nodes of the sympathetic trunk. Nerve nodes are divided into 2 groups:
1. Paravertebrates(paravertebral), located in two chains on the sides of the spine and forming right and left sympathetic trunks.
2. Prevertebrates(prevertebral) are nodes of the peripheral nerve plexuses lying in the chest and abdominal cavities.
Sympathetic nerve fibers leave the spinal cord as part of the anterior roots of the spinal nerves, and then through the connecting branch are sent to the corresponding node of the sympathetic trunk. There, some of the fibers switch to the postganglionic neuron, and its fibers go to the organs. The other part follows through the node without interruption and approaches the prevertebral nodes, switches to them, and then the postganglionic fibers follow to the organs.
Postganglionic sympathetic fibers are characterized by the formation of plexuses along the arteries supplying this organ.
In addition, they can form independently running nerves (for example, the splanchnic nerve) and be part of the peripheral branches of the SMN and CN.
Sympathetic trunks ( right and left) are chains of nerve ganglia connected by internodal branches, located on both sides along the spine (consists of 20–25 nerve ganglia).
In the thoracic and upper lumbar region, each node is connected white connecting branch with the corresponding spinal nerve. Through these branches, preganglionic fibers coming from the brain in the anterior roots pass into the node of the sympathetic trunk. Since they are composed of pulpy fibers, these tufts are white in color.
From all nodes sympathetic trunk to the SMN go gray connecting branches, consisting of postganglionic gray fibers.
The sympathetic trunk is divided into cervical, thoracic, lumbar, sacral (and coccygeal) sections.
Cervical region- located at the level of the base of the skull before the entrance to the chest cavity. It is represented by 3 nodes: upper, middle and lower, lying in front of the deep muscles of the neck. The largest of them is the upper node; branches extend from it, due to which the organs of the head and neck (skin, blood vessels) are innervated. These branches form plexuses on the internal and external carotid arteries and along their branches reach the lacrimal gland, salivary glands, glands of the mucous membrane of the pharynx, larynx, tongue, and the dilator muscle.
The lower cervical node often merges with the first thoracic node, forming star knot– gives off branches for innervation of the thyroid gland, vessels of the brain and spinal cord, mediastinal organs, forms deep and superficial cardiac and other plexuses and provides sympathetic innervation of the heart.
From all three cervical nodes of both sympathetic trunks arise cardiac nerves, which descend into the chest cavity and there, together with the branches of the vagus nerves on the ascending aorta and pulmonary trunk, form superficial and deep cardiac nerve plexuses, from which nerves go to the wall of the heart.
Thoracic region- consists of 10-12 nodes lying in front of the heads of the ribs and covered by the pleura. From the nodes of the thoracic region branches extend to the aorta, heart, lungs, bronchi, esophagus, forming organ plexuses. The largest nerves coming from the 5-9 and 10-11 thoracic ganglia are the major and minor splanchnic nerves. Both of them pass between the legs of the diaphragm into the abdominal cavity, where they approach the nodes of the celiac plexus. They carry preganglionic fibers to the cells of the celiac ganglia.
Lumbar– consists of 2-7 nodes located on the anterolateral surfaces of the lumbar vertebral bodies. From them come the branches involved in the formation of the autonomic nerve plexuses of the abdominal cavity and pelvis.
Sacral section- consists of four nodes located on the anterior surface of the sacrum.
Below, the chains of nodes of the right and left sympathetic trunks are connected in one coccygeal unpaired node. All these formations are united under the name of the pelvic section of the sympathetic trunk.
From them come branches involved in the formation of the vegetative plexuses of the pelvis, which innervate the glands, vessels, and organs of the pelvic region (genitourinary organs of the small pelvis, external genitalia, final sections of the intestine).
Topographically, the following main plexuses are distinguished in the abdominal cavity: celiac, superior and inferior mesenteric, abdominal, aortic, intercostal, superior and inferior hypogastric plexuses, hypogastric nerves, etc.
Celiac plexus– located at the level of the 12th thoracic vertebra, in the shape of a horseshoe, this is the largest plexus. Consists of several large nodes. This plexus is approached by the right and left large and small splanchnic nerves from the thoracic nodes and the lumbar splanchnic nerves from the lumbar nodes of the sympathetic trunk. The fibers of the vagus and sensory fibers of the right phrenic nerve also join.
Nerve branches depart from the celiac nodes, forming plexuses of the same name around the celiac trunk and its branches, which, together with the arteries, go to the corresponding organs and innervate them (hepatic, splenic, gastric, pancreatic, adrenal and diaphragmatic).
4. Parasympathetic nervous system has a central (head) and peripheral sections (sacral).
Central department– represented by parasympathetic nuclei lying in the midbrain, hindbrain, medulla oblongata and in the sacral segments of the spinal cord (III,VII, IX, X).
Peripheral part- consists of nodes and fibers that are part of the III, VII, IX and X pairs of the cranial nerves and pelvic nerves.
In the midbrain, next to the motor nucleus of the 3rd pair of nerves, lies the parasympathetic additional nucleus (Yakubovich nucleus), the cell processes of which are part of the oculomotor nerve (3 pairs), switch in the ciliary ganglion, which lies in the orbit and innervates the eye muscle.
In the rhomboid fossa next to the nucleus of the facial nerve lies superior salivary nucleus. The processes of its cells are part of the intermediate nerve, then into the facial nerve. As part of the branches of the facial and trigeminal nerves, parasympathetic fibers reach the lacrimal gland, glands of the mucous membrane of the nasal and oral cavities, switching in the pterygopalatine ganglion, where the preganglionic parasympathetic fibers end. The second part of the preganglionic parasympathetic fibers of the intermediate nerve, as part of the chorda tympani, reaches the lingual nerve and, together with it, goes to the mandibular salivary gland for its secretory innervation.
There are parasympathetic fibers of the glossopharyngeal nerve and parasympathetic fibers of the vagus nerve.
Sacral section is formed by the sacral parasympathetic nuclei, which lie in the intermediolateral nucleus of the lateral horn of the gray matter of the spinal cord at the level of 2-4 sacral segments.
