Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Oogenesis in Mammals
In mammals also the oogonial cells are derived from primordial germ cells. The multiplication phase, that is all of the oogonial divisions and transformation of oogonia into oocyte are completed either before or shortly after birth. A number of oocytes are produced, all of which are held in meiotic arrest in prophase I.
Essentially in mammals the period of oogenesis covers the entire life of an individual from birth to ovulation. The meiotic arrest is released at the time of puberty after which a group of oocytes begin development during each cycle. A large percentage of oocytes fail to undergo maturation and therefore degenerate. The oocytes in mammals are found in close association with non-germ cells in the ovary. The non-germ cells or the accessory cells produce steroid hormones, transport some of the essential cytoplasmic components into the oocyte and are also involved in the formation of cellular or non-cellular layers that surround the fully differentiated egg. The accessory cells that surround the egg are of two types -
(1) Follicle cells,
(2) Nurse cells.
The follicle cells are somatic cells which surround the oocyte as a single layer of the cells and are known as follicular epithelial cells. The nurse cells are derived from germ cell line and are connected with the oocyte by cytoplasmic bridges. During the growth of the oocyte, the single layered follicular epithelium proliferates and becomes multilayered and the cells are called granulosa cells. The granulosa cells and the oocyte are separated by a space which is filled with sulphated glycoproteins. This layer becomes the zona pellucida of the oocyte. When proliferation of the granulosa cells is completed they secrete a fluid that accumulates in the intercellular spaces. The fluid filled spaces coalesce to form a cavity called antrum.
Osteomalacia Similar to rickets in young growing animals, osteomalacia is a disease of mature animals caused by absolute or relative deficiency of any one or combination of cal
how to make question on classification of Protozoan parasite
Connect point A and D by line which is convex to the left. The left border is formed by the left ventricle except at its upper end which is formed by the left auricle where there i
Q. Is the cell division happening during the entire cell cycle? What is the interphase? Cell division properly occurs throughout the mitotic phase of the cell cycle. During int
Starting from a ribosome in the cytosol, list in sequential order the organelles and cellular components a secreted protein would encounter from translation to secretion.
what are the main coponents of human skeleton?
What is mutualism? Mutualism is the ecological interaction in which both participants advantage and that is obligatory for their survival. Mutualism is a harmonious (positive)
Explain the Competitive behaviour of social animal group dominance behaviours removal of individuals to other groups which minimises inbreeding eg lions, apes.
Etiology -Although this approach less desirable, it is useful, short-term option if the etiology of the condition remains unknown. - The patient must inform about what will
Drawbacks of Lamellar model This model does not explain the elasticity of PM. Although this model says that PM is elastic but it also states that head of lipid molecules is
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd