The trapezoid body is an integral part. Topic: Central nervous system
1 - basilar sulcus
2 - trapezoid body
3 - base of the bridge
4 - bridge tire
5 - transverse fibers of the bridge
6 - longitudinal fibers of the bridge
7 - rhomboid fossa
8 - superior cerebellar peduncle
9 - reticular formation
10 - medial loop
11 - abducens nerve
12 - facial nerve
13 - vestibulocochlear nerve
14 - glossopharyngeal nerve
15 - vagus nerve
16 - accessory nerve
17 - hypoglossal nerve
Top olive.
In the tire of the bridge, a paired upper olive core, in which part of the auditory fibers switches, and the nuclei of the reticular formation are also located. In the upper olive, auditory information is interrupted in order to process it. From here, descending fibers begin, heading to the inner ear to the receptors.
vestibular nuclei. balance system.
The vestibular nuclei are an organ that fixes a change in the position of the body in space and is located in the inner ear. Excitation of the vestibular nuclei occurs under the action of an adequate stimulus acting on the vestibular apparatus.
Also, from the vestibular nuclei of the medulla oblongata there is a path to the so-called medial bundle, directed towards the spinal cord. This bundle performs an important function: it connects together all the nuclei of the nerves involved in the regulation of the activity of the muscles of the eyeball. The signals coming from the vestibular nuclei enter the longitudinal medial bundle, due to which, when the vestibular apparatus is activated, the phenomenon of nystagmus occurs (involuntary oscillatory eye movements with a high frequency (up to several hundred per minute)). Thus, when the vestibular apparatus is irritated, a redistribution occurs muscle tone and a change in the activity of the muscles of the eyeball, as a result of which the animal is able to maintain balance and direct its gaze in the right direction.
The neurons of the vestibular nuclei also have the ability to respond to changes in the position of the limbs, body turns, signals from internal organs, i.e., to synthesize information coming from different sources. At the same time, they provide control and management of various motor reactions.
The most important of these reactions are vestibulospinal, vestibulo-vegetative and vestibulo-oculomotor. Vestibulospinal influences through the vestibulo-, reticulo- and rubrospinal tracts provide changes in neuronal impulses at segmental levels of the spinal cord. Thus, a dynamic redistribution of skeletal muscle tone and reflex reactions necessary to maintain balance are carried out. The cerebellum is responsible for the phasic nature of these reactions: after its removal, the vestibulospinal influences become predominantly tonic. During voluntary movements, the vestibular influences on the spinal cord are weakened.
The central axons of the primary sensory neurons of the vestibular ganglion terminate at the neurons of the vestibular nuclei. These nuclei represent a single functional complex, which combines afferent information from the vestibular ganglia and from proprioceptors; this afferentation determines the nature of the activity of the neurons of the vestibular nuclei.
The fibers of the vestibular nerve separate before approaching certain cell groups of the vestibular nuclei, where the second neurons begin. Some of its fibers transmit impulses directly, without switching to the cerebellum. The vestibular nuclei have a two-way connection with the cerebellum.
The complex of vestibular nuclei includes:
Superior vestibular nucleus (Bekhterev's nucleus)
- Lateral vestibular nucleus (Deiters nucleus)
- Medial vestibular nucleus (Schwalbe's nucleus)
- Inferior vestibular nucleus (Roller's nucleus)
Vestibular neurons send their fibers to:
-spinal cord
-trunk
-cerebellum
Projections above the cerebellum have not been proven, i.e.representation of the vestibular system has not been proven either in the Thalamus or in the cortex hemispheres
(see the first table of the 8th lecture).
Native bridge cores.
The gray matter of the base of the pons is represented by bridge's own cores. These nuclei play the role of intermediate communication centers of the cerebral cortex with the cerebellum, i.e. their neurons take in information and switch it to the cerebellar cortex. There are a lot of these nuclei (about 20 thousand), these are small inclusions of gray matter in the white matter (the base of the bridge is represented by both white and gray matter, in contrast to the base of the medulla oblongata).