There are rectal, prostatic, uterovaginal, vesical and other plexuses that contain parasympathetic pelvic nodes, on their cells the preganglionic fibers of the pelvic splanchnic nerves end; these fibers are sent to the organs and innervate smooth muscles and glands.
Under The term sympathetic nervous system refers to specific segment (department) autonomic nervous system. Its structure is characterized by some segmentation. This section is classified as trophic. Its tasks are to supply the organs with nutrients,, if necessary, increase the rate of oxidative processes, improve breathing, and create conditions for the supply of more oxygen to the muscles. In addition, an important task is to speed up the work of the heart if necessary.
Lecture for doctors "Sympathetic nervous system". The autonomic nervous system is divided into sympathetic and parasympathetic parts. The sympathetic part of the nervous system includes:
- lateral intermediate substance in the lateral columns of the spinal cord;
- sympathetic nerve fibers and nerves going from the cells of the lateral intermediate substance to the nodes of the sympathetic and autonomic plexuses of the abdominal pelvic cavity;
- sympathetic trunk, communicating nerves connecting the spinal nerves to the sympathetic trunk;
- nodes of the autonomic nerve plexuses;
- nerves running from these plexuses to the organs;
- sympathetic fibers.
AUTONOMIC NERVOUS SYSTEM
The autonomic (autonomic) nervous system regulates all internal processes of the body: the functions of internal organs and systems, glands, blood and lymph vessels, smooth and partially striated muscles, sensory organs (Fig. 6.1). It ensures homeostasis of the body, i.e. the relative dynamic constancy of the internal environment and the stability of its basic physiological functions (blood circulation, respiration, digestion, thermoregulation, metabolism, excretion, reproduction, etc.). In addition, the autonomic nervous system performs an adaptation-trophic function - regulation of metabolism in relation to environmental conditions.
The term "autonomic nervous system" reflects the control of involuntary functions of the body. The autonomic nervous system is dependent on the higher centers of the nervous system. There is a close anatomical and functional relationship between the autonomic and somatic parts of the nervous system. Autonomic nerve conductors pass through the cranial and spinal nerves. The main morphological unit of the autonomic nervous system, like the somatic one, is the neuron, and the main functional unit is the reflex arc. The autonomic nervous system has a central (cells and fibers located in the brain and spinal cord) and peripheral (all its other formations) sections. There are also sympathetic and parasympathetic parts. Their main difference lies in the characteristics of functional innervation and is determined by their attitude to drugs that affect the autonomic nervous system. The sympathetic part is excited by adrenaline, and the parasympathetic part by acetylcholine. Ergotamine has an inhibitory effect on the sympathetic part, and atropine has an inhibitory effect on the parasympathetic part.
6.1. Sympathetic division of the autonomic nervous system
The central formations are located in the cerebral cortex, hypothalamic nuclei, brain stem, reticular formation, and also in the spinal cord (in the lateral horns). The cortical representation has not been sufficiently elucidated. From the cells of the lateral horns of the spinal cord at levels from C VIII to L V, the peripheral formations of the sympathetic department begin. The axons of these cells pass as part of the anterior roots and, having separated from them, form a connecting branch that approaches the nodes of the sympathetic trunk. This is where some of the fibers end. From the cells of the nodes of the sympathetic trunk, the axons of the second neurons begin, which again approach the spinal nerves and end in the corresponding segments. The fibers that pass through the nodes of the sympathetic trunk, without interruption, approach the intermediate nodes located between the innervated organ and the spinal cord. From the intermediate nodes, the axons of the second neurons begin, heading to the innervated organs.
Rice. 6.1.
1 - cortex of the frontal lobe of the cerebrum; 2 - hypothalamus; 3 - ciliary node; 4 - pterygopalatine node; 5 - submandibular and sublingual nodes; 6 - ear node; 7 - superior cervical sympathetic node; 8 - great splanchnic nerve; 9 - internal node; 10 - celiac plexus; 11 - celiac nodes; 12 - small splanchnic nerve; 12a - lower splanchnic nerve; 13 - superior mesenteric plexus; 14 - inferior mesenteric plexus; 15 - aortic plexus; 16 - sympathetic fibers to the anterior branches of the lumbar and sacral nerves for the vessels of the legs; 17 - pelvic nerve; 18 - hypogastric plexus; 19 - ciliary muscle; 20 - sphincter of the pupil; 21 - pupil dilator; 22 - lacrimal gland; 23 - glands of the mucous membrane of the nasal cavity; 24 - submandibular gland; 25 - sublingual gland; 26 - parotid gland; 27 - heart; 28 - thyroid gland; 29 - larynx; 30 - muscles of the trachea and bronchi; 31 - lung; 32 - stomach; 33 - liver; 34 - pancreas; 35 - adrenal gland; 36 - spleen; 37 - kidney; 38 - large intestine; 39 - small intestine; 40 - detrusor of the bladder (muscle that pushes urine); 41 - sphincter of the bladder; 42 - gonads; 43 - genitals; III, XIII, IX, X - cranial nerves
The sympathetic trunk is located along the lateral surface of the spine and includes 24 pairs of sympathetic nodes: 3 cervical, 12 thoracic, 5 lumbar, 4 sacral. From the axons of the cells of the upper cervical sympathetic node, the sympathetic plexus of the carotid artery is formed, from the lower - the upper cardiac nerve, which forms the sympathetic plexus in the heart. The thoracic nodes innervate the aorta, lungs, bronchi, and abdominal organs, and the lumbar nodes innervate the pelvic organs.
6.2. Parasympathetic division of the autonomic nervous system
Its formations begin from the cerebral cortex, although the cortical representation, as well as the sympathetic part, has not been sufficiently elucidated (mainly the limbic-reticular complex). There are mesencephalic and bulbar sections in the brain and sacral sections in the spinal cord. The mesencephalic section includes the nuclei of the cranial nerves: III pair - accessory nucleus of Yakubovich (paired, parvocellular), innervating the muscle that constricts the pupil; Perlia's nucleus (unpaired parvocellular) innervates the ciliary muscle involved in accommodation. The bulbar section consists of the superior and inferior salivary nuclei (VII and IX pairs); X pair - vegetative nucleus, innervating the heart, bronchi, gastrointestinal tract,
its digestive glands and other internal organs. The sacral section is represented by cells in segments S II -S IV, the axons of which form the pelvic nerve, innervating the genitourinary organs and rectum (Fig. 6.1).
