摘要:

In the second cleavage mitosis of newt embryos at anaphase, disassembly of mitotic spindle fibres, mediated by the ‘plus’ ends of their microtubules, results in equatorial division into two half-spindles. Yolk-filled cytoplasm invades the area free of fibres and is itself penetrated by antiparallel fibres from asters, which have become nucleated at opposite poles. These fibres immediately supplant the mitotic spindle; they participate in the lengthening of the interpolar distance and in the positioning of the newly formed daughter nuclei. The mechanisms of these successive phenomena must be considered in order to understand the complexities of the cell cycle in early mito

ISSN:1422-6405    

DOI:10.1159/000147998

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

The nutritional blood vessel system in the anagen (growing) vibrissal follicle consists of a rete capillare papillae pili, rete capillare bulbi pili, rete capillare folliculi pili, and rete capillare canalis pili. Due to degeneration of papilla and bulb during the sinus hair cycle, the basal capillary networks are absent in the telogen (resting) vibrissal follicle. Thus, nonpermanent and permanent capillary networks have to be distinguished. A functional blood vessel system originates from arterioles that enter the sinus cavernosus at its basolateral side. Blood flow continues into the sinus anularis. Efferent capillaries, originating from the apical-axial area of the sinus anularis, build up a separate network for the collection of blood from the sinuses. These capillaries continue towards the dermis, contribute to the nutritional vascularization of the sebaceous gland, and finally connect with the subepidermal capillary loops.

ISSN:1422-6405    

DOI:10.1159/000147999

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Satellite cells (SC) are present in all types of skeletal muscles. They can exhibit DNA replication and mitotic divisions throughout their life. Depending on the kind of muscle, a different number of SC is present. The aim of this study was to establish whether the differences in muscle metabolism are reflected in the quantitative ultrastructural evaluation of their SC. Two skeletal muscles of rats, soleus (SOL) with predominant slow fibers and extensor digitorum longus (EDL) with predominant fast ones, were studied. Morphometric analysis was performed according to the modified method of Weibel [Stereological Methods, vol 1: Practical Methods for Biological Morphometry. London, Academic Press, 1979]. In the SC of EDL mitochondria, rough endoplasmic reticulum and Golgi apparatus were less frequent as compared with the SOL. The volume fractions of these organelles were much higher in SC of SOL than in EDL. The ribosomes and polyribosomes were more densely packed in SC of SOL than in EDL. Ultrastructural morphometric evaluation demonstrated significant differences between the SC components of two different muscles: a slow (SOL) and a fast (EDL) one.

ISSN:1422-6405    

DOI:10.1159/000148000

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

This study is a part of a work to design a radiographical method to objectively define the conformation of an equine digit and to assess the individual appropriate trimming of a horse. Various angles were measured directly from the phaangeal bones. The authors observed that the bone relief of the sesamoid ligament insertions on the proximal phalanx was an essential landmark to determine the phalangeal alignment. The same angles were measured from specific radiographs and made it possible to quantify the rotation imposed to the proximal phalanx. The authors also noticed that the phalangeal rotation had little influence on the radiographic image of articular asymmetry.

ISSN:1422-6405    

DOI:10.1159/000148001

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In the present paper some aspects of the morphology of muscles in muscle groups are investigated modelwise. The analysis is initiated by the observation that the skeletal surfaces of the body are too small to provide the origin area for all muscles, and that therefore they must be enlarged by aponeuroses of muscular origin. These aponeuroses provide flexible surfaces of origin which allow to adapt the individual muscle shape to the various spaces available in the body, and to optimize their configuration in muscle groups. The shape of these origin surfaces determines the shape of the muscles and of their end tendons; this relationship is closely investigated. The models are illustrated by dissection examples of the muscle groups at the elbow, and may find an application in the teaching of clinical anatomy.

ISSN:1422-6405    

DOI:10.1159/000148002

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

In the carpal tunnel anatomical interconnections between the tendons of the musculus flexor digitorum profundus are systematically present. These interconnections limit the mutual tendon displacements, which decreases finger independence and may be problematic in a musician’s hand. The present study investigates a possible role of the synovial sheaths in the formation of these intertendinous connections in the carpal tunnel. To this end a morphological model is provided which correlates the often distinctly fibrous structure of the deep flexor tendons in the carpal tunnel and the frequent exchange of tendon fibres between the tendons to the different fingers, with the tendency of the synovial membranes to strongly adhere to the tendons. This model is validated by gross dissection results, and by cross sections of the flexor tendons in the carpal tunnel. In agreement with the model, the anatomic data show that the synovial membranes tend to invade and become trapped in tendons made up from individualised tendon strands, and also strongly adhere to the substantial amounts of tendon fibres which may be exchanged between the flexor tendons proximal to the lumbrical origins. These fibres and the synovial membranes may form a strong fabric able to withstand substantial stretching forces of interconnected oppositely pulled flexor tendon

ISSN:1422-6405    

DOI:10.1159/000148003

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

Up to now computerized interactive 3-dimensional (3D) atlases of human anatomy have been based on radiological data or artificial geometric models as spatial descriptions of morphological structures. Besides the obvious advantages of this data (e.g. already in digital format, geometrical correctness) the lack of high resolution anatomical slices of larger regions of the human body has prevented the use of more realistic anatomical data so far. Now, the Visible Human Project offers high quality anatomical slices of complete cadavers. Therefore, on the one hand, new opportunities for realistic virtual 3D models of anatomy are open. On the other hand, just the major advantages of the visible human data (e.g. realistic colors and textures, high resolution) result in new demands on the image processing and visualization techniques. This paper describes experience, solutions and results with a volume-based approach for building realistic anatomical 3D models.

ISSN:1422-6405    

DOI:10.1159/000148004

出版商:S. Karger AG    

年代:1997

数据来源: Karger

摘要:

An anomalous vein indicating the persistence of the hepatic segment of the infeior vena cava (left vena revehens) was found in a 60-year-old male cadaver. This vein emerging from the left lobe of the liver passed through the diaphragm at 3 cm leftward of the vena cava foramen and entered the coronary sinus at its termination, which in turn opened into the right atrium. A more detailed dissection of the liver showed that the ligamentum venosum originating from the left portal vein connected directly to the anomalous vein. No persistent left superior and inferior venae cavae were present. These results suggest that this persistency is not associated simply with the existence of the left venous system as stated previously, but is closely related to the formation of the ductus venosus.

ISSN:1422-6405    

DOI:10.1159/000148005

出版商:S. Karger AG    

年代:1997

数据来源: Karger