Brain stem

The brainstem, cerebral stem or cerebral stem is formed by the midbrain, the annular pons (or pons) and the brainstem. medulla oblongata (also called medulla oblongata). It is the major communication route of the brain, spinal cord and peripheral nerves. It also controls several functions including breathing, heart rate regulation, and primary aspects of sound localization. Made up of gray and white matter.

Components

The gray matter forms nuclei within the white matter, which can be subdivided into three types:

1. Segmentary centers that represent the real origin of cranial pairs.
2. Nucles of the brain trunk that include:
   1. Relays of sensitive pathways.
   2. Origin of pathways of association of the brain stem.
   3. Origin of involuntary motorways (trapiramidal road).
3. Formation or reticular substance: set of neurons exercising an effect facilitator or inhibitor intervenes in several processes such as, for example, the state of sleep-vigilia.

Nuclei of origin of the cranial nerves

The somatomotor nuclei are divided into two columns:

• One dorsal, close to the middle line that is responsible for the motor inervation of the muscles of somtical origin (músculos motors extrínsecos of the eye and muscles of the tongue) and includes the nuclei:

1. Common oculomotor nerve (MOC) or III pair: located at the top of the mesencephalo, near the Silvio aqueduct. From this nucleus the nerve MOC or III will be left to the cranial.
2. Pathetic, IV pair or troclear nerve: in the lower part of the mesencephale. From it will come the pathetic nerve or IV cranial par whose fibers will be contralateral.
3. External eye motor (MOE) or VI par: located at the level of protuberance.
4. Major hypogloss or XII pair: at the bottom of the protuberance and upper part of the bulb; from it comes the XII cranial pair or hypogloss nerve that will inervate the muscles of the tongue.

• One ventral, located outside and forward of the previous and which provides inervation to the structures derived from the branchial arches and clefts and includes the nuclei:

1. Trigeminal motor or chewing core: it is the highest of protuberance. It comes from nerve fibers that make up the chewing nerve that will be incorporated into the trigemino or V pair cranial.
2. Facial or VII par: in the lower part of the protuberance. Here comes the facial nerve or VII cranial pair. When you leave, your axon first heads to the middle line, surrounds the nucleus of the MOE and thus forms the first knee of the facial (you have to take into account that this fact is given on the left side and in the right). After this it comes out of the brain trunk laterally.
3. Ambiguous: constituted by two united cores. It extends along the bulb and the protuberance (less in the latter). It is the origin of the somatomotor fibers, from top to bottom, of the glosopharyngeum, pneumogastric, (or vague).
4. Accessory or spinal: is the lowest. From it comes the accessory nerve (XI par cranial). Some authors consider it as a constituent of the ambiguous core. It will continue in the cervical spinal cord with the spinal nerve core.

Did you mean: Los núcleos somatosensitivos donde, al igual que en los anteriores, también pueden describirse dos columnas:

• A dorsal, which includes the cores:

1. statoacoustic, which can be subclassified in vestibule nuclei, related to the balance, are located at the external angle of the floor of the fourth ventricle where the eminence or acoustic trigone forms, are mainly described 3 (Schwalbe or main nucleus, Deiters and Bechterew) and cochterew nuclei, are two the first nucleus of auditoral and
2. nucleus of the solitaire fascicle, corresponds to the outer white wing of the fourth ventricle floor and is the actual origin of the Wrisber intermediary (VII bis); of the glosopharynge (IX) and finally the vago nerve (X); the upper part, where the fibers of the VII bis and the IX are originated, forms the nucleus;

• a ventral, which includes the core of the trigemino (V par) or Rolando gelatinous nucleus. It extends along the trunk of the brain, from the lower section of the calota of the cerebral peduncles to the lower part of the bulb where it continues with the gelatinous substance of Rolando. It has an average part of greater diameter at the level of the protuberance being attached to the ends. It is the first relay of the sensitive fibers of the V pair.

Did you mean: Los núcleos visceromotores forman una columna que se encuentra hacia afuera de las columnas previas y engloba lo siguiente:

• The nuclei of the intrinsic motility of the eye that are the medium core of Perlia (convergence of the look) and the nuclei of Edinger (adacation and pupil contraction).
• The lacrimomuconasal nucleus gives fibers that are added to the seventh pair and control the tear and mucous secretion of the nostrils.
• The salival nuclei:
  • Superior, is the origin of the visceral fibers of Wrisberg's intermediate nerve (VII bis) that inerve the submaxillary and sublingual glands.
  • Inferior, they add to the fibers of the glyosopharyngeus (IX) that inerve the paralytic gland.
• The cardioneumoentric nucleus is the origin of the heart, respiratory and digestive fibers of the X par.

Did you mean:

Y, por último, los núcleos viscerosensitivo, de los cuales el único bien diferenciado es el núcleo dorsal del vago que se corresponde con el ala gris del piso del cuarto ventrículo.

Brainstem association pathways

They are fibers that connect different nuclei to each other within the brain stem, although some of them can reach the spinal cord or even the cerebellum. There are pathways that interconnect the right and left centers that are transverse:

1. Internuclear cross-sectional oculocephalogiras which associates the nuclei of the common and external motor nerves right and left allowing the conjugated movement of the eyes.

2. Arciform fibers of the bulb which belong to the pathways, and pathways vertical, the latter represented mainly by two groups of fibers called:

1. Cintilla Longitudinal Posterior or Medium Longitudinal phase: which includes fibers ranging from the proximity of the third ventricle floor or the upper end of the Silvio aqueduct, more precisely from the core of Darkschewitsch, to the cervical marrow and is especially related to the reflex control of the movements of the head and the eyes. It runs through the middle line, at the peduncular level it does it immediately ahead of the Silvio aqueduct and at the bulboprotuberancial level it lies ahead of the gray substance of the 4th ventricle floor. Understand:

• Fibers born in vestibular cores superior or of Bechterew and medial or by Schwalbe forming what is known as Van Gehuchten vestibulomesencephalic fascicle or vestibulooculogiro. Fibers originating from upper vestibular core ascend by the homolateral Medium Longitudinal phase towards the oculomotor nuclei (III, IV and VI), some fibers cross the middle line towards the counterlateral oculomotor complex in the flow part of the mesencephale; while those born from the middle vestibular nucleus are projected bilaterally towards the nuclei of the extraocular muscles with counterlateral predominance, giving in addition to descending fibers that In this way, a reflection of the coordination of the ocular movements with those of the head and neck and of oculocephalus response to nervous stimuli originated in the semicircular ducts of the inner ear is formed. Cross fibers exert an excitatory effect and direct effect an inhibitory effect.

• You make fibers originated in the internuclear neurons of the VI cranial pair, cross the middle line and end in the nucleus of the III conlateral cranial pair, more precisely in the neurons that inerve the internal rectum muscle, providing the neural connection that allows the conjugated movements of the eyes in lateral form. Some of the ascending fibers continue beyond the oculomotor cores to end in the interstitial core of Cajal

• Fibers that are born in the hypothalamic vegetative nuclei (medial and periventricular portion) and end up in the periacueductal gray substance of the mesencephale and the ceiling. Some fibers can reach bulboprotuberanciales vegetative nuclei, such as the spinal nucleus and the laterodorsal and dorsal tegmentary nuclei.Schütz fascicle or longitudinal dorsal).

• Fibers that come from the mummary tubers and are distributed by the reticular substance of the calota (dorsal and ventral cores of the calota) and the protuberance (Gudden fascicle or mamilotegmental).

• And finally, fibers that are born in the core of Darkschewitsch and end in the core of the VI par.

2. Central calota phase: It is part of the extrapiramidal pathways. It is located on the front and outside of the medial longitudinal belt. Contains fibers descendant which are directed from the mesencephalic nuclei (red nucleus) and probably from the optocurrencies to the reticular substance of the bulb, the lower olive complex and the upper cervical marrow; and Amount that depart from the bulbar reticular formation (cellular gigantic reticular core) and end in the thalamic rostral nuclei. These are the last ones that would intervene in awakening.