All organs are under the influence of both the sympathetic and parasympathetic parts of the autonomic nervous system, with the exception of blood vessels, sweat glands and the adrenal medulla, which have only sympathetic innervation. The parasympathetic department is more ancient. As a result of its activity, stable states of organs and conditions for the creation of reserves of energy substrates are created. The sympathetic part modifies these states (i.e., the functional abilities of the organs) in relation to the function performed. Both parts function in close cooperation. Under certain conditions, functional predominance of one part over the other is possible. If the tone of the parasympathetic part predominates, a state of parasympathotonia develops, and the sympathetic part - sympathotonia. Parasympathotonia is characteristic of the sleep state, sympathotonia is characteristic of affective states (fear, anger, etc.).
In clinical conditions, conditions are possible in which the activity of individual organs or systems of the body is disrupted as a result of the predominance of the tone of one of the parts of the autonomic nervous system. Parasympathotonic manifestations accompany bronchial asthma, urticaria, Quincke's edema, vasomotor rhinitis, motion sickness; sympathotonic - vascular spasm in the form of Raynaud's syndrome, migraine, transient form of hypertension, vascular crises with hypothalamic syndrome, ganglion lesions, panic attacks. The integration of autonomic and somatic functions is carried out by the cerebral cortex, hypothalamus and reticular formation.
6.3. Limbic-reticular complex
All activities of the autonomic nervous system are controlled and regulated by the cortical parts of the nervous system (frontal cortex, parahippocampal and cingulate gyri). The limbic system is the center of emotion regulation and the neural substrate of long-term memory. The rhythm of sleep and wakefulness is also regulated by the limbic system.
The limbic system (Fig. 6.2) is understood as a number of closely interconnected cortical and subcortical structures that have common development and functions. It also includes the formations of the olfactory pathways located at the base of the brain, the septum pellucidum, the vaulted gyrus, the cortex of the posterior orbital surface of the frontal lobe, the hippocampus, and the dentate gyrus. The subcortical structures of the limbic system include the caudate nucleus, putamen, amygdala, anterior tubercle of the thalamus, hypothalamus, frenulus nucleus. The limbic system includes a complex interweaving of ascending and descending pathways, closely associated with the reticular formation.
Irritation of the limbic system leads to the mobilization of both sympathetic and parasympathetic mechanisms, which has corresponding autonomic manifestations. A pronounced autonomic effect occurs when the anterior parts of the limbic system are irritated, in particular the orbital cortex, amygdala and cingulate gyrus. In this case, changes in salivation, respiratory rate, increased intestinal motility, urination, defecation, etc. appear.
Of particular importance in the functioning of the autonomic nervous system is the hypothalamus, which regulates the functions of the sympathetic and parasympathetic systems. In addition, the hypothalamus realizes the interaction of nervous and endocrine, the integration of somatic and autonomic activity. The hypothalamus has specific and nonspecific nuclei. Specific nuclei produce hormones (vasopressin, oxytocin) and releasing factors that regulate the secretion of hormones by the anterior pituitary gland.
Sympathetic fibers innervating the face, head and neck begin from cells located in the lateral horns of the spinal cord (C VIII -Th III). Most of the fibers are interrupted in the superior cervical sympathetic ganglion, and a smaller part is directed to the external and internal carotid arteries and forms periarterial sympathetic plexuses on them. They are joined by postganglionic fibers coming from the middle and lower cervical sympathetic nodes. In small nodules (cellular accumulations) located in the periarterial plexuses of the branches of the external carotid artery, fibers that are not interrupted in the nodes of the sympathetic trunk end. The remaining fibers are interrupted in the facial ganglia: ciliary, pterygopalatine, sublingual, submandibular and auricular. Postganglionic fibers from these nodes, as well as fibers from the cells of the superior and other cervical sympathetic nodes, go to the tissues of the face and head, partly as part of the cranial nerves (Fig. 6.3).
Afferent sympathetic fibers from the head and neck are directed to the periarterial plexuses of the branches of the common carotid artery, pass through the cervical nodes of the sympathetic trunk, partially contacting their cells, and through the connecting branches they approach the spinal nodes, closing the reflex arc.
Parasympathetic fibers are formed by the axons of the stem parasympathetic nuclei and are directed mainly to the five autonomic ganglia of the face, where they are interrupted. A minority of the fibers are directed to the parasympathetic clusters of cells of the periarterial plexuses, where they are also interrupted, and the postganglionic fibers go as part of the cranial nerves or periarterial plexuses. The parasympathetic part also contains afferent fibers that run in the vagus nerve system and are directed to the sensory nuclei of the brain stem. The anterior and middle sections of the hypothalamic region, through sympathetic and parasympathetic conductors, influence the function of predominantly ipsilateral salivary glands.
6.5. Autonomic innervation of the eye
Sympathetic innervation. Sympathetic neurons are located in the lateral horns of segments C VIII - Th III of the spinal cord (centrun ciliospinale).
Rice. 6.3.
1 - posterior central nucleus of the oculomotor nerve; 2 - accessory nucleus of the oculomotor nerve (Yakubovich-Edinger-Westphal nucleus); 3 - oculomotor nerve; 4 - nasociliary branch from the optic nerve; 5 - ciliary node; 6 - short ciliary nerves; 7 - sphincter of the pupil; 8 - pupil dilator; 9 - ciliary muscle; 10 - internal carotid artery; 11 - carotid plexus; 12 - deep petrosal nerve; 13 - upper salivary nucleus; 14 - intermediate nerve; 15 - elbow assembly; 16 - greater petrosal nerve; 17 - pterygopalatine node; 18 - maxillary nerve (II branch of the trigeminal nerve); 19 - zygomatic nerve; 20 - lacrimal gland; 21 - mucous membranes of the nose and palate; 22 - genicular tympanic nerve; 23 - auriculotemporal nerve; 24 - middle meningeal artery; 25 - parotid gland; 26 - ear node; 27 - lesser petrosal nerve; 28 - tympanic plexus; 29 - auditory tube; 30 - single track; 31 - lower salivary nucleus; 32 - drum string; 33 - tympanic nerve; 34 - lingual nerve (from the mandibular nerve - III branch of the trigeminal nerve); 35 - taste fibers to the anterior 2/3 of the tongue; 36 - sublingual gland; 37 - submandibular gland; 38 - submandibular node; 39 - facial artery; 40 - superior cervical sympathetic node; 41 - cells of the lateral horn ThI-ThII; 42 - lower node of the glossopharyngeal nerve; 43 - sympathetic fibers to the plexuses of the internal carotid and middle meningeal arteries; 44 - innervation of the face and scalp. III, VII, IX - cranial nerves. Parasympathetic fibers are indicated in green, sympathetic in red, and sensory in blue.
The processes of these neurons, forming preganglionic fibers, leave the spinal cord along with the anterior roots, enter the sympathetic trunk as part of the white connecting branches and, without interruption, pass through the overlying nodes, ending at the cells of the upper cervical sympathetic plexus. Postganglionic fibers of this node accompany the internal carotid artery, weaving around its wall, penetrate into the cranial cavity, where they connect with the first branch of the trigeminal nerve, penetrate into the orbital cavity and end at the muscle that dilates the pupil (m. dilatator pupillae).
Sympathetic fibers also innervate other structures of the eye: the tarsal muscles that expand the palpebral fissure, the orbital muscle of the eye, as well as some structures of the face - the sweat glands of the face, smooth muscles of the face and blood vessels.
Parasympathetic innervation. The preganglionic parasympathetic neuron lies in the accessory nucleus of the oculomotor nerve. As part of the latter, it leaves the brain stem and reaches the ciliary ganglion (ganglion ciliare), where it switches to postganglionic cells. From there, part of the fibers is sent to the muscle that constricts the pupil (m. sphincter pupillae), and the other part is involved in providing accommodation.
Disturbance of the autonomic innervation of the eye. Damage to the sympathetic formations causes Bernard-Horner syndrome (Fig. 6.4) with constriction of the pupil (miosis), narrowing of the palpebral fissure (ptosis), and retraction of the eyeball (enophthalmos). The development of homolateral anhidrosis, conjunctival hyperemia, and depigmentation of the iris are also possible.
The development of Bernard-Horner syndrome is possible when the lesion is localized at different levels - involving the posterior longitudinal fasciculus, pathways to the muscle that dilates the pupil. The congenital variant of the syndrome is more often associated with birth trauma with damage to the brachial plexus.
When sympathetic fibers are irritated, a syndrome occurs that is the opposite of Bernard-Horner syndrome (Pourfour du Petit) - dilatation of the palpebral fissure and pupil (mydriasis), exophthalmos.
6.6. Autonomic innervation of the bladder
Regulation of bladder activity is carried out by the sympathetic and parasympathetic parts of the autonomic nervous system (Fig. 6.5) and includes urinary retention and bladder emptying. Normally, retention mechanisms are more activated, which
Rice. 6.4. Right-sided Bernard-Horner syndrome. Ptosis, miosis, enophthalmos
is carried out as a result of activation of sympathetic innervation and blockade of the parasympathetic signal at the level of segments L I - L II of the spinal cord, while the activity of the detrusor is suppressed and the tone of the muscles of the internal sphincter of the bladder increases.
Regulation of the act of urination occurs when activated
the parasympathetic center at the level of S II -S IV and the micturition center in the pons (Fig. 6.6). Descending efferent signals send signals that relax the external sphincter, suppress sympathetic activity, remove the block of conduction along parasympathetic fibers, and stimulate the parasympathetic center. The consequence of this is contraction of the detrusor and relaxation of the sphincters. This mechanism is under the control of the cerebral cortex; the reticular formation, the limbic system, and the frontal lobes of the cerebral hemispheres take part in the regulation.
Voluntary cessation of urination occurs when a command is received from the cerebral cortex to the micturition centers in the brain stem and sacral spinal cord, which leads to contraction of the external and internal sphincters of the pelvic floor muscles and periurethral striated muscles.
Damage to the parasympathetic centers of the sacral region and the autonomic nerves emanating from it is accompanied by the development of urinary retention. It can also occur when the spinal cord is damaged (trauma, tumor, etc.) at a level above the sympathetic centers (Th XI -L II). Partial damage to the spinal cord above the level of the autonomic centers can lead to the development of an imperative urge to urinate. When the spinal sympathetic center (Th XI - L II) is damaged, true urinary incontinence occurs.
Research methodology. There are numerous clinical and laboratory methods for studying the autonomic nervous system; their choice is determined by the task and conditions of the study. However, in all cases it is necessary to take into account the initial autonomic tone and the level of fluctuations relative to the background value. The higher the initial level, the lower the response will be during functional tests. In some cases, even a paradoxical reaction is possible. Ray study
Rice. 6.5.
1 - cerebral cortex; 2 - fibers that provide voluntary control over bladder emptying; 3 - fibers of pain and temperature sensitivity; 4 - cross section of the spinal cord (Th IX -L II for sensory fibers, Th XI -L II for motor fibers); 5 - sympathetic chain (Th XI -L II); 6 - sympathetic chain (Th IX -L II); 7 - cross section of the spinal cord (segments S II -S IV); 8 - sacral (unpaired) node; 9 - genital plexus; 10 - pelvic splanchnic nerves;
11 - hypogastric nerve; 12 - lower hypogastric plexus; 13 - genital nerve; 14 - external sphincter of the bladder; 15 - bladder detrusor; 16 - internal sphincter of the bladder
Rice. 6.6.
It is better to do it in the morning on an empty stomach or 2 hours after meals, at the same time, at least 3 times. The minimum value of the received data is taken as the initial value.
The main clinical manifestations of the predominance of the sympathetic and parasympathetic systems are presented in table. 6.1.