Conducting paths of the bridge:
- corticospinal fibers
- cortico-bridge fibers
- corticobulbar fibers
Red core.
The red nucleus is a structure of the midbrain, located symmetrically in the thickness of the legs of the brain under the central gray matter. It is a large accumulation of nerve cells, playing along with other formations key role in the extrapyramidal (automatic, without the participation of consciousness) system. The red nucleus is closely connected with the structures of the cerebellum.
The neurons of this nucleus receive information from the cerebral cortex and cerebellum, that is, all information about the position of the body in space, the state of the muscular system, and the skin. The influence on the alpha motor neurons of the spinal cord is carried out with the help of the rubrospinal tract. The rubrospinal tract begins from the cells of the red nucleus, located in the cortex of the legs of the brain. Activation of the neurons of the red nucleus causes an excitatory postsynaptic potential in the motor neurons of the flexor muscles, and in the motor neurons of the extensor - inhibitory postsynaptic potentials. In this respect, the rubrospinal tract is similar to the corticospinal tract.
Tectal area:
- a reaction of general startle (a sharp increase in the modality of any stimulus: there was nothing and suddenly a sharp effect on the sense organ);
- orienting reflex - focuses on the source of the stimulus, it is suppressed (when the stimulus is repeated, when it is insignificant, it is suppressed (we stop responding to it), suppression requires the participation of the cerebral cortex; it is based on the sentinel reflex;
TRAPEZOID BODY
(corpus trapezoideum, pna, bna; corpus trapezoides, jna) a flat bundle of transverse fibers of the auditory pathway, located on the border of the upper and lower parts of the brain bridge (pons varolii).
Medical terms. 2012
See also interpretations, synonyms, meanings of the word and what is TRAPEZOID BODY in Russian in dictionaries, encyclopedias and reference books:
- BODY
BOW - see the shaft of the bow ... - BODY The Illustrated Encyclopedia of Weapons:
SHUTTER - see stem ... - BODY in the Slang Dictionary of Sevastopol:
1. A drunk person 2. A curvy girl sunbathing on ... - BODY in the Dictionary of Analytical Psychology:
(Body; Koegeg) - the material substance of the individual. The body was considered by Jung as an expression of the "physical materiality of the mental" (CW 9, par. 392). That the body... - BODY in the Dictionary of Postmodernism:
- a term of traditional aesthetic and socio-humanitarian knowledge (see also Corporality), which acquires an immanent categorical status in the conceptual complex of postmodern philosophy. AT … - BODY in the Dictionary of Yoga:
(Body) See Deha; Sharira; Upadhi; Physical body; Subtle Body; Karana Sharira ... - BODY in the Dictionary of Economic Terms:
(slang) - property in the hands of trustees, principal or ... - BODY in Medical terms:
- see Tel-… - BODY in encyclopedic dictionary:
, -a, pl. bodies, bodies, bodies, cf. 1. A separate object in space, as well as a part of space filled with matter, somehow. substance... - BODY
DAM BODY, osn. part of the dam (without additional devices - ponura, water break, screen, etc.), perceiving pressure ... - BODY in the Big Russian Encyclopedic Dictionary:
BODY geometric, any limited part of space together with its boundary (for example, a ball, ... - BODY in the Full accentuated paradigm according to Zaliznyak:
those "lo, bodies", those "la, those" l, those "lu, bodies" m, those "lo, bodies", those "scrap, bodies" mi, those "le, ... - BODY in the Dictionary of Epithets:
Trunk, human body. About the size, size, severity; about a strong, slender or weak, frail body; about the state of the body. Athletic, powerless, heroic, ... - BODY in the Dictionary of the Great Russian language of business communication:
Rostelecom. (Dictionary of proper names - names ... - BODY in the Popular Explanatory-Encyclopedic Dictionary of the Russian Language:
-a, pl. tel "a, tel, tel" am, s. 1) Something material, material, visible and tangible, occupying a limited space; separate object in space. … - BODY in the Dictionary for solving and compiling scanwords:
Wrapped in… - BODY in the Dictionary of synonyms of Abramov:
|| keep in a black body, a dead body, acquire a body, not guilty either in soul or body, fall off the body, get drunk until ... - BODY in the dictionary of Synonyms of the Russian language:
alloplant, apothecium, bismalite, harpolith, dike, diapirus, intrusion, cleistocarp, comet, cone, corpus, laccolic, lopolith, lofolite, macrobody, microbody, organism, remains, perithecium, pycnid, … - BODY in the New explanatory and derivational dictionary of the Russian language Efremova:
cf. 1) a) A separate object in space. b) A part of space bounded by a closed surface. c) A substance characterized by a certain set of properties; chemical ... - BODY in the Complete Spelling Dictionary of the Russian Language:
body, -a, pl. bodies, bodies... - BODY in the Spelling Dictionary:
body, -a, pl. tel'a, tel, ... - BODY in the Dictionary of the Russian Language Ozhegov:
! separate object in space Solid, liquid and gaseous bodies. Geometric p. body is a separate object in space, as well as a part ... - BODY in Modern explanatory dictionary, TSB:
geometric, any limited part of space together with its boundary (for example, a ball, ... - BODY in the Explanatory Dictionary of the Russian Language Ushakov:
body, pl. bodies, bodies, bodies (cf. bodies), cf. 1. Limited space filled with some kind of. matter, substance (physical). All bodies are divided into... - BODY in the Explanatory Dictionary of Efremova:
body cf. 1) a) A separate object in space. b) A part of space bounded by a closed surface. c) A substance characterized by a certain set of properties; … - BODY in the New Dictionary of the Russian Language Efremova:
cf. 1. A separate object in space. ott. A part of space bounded by a closed surface. ott. A substance characterized by a certain set of properties; chemical element. … - BODY in the Big Modern Explanatory Dictionary of the Russian Language:
I cf. 1. A separate object in space. ott. trans. The main part, the body of something (a ship, an aircraft, an artillery gun, a machine gun, and ... - EUCHARIST OFFER in the Orthodox Encyclopedia Tree:
Open Orthodox Encyclopedia "TREE". When I hear the mention of the Body of Christ, I understand what was said in one sense, and the unbeliever - ... - LATERAL LOOP in Medical terms:
(lemniscus lateralis, pna, bna, jna; syn. auditory loop) a collection of fibers of the second neurons of the auditory pathway, which, starting in the nuclei of the cochlear part ... - ROD in the Big Encyclopedic Dictionary:
long metal semi-finished product - a blank for obtaining parts by plastic deformation or cutting. The cross section of the bar is round (most often), hexagonal, ...
The following parts are distinguished in the bridge (Fig.4.). These are the base (basis) (ventral part), the trapezoid body (corpus trapezoideum), the tire (dorsal part) (tegmentum).
The trapezoidal body (9) is the boundary between the base and the tire. Here are the neurons of the auditory pathway. The continuation of the trapezoid body at the exit from the bridge is the auditory loop, lemniscus lateralis (12).
The auditory or lateral loop consists of crossed and non-crossed nerve conductors of the auditory pathway. Axons of 2 neurons of the auditory pathway (cells of the vestibular nuclei) follow the surface of the rhomboid fossa from its angle to the median sulcus, forming the brain stripes, striae medullaris. Moving to the opposite side, these fibers join the fibers of the trapezoid body and form a lateral or auditory loop - lemniscus lateralis.
The base of the pons is composed of both white and gray matter.
The gray matter is represented by its own nuclei of the bridge (nuclei proprii pontis) (11). white matter- longitudinal and transverse fibers.
The longitudinal fibers of the bridge (fibrae pontis longitudinales) consist of pathways that run from the cerebral cortex to the nuclei of the bridge, cerebellum and spinal cord (tratus corticospinalis, tratus corticonuclearis, tratus cortico-ponto-cerebellaris).
The transverse fibers of the bridge (fibrae pontis transversus) form the bridge-cerebellar pathways (tratus ponto-cerebellaris) as part of the middle cerebellar peduncles. They follow from the nuclei of the bridge to the cerebellum. Thanks to these fibers, vestibular functions are regulated, namely, the coordination of movement and the position of the body in space are controlled.
The pontine tire, together with the medulla oblongata, is involved in the formation of the rhomboid fossa. Localized here: mesh formation, anterior spinal cerebellar tract, lateral and medial loops (10, 12), superior olive (6) (refers to the auditory analyzer), trigeminal nucleus (5), abducens (1), facial (2), vestibulocochlear nerves (4).
The fibers of the ascending sensory pathways (medial and spinal loops) pass through the pons operculum. At the level of the bridge, the fibers of the trigeminal (trigeminal) loop, formed by the processes of the second neurons that lie in the sensory nucleus of the trigeminal nerve, also join them.
Thus, the nerve fibers that make up the spinal, medial and trigeminal loops carry sensory information to the diencephalon and telencephalon and are called lemniscal tracts.
The cranial nerves from the V to VIII pair emerge from the bridge.
V pair, trigeminal nerve, n. trigeminus, mixed.
Motor fibers are axons of the motor nucleus of the trigeminal nerve located in the bridge. Sensitive - represented by the central processes of pseudo-unipolar cells located in the sensitive node of the crescent shape - the trigeminal, Gasser node (ganglion trigeminale). This node lies on the anterior surface of the pyramid of the temporal bone, the central processes of its cells end on the neurons of three nuclei: the midbrain (nucleus mesencephalicus), the bridge (nucleus pontinus), the nucleus of the spinal cord of the trigeminal nerve, (nucleus tractus spinalis n. Trigemini). The trigeminal nerve leaves the substance of the bridge on the border with the middle cerebellar peduncle with two roots - sensory and motor. The sensitive root represents the totality of all the central processes of the cells of the trigeminal node. They form 3 branches: ophthalmic, maxillary and mandibular nerves. The motor fibers attach only to the mandibular nerve.
The ophthalmic nerve enters the orbit through the superior orbital fissure, innervates the contents of the orbit, the upper eyelid, the skin of the forehead and crown, the mucous membrane of the upper part of the nasal cavity and the paranasal sinuses. The maxillary nerve exits through a round opening into the pterygopalatine fossa. It innervates the gums and teeth of the upper jaw, the mucous membrane of the palate, nasal cavity and maxillary sinus, the skin of the nose and cheeks. The mandibular nerve contains sensory and motor fibers, passes through the foramen ovale, innervates the gums and teeth of the lower jaw, the mucous membrane of the tongue, the skin of the cheeks, chin, the lower part of the auricle and the external auditory canal. Motor fibers innervate the masticatory muscles.
VI pair - abducens nerve (n.abducens ), motor. It is formed by the axons of the neurons of the motor nucleus located in the bridge. The nerve emerges from the transverse groove between the pons and the pyramid of the medulla oblongata and goes to the orbit. There it passes through the superior orbital fissure. This nerve innervates the lateral rectus muscle of the eyeball.
VII pair - facial nerve (n. facialis), mixed.
Motor fibers are axons of the motor nucleus, located deep in the bridge under the facial tubercle. Sensory fibers are the central processes of pseudo-unipolar nerve cells of the sensory ganglion (ganglion geniculi) located in the bend of the facial nerve canal (in the thickness of the temporal bone pyramid). In the bridge, sensory fibers terminate at the neurons of the nucleus of the solitary pathway (nucleus tractus solitarius). The preganglionic parasympathetic fibers of the facial nerve originate from two parasympathetic (secretory) nuclei - the superior salivary nucleus (nucleus salivatorius superior) and the lacrimal nucleus (nucleus lacrimalis), which lie in the pons operculum. The facial nerve exits the pons at the cerebellopontine angle. The cranial cavity leaves through the canalis stylo-mastoideum. Innervates all facial muscles, some muscles of the neck, stapedius muscle, taste buds in the anterior 2/3 of the tongue, submandibular and sublingual salivary glands, mucous glands of the palate, nasal cavity, lacrimal gland.
