摘要:

AbstractThe changes in the levels of blood sugar and plasma cholesterol and the histology of the pancreatic islets were studied following hypophysectomy in the snake,Natrix piscator.Hypophysectomy inN. piscatorproduced a progressive decrease in glycemia and after 15 days, an aglycemic condition developed accompanied by slight degranulatory changes in the alpha cells of the pancreatic islet tissue. A significant decrease in the muscle glycogen concentration was also noticed 15 days after the operation. Atrophic changes were evident in the thyroid and adrenal glands of the operated animals.An extract of three pituitaries when injected in a normal snake did not produce any change in the blood sugar level. It is suggested that the absence of a diabetogenic action following injection of pituitary extract may be due to the opposing action of the endogenously produced insulin in the intact pancreas of the animal.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe morphology of the stomodeal nervous system of the adult dragon fliesBradinopyga geminataandOrthetrum chrysisis described.No gastric ganglion or ganglion ingluviale has been found. Instead the oesophageal nerve forks near the junction of the proventriculus and the midgut. The two nerves run on either side of the midline as ingluvial nerves and enter the proventricular ganglionic masses. These ganglionic masses are connected by a transverse nerve, which has been called as the nervus transversus proventriculare.Both bipolar and multipolar types of sensory cells have been found over the surface of the crop. These cell bodies appear to be interconnected by connective tissue. Dendrites of these cells terminate on the longitudinal muscle fibres, surrounding the proventriculus and the midgut. The proximal processes of these cells enter the proventricular ganglionic mass. In methylene blue whole mounts they resemble the stretch receptors, hence it is quite probable that they play some role in the peristaltic movement of the gut.The corpora cardiaca lie dorsal to the pharynx and are connected to the brain by two pairs of nerves, the nervi corporis cardiaci (NCC I, NCC II). Unlike in other insects, the nerve connecting the corpora cardiaca with the corpora allata is slender and arises as a branch of the nerve, nervus corporis allati II.The corpora alata are spherical to ovoid in shape and lie ventral to the nerve cord. Anteriorly they are attached to the inner wall of the hypopharynx and posteriorly to the subesophageal ganglion by a pair of nerves, the nervi corporis allati II.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe hypothalamo‐neurohypophysial complex ofAilia coilais well demonstrated with the help ofin situstaining procedure. Both pars magnocellularis and pars parvocellularis components of the nucleus preopticus contribute to the formation of the right and the left main neurosecretory tracts. Anterior one third of these tracts are loosely set and posteriorly they became more compact. From the posterior two thirds of the main tracts several pairs of lateral tracts were given off which join at the midline to form the paired median tracts. The median and the main tracts jointly enter the pituitary as the common tract. The common tract on entering the pituitary often divides into two or more branches and enter the pars intermedia independently.The rostral pars distalis is least innervated by the neurosecretory axons. Since the proximal pars distalis has varying amount of AF‐positive cells, and the pars intermedia has the bulk of the neurosecretory axons both these regions are stained dark in thein situpreparations. Bulk preparations provide a clear topographic picture of the entire neurosecretory system, which is very difficult to visualise in tissue sections and in their reconstructi

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe motility of greatly swollen, immobile bull spermatozoa is restored by cellular dehydration caused by (a) an increase in the medium tonicity or (b) an experimentally induced decrease in the intracellular content of osmotically active particles. The coiled motor apparatus will then gradually uncoil, exhibit kinetic activity and finally take on a straight configuration analogous to that of spermatozoa in isotonic media.The coiling of the motor apparatus occurring in swelling spermatozoa and its uncoiling in swollen spermatozoa subjected to dehydration are processes evoked by the pressure exerted on the motor apparatus by the shape‐altering cell membrane and are not dependent on the presence of any movements in the motor apparatus. Thus, these processes occur in fluoride‐immobilized spermatozoa. The uncoiling process is, however, gradually inhibited and finally blocked by storing the spermatozoa previously in a hypotonic medium for a prolonged period. In this case, subsequent cellular dehydration will induce lysis of the cells and their motor apparatus will remain coiled inside the leaky membrane envelope. The background to this fact is discus

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00571.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe formation of the micropyle inTilapia mossambicaandStigmatogobius javanicus, two fresh water teleosts is described. InT. mossambicathe micropyle is formed by a single modified follicular cell, while inS. javanicusit is formed by a cellular mass derived from the follicle.

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00572.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe accessory olfactory organ ofLampetra fluviatiliswas found to consist of clusters of interconnected vesicles in tenuous connection with the exterior medium via the cavity of the olfactory organ. The walls of the vesicles are composed of two types of cells. One type are primary sense cells that resemble the olfactory sense cells in that their nucleus is situated peripherally and their axons pass directly into the brain. They differ from the olfactory sense cells in the size and number of cilia they bear, and also in the internal structure of the cilia. The second cell type are supporting and/or secretory cells. It is concluded that this sense organ is capable of responding to a “special kind” of chemical stimulus and its possible function is discus

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00573.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractDuring oogenesis in Pentastomida the oocytes wander from a germinal zone in the mid‐dorsal ovarial wall to the lateral pouches of the ovary. The growth phases are initiated during that migration, but not until the lateral pouches are reached does the oocyte grow considerably. A Balbiani body consisting of numerous mitochondria, and various vacuolar inclusions are formed, and at the same time the oocyte bulges out into the hemocoel. Some wall cells form a stalk and cover part of the oocyte towards the hemocoel. During later stages of oocyte growth they withdraw, and the oocyte is separated from the hemocoel only by an extremely thin basement membrane. It seems that the young oocytes obtain nourishment from the ovarial lumen by way of the wall cells. The contents of the lumen in its turn seems to be derived from the hemocoel through the activity of mid‐ventral secretory cells. The older oocytes are provided with numerous microvilli, and material for the growth of the oocytes must be taken up directly from the hemocoel. A very dense egg shell is secreted by the oocyte. In nearly mature oocytes the microvilli withdraw from penetrating this shell, and a mucopolysaccharide layer is formed beneath the shell. The mature oocytes in some unknown way make their way to the ovarial lumen whence they are transported to the ute

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00574.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe morphology of the parietal shield of the Carboniferous osteolepiformMegalichthys laticepsis described. Of special note are the following features, none of which have hitherto been observed in other members of the group: each intertemporal section of the lateral‐line canal system gives off a large, backwardly directed tube which enters the posterior part of the ipsilateral parietal bone where it becomes highly ramified; anterolaterally each intertemporal bone possesses an irregularly shaped and forwardly directed projection—the frontodermosphenotic process—which is traversed by the intertemporal section of the lateral‐line canal system. In addition, evidence is offered thatMegalichthys laticepswas equipped with a paired extratemporal bone as well as a tripartite extra‐scapular series of exoskeletal elements; also, that the presence of the extratemporal bone most likely was correlated with the configuration of the subjacent part of the endocranium; and, finally, that no appreciable movement occurred between the anterior and posterior cranial

ISSN:0001-7272    

DOI:10.1111/j.1463-6395.1972.tb00575.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY