Initiated by Schleiden and Schwann (1838-1839) that all animals and plants are made up of cells and their products, and that growth and reproduction are fundamentally due to division of cells.
Minute granule, present in many resting cells, just outside the nuclear membrane. Doubles before mitosis, and at mitosis the two centioles move apart and form the poles of the spindl, and the centres of the asters when present. Centriole may also be connected to axial filaments of flagella and cilia, e.g. axial filament of sperm tail grows out from centriole.
According to Boveri the centrosome is a "cyclical reproducing organ"of the cell. It is composed of two structures calleds centrioles, plase at right angles to each other and sorrounded by dense pericentriolar material. Each centriole is made up of nine triplets of microtubles arranged in a pinwheel array. The centrosome divides during interphase to form the poles of the mitotic spindle, and after division segregates with the centrosomes to each of the doughter cells. In contrast, during oogenesis the centrosomes degenerate after meiosis, leaving the oocyte without a "division centre". This is than contributed by the sperm during fertilization.
Cylindrical posterior part of the uterus of mammals, which leads into the vagina. Contains numerous glands supplying mucus to vagina.
La chlamydia trachomatis è un batterio parassita che nella donna infetta la cervice, la ghiandola del Bartolino (dotto escretore posto sulle piccole labbra) e l'uretra. Se risale fino alle tube, causa malattie più gravi come la salpingite e la malattia infiammatoria pelvica. Nell'uomo causa uretrite e epididimite. Se infetta i vasi deferenti (vedi voce) e l'epididimo provoca una stenosi dei dotti (restringimento più o meno grave fino alla chiusura) e provoca oligo-azoospermia.
One of the two strands, which result from duplication of a chromosome, found during prophase and metaphase of mitosis or meiosis. They separate at anaphase and are then knows as daughter-chromosomes.
Temporary organ of internal secretion, of the hormone progesterone. Formed in mammals in interior of a ruptured Graafian follicle after ovulation, by ingrowth of follicle wall, which became yellow secretory luteal tissue. Formation occurs as a result of action of luteinizing hormoneof pituitary. If ovulation does not result in fertilization, then corpus luteum soon degenerates. If fertilization occurs, corpus luteum persists and continues secreting during part or all of pregnancy.
Special organelles originate as vescicles in the Golgi complex containing, amongst other substances, enzimes and mucopolysaccharidies. During egg activation, the granules break open releasing their contents into the perivitelline space (the gap between the oocyte plasma membrane and the vitelline coat). There are two immediate consequences of cortical granule exocytosis: the perivitelline space first increase in volume, and the vitelline coat in then trasformed into a thick, hard protective structure.
The mass of granulosa cells associated with the oocyte from the antral follicle stage until after fertilization. Cumulus cells contribute to the intrafollicular enviroment of the developing oocyte.
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