Search results for "Cervell"
showing 10 items of 32 documents
Papel de la eminencia talámica, el sistema olfativo principal y el sistema olfativo accesorio en la maduración sexual del encéfalo y las manifestacio…
2014
El desarrollo de sistema olfativo y la diferenciación sexual del encéfalo, tanto en el hombre como en los animales, están estrechamente relacionados. Actualmente, se describe la imbricación entre la formación del sistema olfativo principal y la migración de las neuronas que sintetizan la hormona liberadora de gonadotrofinas (GnRF). Estas neuronas GnRF se desplazan por los nervios olfatorios, desde la parte medial del epitelio nasal al bulbo olfatorio, continúan por el encéfalo rostral hasta alcanzar el hipotálamo anterior. Por otro lado, el síndrome de Kallmann es un trastorno genético en el cual se combina el hipogonadismo hipogonadotrópico y la anosmia. El hipogonadismo se caracteriza por…
Functions of Astrocytes under Normal Conditions and after a Brain Disease
2023
In the central nervous system (CNS) there are a greater number of glial cells than neurons (between five and ten times more). Furthermore, they have a greater number of functions (more than eight functions). Glia comprises different types of cells, those of neural origin (astrocytes, radial glia, and oligodendroglia) and differentiated blood monocytes (microglia). During ontogeny, neurons develop earlier (at fetal day 15 in the rat) and astrocytes develop later (at fetal day 21 in the rat), which could indicate their important and crucial role in the CNS. Analysis of the phylogeny reveals that reptiles have a lower number of astrocytes compared to neurons and in humans this is reversed, as …
Hemispheric differences in specificity effects in talker identification
2010
In the visual domain, Marsolek and colleagues (1999, 2008) have found support for two dissociable and parallel neural subsystems underlying object and shape recognition: an abstract-category subsystem that operates more effectively in the left cerebral hemisphere (LH), and a specific-exemplar subsystem that operates more effectively in the right cerebral hemisphere (RH). Evidence of this asymmetry has been observed in priming specificity for linguistic (words, pseudoword forms) and nonlinguistic (objects) stimuli. In the auditory domain, the authors previously found hemispheric asymmetries in priming effects for linguistic (spoken words) and nonlinguistic (environmental sounds) stimuli. In …
Thyroid hormones and the central nervous system of mammals (Review)
2008
Abstract. The thyroid hormones (THs) L-thyroxine (T4) and L-triiodothyronine (T3) have a profound influence on the development and maturation of the mammalian brain, both before and after birth. Any impairment in the supply of THs to the developing nervous system leads to severe and irreversible changes in both the overall architecture and functions of the brain and causes, in humans, neurological and motor deficits known as cretinism. Pronounced neurological symptoms are also commonly observed in adult patients suffering from both hyperthyroidism and hypothyroidism, and it has recently emerged that certain symptoms might result from the reduced brain uptake, rather than the insufficient pr…
IL FATTORE IDROSTATICO
2007
La pressione idrostatica di un fluido è l’aumento della pressione in profondità rispetto a quella di superficie. Nelle arterie e vene cerebrali la pressione idrostatica del sangue se soggetta a continue oscillazioni può danneggiare il sistema capillare interposto e incidere negativamente sugli scambi di ossigeno e altre sostanze con il tessuto nervoso circostante. Il controllo vasomotorio del sistema nervoso autonomo è inefficace determinando una contrazione lenta e duratura nel tempo a livello delle arteriole di medio e piccolo calibro. Esiste perciò un importante fattore di bilanciamento della pressione sanguigna a livello cranico in grado di contenere la pressione idrostatica eccessiva: …