Biology Is Love

Mechanism of Release Of Ovum (OVULATION) - Souti Das  During the 1st 5 months of development, a finite number of primordial follicles form in the fetal ovary, these follicles contain an oocyte surrounded by follicular cells. These primordial follicles arrests at 1st meiotic division till puberty and then they further undergo development and become primary follicles.                                       During the early primary follicular stage, follicular cells are cuboidal and Zona Pellucida appears as a thin band of glycoprotein that separates oocyte and follicular cells. In the late follicular stage, follicular cells proliferate into a stratified epithelium known as Zona Granulosa . During the secondary follicular stage, proteoglycan riched antrum appears in the Grannulosa layer. Cell layers in the Zona Grannulosa increase and thereby Zona Pellucida gets thickened. In this sta...

Fertilization In Sea Urchin - Malay Nayak 1.        What is sea urchin? ·          Spiny water animal ·          Phylum ECHINODERMATA ·          Roughly spherical sea animal Sea Urchin   2. Why Sea Urchin ? The cell-surface events that take place during fertilization have been studied most extensively in sea urchins, members of the phylum Echinodermata . ·    Sea urchin gametes are easy to collect, ·    fertilization occurs outside the animal body. ·    As a result, researchers can observe fertilization and subsequent development simply by combining eggs and sperm in seawater in the laboratory.