To assess autonomic tone, it is possible to conduct tests with exposure to pharmacological agents or physical factors. Solutions of adrenaline, insulin, mezaton, pilocarpine, atropine, histamine, etc. are used as pharmacological agents.
Cold test. With the patient lying down, heart rate is calculated and blood pressure is measured. After this, the hand of the other hand is immersed in cold water (4 °C) for 1 minute, then the hand is removed from the water and blood pressure and pulse are recorded every minute until it returns to the original level. Normally this happens within 2-3 minutes. When blood pressure increases by more than 20 mm Hg. Art. the reaction is considered pronounced sympathetic, less than 10 mm Hg. Art. - moderate sympathetic, and with a decrease in blood pressure - parasympathetic.
Oculocardiac reflex (Danyini-Aschner). When pressing on the eyeballs in healthy people, the heart rate slows down by 6-12 per minute. If the heart rate decreases by 12-16 per minute, this is regarded as a sharp increase in the tone of the parasympathetic part. The absence of a decrease or an increase in heart rate by 2-4 per minute indicates an increase in the excitability of the sympathetic department.
Solar reflex. The patient lies on his back, and the examiner presses his hand on the upper abdomen until a pulsation of the abdominal aorta is felt. After 20-30 s, the heart rate slows down in healthy people by 4-12 per minute. Changes in cardiac activity are assessed in the same way as when inducing the oculocardiac reflex.
Orthoclinostatic reflex. The patient's heart rate is calculated while lying on his back, and then he is asked to quickly stand up (orthostatic test). When moving from a horizontal to a vertical position, heart rate increases by 12 per minute with an increase in blood pressure by 20 mmHg. Art. When the patient moves to a horizontal position, pulse and blood pressure return to their original values within 3 minutes (clinostatic test). The degree of pulse acceleration during an orthostatic test is an indicator of the excitability of the sympathetic division of the autonomic nervous system. A significant slowdown of the pulse during a clinostatic test indicates an increase in the excitability of the parasympathetic department.
Table 6.1.
Adrenaline test. In a healthy person, subcutaneous injection of 1 ml of 0.1% adrenaline solution after 10 minutes causes pale skin, increased blood pressure, increased heart rate and increased blood glucose levels. If such changes occur faster and are more pronounced, then the tone of the sympathetic innervation is increased.
Skin test with adrenaline. A drop of 0.1% adrenaline solution is applied to the site of the skin injection with a needle. In a healthy person, such an area becomes pale with a pink halo around it.
Atropine test. Subcutaneous injection of 1 ml of 0.1% atropine solution in a healthy person causes dry mouth, decreased sweating, increased heart rate and dilated pupils. With an increase in the tone of the parasympathetic part, all reactions to the administration of atropine are weakened, so the test can be one of the indicators of the state of the parasympathetic part.
To assess the state of functions of segmental vegetative formations, the following tests can be used.
Dermographism. Mechanical irritation is applied to the skin (with the handle of a hammer, the blunt end of a pin). The local reaction occurs as an axon reflex. A red stripe appears at the site of irritation, the width of which depends on the state of the autonomic nervous system. With an increase in sympathetic tone, the stripe is white (white dermographism). Wide stripes of red dermographism, a stripe raised above the skin (elevated dermographism), indicate increased tone of the parasympathetic nervous system.
For topical diagnostics, reflex dermographism is used, which is caused by irritation with a sharp object (drawn across the skin with the tip of a needle). A strip with uneven scalloped edges appears. Reflex dermographism is a spinal reflex. It disappears in the corresponding zones of innervation when the dorsal roots, segments of the spinal cord, anterior roots and spinal nerves are affected at the level of the lesion, but remains above and below the affected area.
Pupillary reflexes. They determine the direct and friendly reaction of the pupils to light, the reaction to convergence, accommodation and pain (dilation of the pupils when pricking, pinching and other irritations of any part of the body).
Pilomotor reflex caused by pinching or applying a cold object (a test tube with cold water) or a cooling liquid (cotton wool soaked in ether) to the skin of the shoulder girdle or the back of the head. On the same half of the chest, “goose bumps” appear as a result of contraction of smooth hair muscles. The reflex arc closes in the lateral horns of the spinal cord, passes through the anterior roots and the sympathetic trunk.
Test with acetylsalicylic acid. After taking 1 g of acetylsalicylic acid, diffuse sweating appears. If the hypothalamic region is affected, its asymmetry is possible. When the lateral horns or anterior roots of the spinal cord are damaged, sweating is disrupted in the area of innervation of the affected segments. When the diameter of the spinal cord is damaged, taking acetylsalicylic acid causes sweating only above the site of the lesion.
Test with pilocarpine. The patient is injected subcutaneously with 1 ml of a 1% solution of pilocarpine hydrochloride. As a result of irritation of postganglionic fibers going to the sweat glands, sweating increases.
It should be borne in mind that pilocarpine excites peripheral M-cholinergic receptors, causing increased secretion of the digestive and bronchial glands, constriction of the pupils, increased tone of the smooth muscles of the bronchi, intestines, gall and bladder, and uterus, but pilocarpine has the most powerful effect on sweating. If the lateral horns of the spinal cord or its anterior roots are damaged in the corresponding area of the skin, sweating does not occur after taking acetylsalicylic acid, and the administration of pilocarpine causes sweating, since the postganglionic fibers that react to this drug remain intact.
Light bath. Warming the patient causes sweating. This is a spinal reflex, similar to the pilomotor reflex. Damage to the sympathetic trunk completely eliminates sweating after the use of pilocarpine, acetylsalicylic acid and body warming.
Skin thermometry. Skin temperature is examined using electrothermometers. Skin temperature reflects the state of blood supply to the skin, which is an important indicator of autonomic innervation. Areas of hyper-, normo- and hypothermia are determined. A difference in skin temperature of 0.5 °C in symmetrical areas indicates disturbances in autonomic innervation.
Electroencephalography is used to study the autonomic nervous system. The method allows us to judge the functional state of the synchronizing and desynchronizing systems of the brain during the transition from wakefulness to sleep.
There is a close connection between the autonomic nervous system and the emotional state of a person, therefore the psychological status of the subject is studied. For this purpose, special sets of psychological tests and the method of experimental psychological testing are used.
6.7. Clinical manifestations of lesions of the autonomic nervous system
When the autonomic nervous system is dysfunctional, a variety of disorders occur. Violations of its regulatory functions are periodic and paroxysmal. Most pathological processes do not lead to the loss of certain functions, but to irritation, i.e. to increased excitability of central and peripheral structures. On the-
disruption in some parts of the autonomic nervous system can spread to others (repercussion). The nature and severity of symptoms are largely determined by the level of damage to the autonomic nervous system.
Damage to the cerebral cortex, especially the limbic-reticular complex, can lead to the development of autonomic, trophic, and emotional disorders. They can be caused by infectious diseases, injuries to the nervous system, and intoxications. Patients become irritable, hot-tempered, quickly exhausted, they experience hyperhidrosis, instability of vascular reactions, fluctuations in blood pressure and pulse. Irritation of the limbic system leads to the development of paroxysms of severe vegetative-visceral disorders (cardiac, gastrointestinal, etc.). Psychovegetative disorders are observed, including emotional disorders (anxiety, restlessness, depression, asthenia) and generalized autonomic reactions.
If the hypothalamic region is damaged (Fig. 6.7) (tumor, inflammatory processes, circulatory disorders, intoxication, trauma), vegetative-trophic disorders may occur: disturbances in the rhythm of sleep and wakefulness, thermoregulation disorder (hyper- and hypothermia), ulcerations in the gastric mucosa, lower part of the esophagus, acute perforations of the esophagus, duodenum and stomach, as well as endocrine disorders: diabetes insipidus, adiposogenital obesity, impotence.
Damage to the autonomic formations of the spinal cord with segmental disorders and disorders localized below the level of the pathological process
Patients may exhibit vasomotor disorders (hypotension), disorders of sweating and pelvic functions. With segmental disorders, trophic changes are observed in the corresponding areas: increased dry skin, local hypertrichosis or local hair loss, trophic ulcers and osteoarthropathy.
When the nodes of the sympathetic trunk are affected, similar clinical manifestations occur, especially pronounced when the cervical nodes are involved. There is impaired sweating and disorder of pilomotor reactions, hyperemia and increased temperature of the skin of the face and neck; due to decreased tone of the laryngeal muscles, hoarseness and even complete aphonia may occur; Bernard-Horner syndrome.
Rice. 6.7.
1 - damage to the lateral zone (increased drowsiness, chills, increased pilomotor reflexes, constriction of the pupils, hypothermia, low blood pressure); 2 - damage to the central zone (impaired thermoregulation, hyperthermia); 3 - damage to the supraoptic nucleus (impaired secretion of antidiuretic hormone, diabetes insipidus); 4 - damage to the central nuclei (pulmonary edema and gastric erosion); 5 - damage to the paraventricular nucleus (adipsia); 6 - damage to the anteromedial zone (increased appetite and behavioral disturbances)
Damage to the peripheral parts of the autonomic nervous system is accompanied by a number of characteristic symptoms. The most common type of pain syndrome that occurs is sympathalgia. The pain is burning, pressing, bursting, and tends to gradually spread beyond the area of primary localization. Pain is provoked and intensified by changes in barometric pressure and ambient temperature. Changes in skin color are possible due to spasm or dilation of peripheral vessels: paleness, redness or cyanosis, changes in sweating and skin temperature.
Autonomic disorders can occur with damage to the cranial nerves (especially the trigeminal), as well as the median, sciatic, etc. Damage to the autonomic ganglia of the face and oral cavity causes burning pain in the area of innervation related to this ganglion, paroxysmalness, hyperemia, increased sweating, in the case lesions of the submandibular and sublingual nodes - increased salivation.
General characteristics of the autonomic nervous system: functions, anatomical and physiological features
The autonomic nervous system provides innervation to the internal organs: digestion, respiration, excretion, reproduction, blood circulation and endocrine glands. It maintains the constancy of the internal environment (homeostasis), regulates all metabolic processes in the human body, growth, reproduction, which is why it is called vegetable– vegetative.
Autonomic reflexes, as a rule, are not controlled by consciousness. A person cannot voluntarily slow down or increase the heart rate, suppress or increase the secretion of glands, therefore the autonomic nervous system has another name - autonomous , i.e. not controlled by consciousness.
Anatomical and physiological features of the autonomic nervous system.
The autonomic nervous system consists of sympathetic And parasympathetic parts that act on organs in the opposite direction. Agreed the work of these two parts ensures the normal function of various organs and allows the human body to adequately respond to changing external conditions.
·The autonomic nervous system has two divisions:
A) Central department , which is represented by vegetative nuclei located in the spinal cord and brain;
B) Peripheral department , which includes the autonomic nervous nodes (or ganglia ) And autonomic nerves .
· Vegetative nodes (ganglia ) are clusters of nerve cell bodies located outside the brain in different places of the body;
· Autonomic nerves come out of the spinal cord and brain. They first approach ganglia (nodes) and only then – to the internal organs. As a result, each autonomic nerve consists of preganglionic fibers And postganglionic fibers .
CNS GANGLION ORGAN
Preganglionic Postganglionic
Fiber fiber
Preganglionic fibers of the autonomic nerves leave the spinal cord and brain as part of the spinal and some cranial nerves and approach the ganglia ( L., rice. 200). Switching of nervous excitation occurs in the ganglia. Postganglionic fibers of the autonomic nerves depart from the ganglia, heading to the internal organs.
Autonomic nerves are thin, nerve impulses are transmitted through them at low speed.
The autonomic nervous system is characterized by the presence of numerous nerve plexuses . The plexuses include sympathetic, parasympathetic nerves and ganglia (nodes). Autonomic nerve plexuses are located on the aorta, around arteries and near organs.
Sympathetic autonomic nervous system: functions, central and peripheral parts
(L., rice. 200)
Functions of the sympathetic autonomic nervous system
The sympathetic nervous system innervates all internal organs, blood vessels and skin. It dominates during periods of body activity, stress, severe pain, and emotional states such as anger and joy. The axons of the sympathetic nerves produce norepinephrine , which affects adrenergic receptors internal organs. Norepinephrine has a stimulating effect on organs and increases the level of metabolism.
To understand how the sympathetic nervous system acts on organs, you need to imagine a person running away from danger: his pupils dilate, sweating increases, heart rate increases, blood pressure rises, bronchi dilate, breathing rate increases. At the same time, digestion processes slow down, the secretion of saliva and digestive enzymes is inhibited.
Divisions of the sympathetic autonomic nervous system
As part of the sympathetic part of the autonomic nervous system there are central And peripheral sections.
Central department represented by sympathetic nuclei located in the lateral horns of the gray matter of the spinal cord over the course of the 8th cervical to 3rd lumbar segments.
Peripheral department includes sympathetic nerves and sympathetic ganglia.
Sympathetic nerves emerge from the spinal cord as part of the anterior roots of the spinal nerves, then separate from them and form preganglionic fibers, heading to the sympathetic nodes. Relatively long ones extend from the nodes postganglionic fibers, which form sympathetic nerves going to internal organs, blood vessels and skin.
· Sympathetic nodes (ganglia) are divided into two groups:
· Paravertebral nodes lie on the spine and form right and left chains of nodes. The chains of paravertebral nodes are called sympathetic trunks . Each trunk has 4 sections: cervical, thoracic, lumbar and sacral.
·From nodes cervical spine Nerves depart that provide sympathetic innervation to the organs of the head and neck (the lacrimal and salivary glands, the muscle that dilates the pupil, the larynx and other organs). They also originate from the cervical nodes cardiac nerves, heading towards the heart.
· From nodes thoracic nerves extend to the organs of the chest cavity, cardiac nerves and pregnant(visceral) nerves, heading into the abdominal cavity to the nodes celiac(solar) plexuses.
·From nodes lumbar region depart:
Nerves going to the nodes of the autonomic plexuses of the abdominal cavity; - nerves that provide sympathetic innervation to the walls of the abdominal cavity and lower extremities.
· From nodes sacral region Nerves depart that provide sympathetic innervation to the kidneys and pelvic organs.
Prevertebral nodes are located in the abdominal cavity as part of the autonomic nerve plexuses. These include:
Celiac nodes, which are part of celiac(solar) plexuses. The celiac plexus is located on the abdominal aorta around the celiac trunk. Numerous nerves depart from the celiac ganglia (like the rays of the sun, which explains the name “solar plexus”), providing sympathetic innervation to the abdominal organs.
· Mesenteric nodes , which are part of the autonomic plexuses of the abdominal cavity. Nerves depart from the mesenteric nodes, providing sympathetic innervation to the abdominal organs.
Parasympathetic autonomic nervous system: functions, central and peripheral parts
Functions of the parasympathetic autonomic nervous system
The parasympathetic nervous system innervates the internal organs. It dominates at rest, providing “everyday” physiological functions. The axons of the parasympathetic nerves produce acetylcholine , which affects cholinergic receptors internal organs. Acetylcholine slows down organ function and reduces metabolic rate.
The predominance of the parasympathetic nervous system creates conditions for the human body to rest. Parasympathetic nerves cause constriction of the pupils, reduce the frequency and strength of heart contractions, and reduce the frequency of respiratory movements. At the same time, the work of the digestive organs is enhanced: peristalsis, secretion of saliva and digestive enzymes.
Divisions of the parasympathetic autonomic nervous system
As part of the parasympathetic part of the autonomic nervous system, there are central And peripheral sections .
Central department presented by:
brain stem;
Parasympathetic nuclei located in sacral part of the spinal cord.
Peripheral department includes parasympathetic nerves and parasympathetic ganglia.
Parasympathetic nodes are located next to organs or in their walls.
Parasympathetic nerves:
· Coming out brain stem as part of the following cranial nerves :
oculomotor nerve (3 a pair of cranial nerves), which penetrates the eyeball and innervates the muscle that constricts the pupil;
Facial nerve(7 a pair of cranial nerves), which innervates the lacrimal gland, submandibular and sublingual salivary glands;
Glossopharyngeal nerve(9 a pair of cranial nerves), which innervates the parotid salivary gland;
Sympathetic nervous system (from Greek sympathes - sensitive, susceptible to influence)
part of the autonomic nervous system of vertebrate animals and humans, consisting of sympathetic centers, right and left border sympathetic trunks located along the spine, ganglia (nodes) and nerve branches connecting the ganglia with each other, with the spinal cord and with effectors (See Effectors). The border sympathetic trunk is a chain of ganglia connected by internodal commissures; lies (right or left) on the vertebral bodies; each ganglion is also connected to one of the spinal nerves (See Spinal nerves). Fibers S. n. With. innervate all organs and tissues of the body without exception. Centers of S. science With. located in the thoracic and lumbar segments of the spinal cord. The sympathetic nuclei that form the lateral horns of the gray matter of the spinal cord are present only in 15-16 segments (from the last cervical or 1st thoracic to the 3rd lumbar segment). These nuclei are considered as a working apparatus, subordinate to suprasegmental formations, which are localized in the medulla oblongata (See Medulla oblongata) and the Hypothalamus, controlled by the cerebral cortex. A special place in the physiology of S. n. With. and coordination of the processes controlled by it is occupied by the Cerebellum. S. N. With. - efferent system that conducts impulses to various internal organs. Most authors deny the existence of their own afferent fibers in S. n. With. However, a number of works provide evidence of their existence. In the abdominal cavity, the fibers of S. n. With. pass as part of the greater, lesser and lumbar splanchnic nerves. Afferent nerves that conduct impulses from internal organs are represented in the cerebral cortex and subcortical ganglia. Sympathetic nerve impulses from the central nervous system to the executive organs follow a two-neuron pathway. The first neuron is located in the lateral horns of the spinal cord. The axons (processes) of the first neuron (preganglionic fibers) leave the spinal cord through the ventral roots of the corresponding segments and enter the mixed spinal nerves, from which, as part of the white connecting branches, they reach the corresponding node of the border sympathetic trunk, where some of the fibers end in synapses (See Synapses) on effector neurons; in this case, each preganglionic fiber contacts a large number of nerve cells (up to 30). Another part of the preganglionic fibers passes through the nodes of the borderline sympathetic trunk, without ending on its cells, and together with other fibers forms a number of nerves: the greater and lesser celiac, the lumbar celiac, entering the prevertebral sympathetic nodes. Some preganglionic fibers pass without interruption through these nodes, reaching the working organ, in the nerve ganglia of the walls of which they make a break. The second effector neuron is located in the peripheral sympathetic ganglia, its processes (postganglionic fibers) enter the innervated organ. The second neuron is located in the perivertebral (paravertebral) ganglia or in the prevertebral (prevertebral) ganglia (solar plexus nodes, inferior mesenteric node and others located at a great distance from the central nervous system, near internal organs). Postganglionic fibers enter the spinal nerve through the gray connecting branches, and in its composition they reach the innervated organ. Consequently, a break in each efferent sympathetic pathway in the arc that closes in the spinal cord occurs only once: either in the node of the border sympathetic trunk, or in nodes distant from the spine. Along with the sympathetic arc, which closes in the spinal cord, there are also short sympathetic reflex arcs, which close in the peripheral sympathetic ganglia (solar plexus, caudal mesenteric). The speed of excitation in sympathetic pre- and especially postganglionic fibers is many times lower than in somatic, i.e., bodily, and is about 1-3 m/sec. To cause effects in sympathetic fibers, a significantly greater force of stimulation is required. Originating in S. science. With. excitation, as a rule, involves a large number of neurons, so the effects of stimulation are not localized in any specific organ, but cover wide areas. The reactions that follow in response to irritation of sympathetic fibers are characterized by a relatively slow and prolonged nature, as well as a slow, prolonged attenuation of the ongoing processes. A number of substances (ganglionic blockers, ergot preparations) suppress the effects of stimulation of S. n. With. Some chemicals have the same effect on organs and tissues as irritation of the sympathetic nerves. This is due to the fact that when the sympathetic nerves are irritated, substances of similar action are released by the terminal formations of postganglionic sympathetic fibers (see Mediators). At the endings of all preganglionic fibers, as well as postganglionic fibers innervating the sweat glands, the mediator Acetylcholine is formed, at the endings of postganglionic fibers (with the exception of those innervating the sweat glands) - Norepinephrine. The influence of the sympathetic and parasympathetic nervous systems (See Parasympathetic nervous system) on the activity of an organ is often opposite. When sympathetic fibers innervating various organs are irritated, typical effects occur: acceleration and intensification of heart contractions, dilation of the pupil and mild lacrimation, contraction of smooth muscle fibers (pilomotors) that raise hair, secretion of sweat glands, scanty secretion of thick saliva and gastric juice, inhibition of contractions and weakening of the tone of the smooth muscles of the stomach and intestines (excluding the area of the ileocecal sphincter), relaxation of the muscles of the bladder and inhibition of contractions of the obturator sphincter, dilation of the coronary vessels of the heart, narrowing of small arteries of the abdominal organs and skin, small arteries of the lungs and brain, changes in the excitability of receptors, and also various parts of the central nervous system, increasing the strength of contractions of tired skeletal muscle, increasing its excitability and changing mechanical properties. Neurons S. n. pp., affecting the executive organs, are in a state of constant tonic excitation as a result of the interaction of unconditioned and conditioned reflexes carried out by the higher parts of the central nervous system. Tonic impulses S. n. With. are extremely important for maintaining the constancy of the internal environment of the body (Homeostasis a). Through sympathetic fibers and centers, a reflex relationship between all internal organs is ensured. Reflexes involving the action of S. n. pp., can occur due to irritation of both visceral and somatic nerves. Thus, with viscero-visceral reflexes, excitation arises and ends in the internal organs (irritation of the peritoneum causes a slowdown in cardiac activity). With visceromotor reflexes, excitation from the internal organs passes to the skeletal muscles (irritation of the peritoneum increases the tone of the abdominal muscles). Animals with completely removed border sympathetic trunks and ganglia (desympathized) outwardly differ little from normal ones, however, under certain loads (muscular work, cooling, etc.) they are less hardy. This indicates that S. n. pp., exerting a regulatory effect on the functional state of tissues, adapts (adapts) them to perform functions under given conditions (see Adaptive-trophic function). S. N. With. Stimulates mainly processes associated with the release of energy in the body and vigorous activity. Physiological manifestations of emotions (See Emotions) are associated primarily with the excitement of S. n. With. A. D. Nozdrachev. Great Soviet Encyclopedia. - M.: Soviet Encyclopedia.
1969-1978
.
See what the “sympathetic nervous system” is in other dictionaries:
SYMPATHETIC NERVOUS SYSTEM- see Autonomic nervous system. Large psychological dictionary. M.: Prime EUROZNAK. Ed. B.G. Meshcheryakova, acad. V.P. Zinchenko. 2003 ... Great psychological encyclopedia
SYMPATHETIC NERVOUS SYSTEM, one of the two parts of the AUTONOMIC NERVOUS SYSTEM, the second part is the PARASYMPATHETIC NERVOUS SYSTEM. Both systems are involved in the work of SMOOTH MUSCLES (involuntary contractions). Sympathetic nervous system... ... Scientific and technical encyclopedic dictionary
Big Encyclopedic Dictionary
A section of the autonomic nervous system that regulates the activity of the heart, lungs, intestines, gonads and other organs that do not depend (or depend to a very small extent) on the will of a person. Previously considered as a place of sympathy and love... Philosophical Encyclopedia
Anatomy of innervation of the autonomic nervous system. Systems: sympathetic (red) and parasympathetic (blue) Sympathetic nervous system (from the Greek ... Wikipedia
In invertebrate animals, little has been studied. In higher worms, ganglion cells and nerve fibers are found in various parts of the intestine, probably having sympathetic significance, but their relationship to the central system has not been clarified. At the highest... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Part of the autonomic nervous system, including nerve cells of the thoracic and upper lumbar spinal cord and nerve cells of the border sympathetic trunk, solar plexus, mesenteric ganglia, the processes of which innervate all organs... encyclopedic Dictionary