VIII pair, vestibulo-cochlear nerve (n.vestibulo-cochlearis)- a nerve of special sensitivity (auditory and vestibular), consists of two parts: cochlear and vestibular. Each part has its own sensitive node. The cochlear node (cochlear node) is located in the spiral canal of the cochlea. The peripheral processes of the cells of this node end on the cells of the spiral (Korti) organ, and the central processes go to the ventral and dorsal cochlear nuclei of the pons. The totality of the central processes of the bipolar cells of the cochlear node is the cochlear part (pars cochlearis) of the VIII pair. The vestibular node is located at the bottom of the internal auditory meatus. The peripheral processes of the cells of this node form nerves ending at the vestibular receptors of the auditory crests and spots. The central processes of the bipolar cells of the vestibular ganglion make up the vestibular part of the VIII pair and end on the vestibular nuclei of the pons. From the receptors of the inner ear, the vestibulocochlear nerve goes to the internal auditory canal, exits it, enters the substance of the bridge in the region of the cerebellopontine angle, lateral to the facial nerve.
Bridge functions:
1. Conductor function - fibers pass in the ascending and descending direction.
2. Place of exit of the cranial nerves from the V-VIII pair.
Rice. 4. Cross section of the bridge
1. Nucleus nervi abducens (abducens nucleus)
2. Nucleus nervi facialis (nucleus of the facial nerve)
3. Stria medullaris (brain strips)
4. Nucleus cochlearis dorsalis (posterior auditory nucleus)
5. Nucleus tractus spinalis nervi trigemini (spinal nucleus of the trigeminal nerve)
6. Oliva superior (top olive)
7. Nucleus cochlearis ventalis (anterior auditory nucleus)
8. Tractus pyramidalis (pyramidal tract)
9. Corpus trapezoideum (trapezoid body)
10. Lemniscus medialis (medial loop)
11. Nucleus proprius pontis (pontis own nucleus)
12. Lemniscus lateralis (lateral loop)
The bridge (pons) is an elevation located between the medulla oblongata and midbrain, 25–27 mm long. Its lower border is the pyramids and olives of the medulla oblongata, the upper one is the legs of the brain, the lateral one is the line passing between the roots of the trigeminal and facial nerves. On the dorsal side, the upper border of the bridge is the upper cerebellar peduncles (pedunculi cerebellares superiores) and the upper medullary velum (velum medullare superius), and from below is a deep horizontal groove, from which, starting from the main groove, the roots of the efferent (VI pair), facial ( VII pair) and auditory (VIII pair) nerves.
The bridge is divided into front and rear parts. The anterior part of the bridge (pars anterior pontis) is convex and formed by transverse nerve fibers connecting the cells of the cortex of the cerebral hemispheres with the nuclei of the bridge (nucll. pontis) and then with the cerebellar cortex. Together with them, the fibers from the cerebellar cortex to the cerebral cortex go in the opposite direction. These fibers cover the perpendicular bundles of the pyramidal path (Fig. 465), and then in the lateral parts of the bridge are collected in the middle cerebellar peduncles (pedunculi cerebellares medii). Along the midline of the bridge between the elevations formed by the fibers of the pyramidal path, there is a basilar groove (sulcus basilaris), in which the artery of the same name lies.
465. Diagram of the arrangement of conductive paths and nuclei on the cross section of the bridge.
1 - nuclei of the V pair; 2 - nuclei of the VIII pair; 3-tr. rubrospinalis; 4-tr. spinocerebellaris anterior; 5-tr. spinocerebellaris posterior; 6-tr. spinothalamicus lateralis; 7 - VII pair; 8 - VI pair; 9-tr. corticospinalis (pyramidalis); 10 - fast. longitudinalis medialis; 11-tr. spinothalamicus anterior: 12 - tr. tectospinalis; 13-tr. reticulospinalis.
The dorsal part of the bridge is thinner and participates in the formation of the upper part of the rhomboid fossa. In the dorsal part of the bridge are the nuclei of the V, VI, VII, VIII cranial nerves, the reticular formation, and the superior olive. The latter is associated with the auditory nuclei and has connections with the reticular formation of the medulla oblongata and midbrain.
The sensory and motor nuclei of the trigeminal nerve (V pair) are located in the upper part of the bridge. The sensitive nucleus (nucleus sensorius n. trigemini) is the site of switching of the processes of the cells of the trigeminal ganglion. The motor nucleus (nucl. motorius n. trigemini) consists of small pyramidal cells that innervate the masticatory muscles.
The nucleus of the abducens nerve (nucl. n. abducentis) (VI pair) is located in the lower part of the bridge near the midline.
The nucleus of the facial nerve (nucl. n. facialis) is formed by motor cells that innervate the mimic muscles. They are arranged in a mesh formation. The fibers of the nucleus form a knee that goes around the nucleus of the abducens nerve. Behind the motor nucleus of the facial nerve lies the superior salivary nucleus (nucl. salivatorius superior), where fibers begin to innervate the lacrimal, sublingual, and submandibular glands. Lateral to the superior salivary nucleus is the nucleus of the solitary pathway (nucl. tr. solitarii), (the nucleus of the VII pair), which has the form of a column reaching the medulla oblongata. In the nucleus, the sensitive fibers of the cells of the knee node (gangl. geniculi), which are conductors of taste sensations, terminate.
The nuclei of the vestibulocochlear nerve (n. vestibulocochlearis) are located in the lower lateral part of the back of the bridge.
Olives. The upper olive (oliva superior) has nuclei lying in the lateral sections of the bridge at the level of the trapezoid body, that is, on the border of its ventral and dorsal parts.
The reticular formation (formatio reticularis) has several nuclei, predominantly oriented in the plane of the cross section (Fig. 465).
1. Lateral reticular nucleus(nucl. reticularis lateralis) lies laterally and below the lower olive. Sends its fibers through the opposite lower cerebellar peduncles to the cerebellum.
2. The reticular core of the pons (Bechterew) (nucl. reticularis tegmenti pontis) surrounds the own core of the bridge. Some of its fibers reach the cerebellar worm, others, crossing, end in the cerebellar hemispheres.
3. Paramedial reticular nucleus (nucl. paramedialis) is medial and dorsal to the lower olive. Part of the fibers crosses and reaches the vermis, hemispheres and tent nucleus of the cerebellum.
4. Reticular giant cell nucleus (nucl. retucularis gigantocellularis) represents 2/3 of the volume of the reticular formation. It is located dorsal to the superior olive, at the top it extends to the nucleus of the facial nerve. Long processes of cells of the giant cell nucleus reach the overlying and underlying parts of the brain.
5. The caudal reticular nucleus (nucl. reticularis caudalis) is located above the previous one.
6. The oral reticular nucleus (nucl. reticularis oralis) is located on the border with the midbrain. Continues into mesencephalic reticular formation. The fibers of the caudal and oral nuclei, together with the fibers of the giant cell nucleus, form ascending and descending fiber systems.
The trapezoidal body (corpus trapezoideum) is located between the anterior and posterior parts of the bridge in the form of a 2-3 mm wide sill. It is formed by the own nuclei of the trapezoid body (nucl. proprius), as well as by the fibers of the ventral and dorsal auditory nuclei (nucl. cochleares anterior et posterior). The processes of the cells of the nuclei of the trapezoid body, the anterior and posterior nuclei are combined into a lateral loop (lemniscus lateralis), which also has its own nucleus (nucl. lemniscus lateralis). The trapezoid body, the anterior and posterior nuclei, and the lateral loop are involved in the formation of the auditory pathway.
Age features. The bridge in newborns lies 5 mm above the back of the Turkish saddle. By the age of 2-3, it descends onto the slope of the skull. The nuclei of the cranial nerves are well differentiated, the fibers of the cortical-spinal tract are covered with myelin by the age of 8.