Archives d'anatomie, d'histologie et d'embryologie normales et experimentales最新文献

Many features of the developing nervous system are visible in the intact human embryo, and a photographic atlas from 3-7 postovulatory weeks (stages 10-19) is provided. A number of features, such as the cerebellar plate, the cerebral vesicles, and the epiphysis cerebri, can be detected on external views at as early a stage as they have previously been recorded after microscopical examination. After 7 weeks it becomes increasingly difficult to identify features of the brain from the surface.

The study of young children's retrosternal lobular formations allowed us to distinguish different structures: lymph nodes, adipose lobules, and variable lymphoid formations. The arteries of the lymph nodes are either medullar, cortical or perforating, and the venous net is characterized by existence of perifollicular cortical corbels. The adipose lobules are often made of a mingling of white fat tissue and fetal fat tissue, and in the zones of foetal fat the vascular network is the most developed. The lymphoid formation are of variable structure and microcirculation. Some of them are represented by foetal fat lobules with scattered lymphoid cells, their microvascularization is comparable to microcirculation of fat tissue. Others, are characterized by few lymphoid cells and by development of the connective and reticular tissue; there, the anastomotic venous network is very dilated. Some formations are like lymph nodes, but their sinusal spaces are full of erythrocytes and their microcirculation is peculiar.

The subserous layer of the colon has, like the small intestine, a rich vascular network. The subserous arteries arise from the straight arteries and are directed towards the taeniae, the surface and free margin of the colon. They terminate at various levels and, by their collateral and terminal branches, form an anastomotic network of vessels whose morphology varies at the level of surface, taenia and the free margin of the colon. From this subserous arterial network arise branches destined to vascularise the muscularis, the fat of the colon and the greater omentum. The subserous venous network copies closely the morphology of the arterial network and is connected by large perforating veins to the submucous venous network.

This study shows different aspects of the innervation of some striated muscles. It appears that neuromuscular spindles are not present in all skeletal muscles. Some muscles of the oto-rhino-laryngological region lack spindles whilst their direct antagonists possess them. Amongst the muscles of the external and middle ear, the soft palate and the larynx having opposite actions, there is in each case one muscle which does not have any spindles. These muscles then have only motor innervation. The muscles which have neuro-muscular spindles are innervated by nerves composed of extra- and intrafusal motor fibres and proprioceptive fibres. The neuro-muscular spindles play a servo-braking role in the muscle where they occur. The oppose then a certain passive elongation of the muscle. At the same time and in this manner, they contribute in controlling and restraining the action of the muscles or of their opponents. This role is particularly important for the various muscles of the oto-rhino-laryngological region and is all the more important since the amplitude of the movements which they cause is very weak. The presence of these spindles increases also the sensitivity and the delicacy of the desired movement, for the behaviour of these muscles is very special. (See formula in text).

The subserous layer of the colon has, like the small intestine, a rich vascular network. The subserous arteries arise from the straight arteries and are directed towards the taeniae, the surface and free margin of the colon. They terminate at various levels and, by their collateral and terminal branches, form an anastomotic network of vessels whose morphology varies at the level of surface, taenia and the free margin of the colon. From this subserous arterial network arise branches destined to vascularise the muscularis, the fat of the colon and the greater omentum. The subserous venous network copies closely the morphology of the arterial network and is connected by large perforating veins to the submucous venous network.

The effects of the prolonged administration of ethidium bromide (EB), at a dose provoking a persistent inhibition of the incorporation of 3H-thymidine and 3H-uridine into the mitochondrial fraction, on the zona reticularis of ACTH-treated rats were investigated. Stereologically, it was found that EB induces noticeable decrease in the total amount of the mitochondrial compartment, mainly due to the reduction in the number of organelles per cell. High resolution autoradiography showed that the mechanism underlying this effects of EB probably involves both the inhibition of mitochondria proliferation and the acceleration of their breakdown as "intact units". These findings suggest that the ACTH-induced maintenance of the zona reticularis mitochondria growth involves mitochondrial DNA reduplication and transcription.

The vascularization of the mucosal and submucosal layers of the first and second duodenal segments of adult man is studied in 12 duodenums, in which the vascular system has been injected with gelatinous india ink. The submucosal layer of the duodenum constitutes a true vascular crossroad of two anastomotic networks, one arterial, the other venous, which morphology is completely superimposable. It differs from the jejunum and the ileum because the existence of the Brünner's glands in the submucosa which are vascularized by an important and characteristic capillary network. The arteries of the mucosa are tributary of the submucosal network. They leave precapillary arterioles which reach the Lieberkühn's glands, the Brünner's gland of the mucosa and the duodenal villi. There, they give rise in three capillary networks which are anastomosed at the base of the villi and within the lamina propria. The venous drainage of the mucosa flows into the submucosal venous network.

The corpus adiposum trigoni lumbalis is an adipose mass which is separated from the hypodermic fat pad by the fascia superficialis and placed on the trigonum lumbale and higher part of gluteal region. It gives some extension toward the flanks, the middle line of the body, the lower put of the gluteal region and is also very close to the subperitoneal fat pad. It's vascularization depends in greater part of it's own vessels, but also on vessels that irrigate the integument.

By studying the systematization of superficial veins in 70 human spinal cords, it is possible to recognize three different systems: anterior, posterior and lateral. The anterior spinal venous system is formed by an antero-medial trunk extending from the filum terminale to the medulla oblongata, and by two antero-lateral spinal trunks placed in the cranial part of the spinal cord. The posterior, spinal venous system is formed by a postero-medial spinal trunk, extending from the sacral spinal cord to the medulla oblongata, and by two postero-lateral venous trunks, in the thoracic region. The lateral spinal venous system forms an anastomotic system between the anterior and posterior venous systems; it is especially well developed in the lumbar enlargement. In this venous disposition, it can be recognized three types of networks: transversal, longitudinal and arciform, more or less intertwined according to the considered spinal levels.

When injected into chick eggs on the 8th day of incubation, gonadotropins (FSH + LH) were shown to stimulate the gonadal development on the 20th day of embryogenesis in both sexes. An increase in the testicular weight, in the seminiferous cord diameter as well as in germ and Sertoli cell number was observed in males. Similarly an increase in ovarian weight, in ovarian width, in cortical thickness and in the number of oocytes was reported in females. By contrast, thyrotropin (TSH) and adrenocorticotropin (ACTH) caused a noticeable decrease in gonadal development in both males and females as compared to the controls or to the gonadotropin-treated groups. It is concluded that the gonads of 8 days chick embryo have the capacity to respond to gonadotropic stimulation and not to the other hypophyseal hormones (TSH or ACTH). This suggests the possibility that at this early stage (8 days of incubation) the external specific hormone could induce its future hormone receptors.