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.
1. The genes for ruby eyes (rb), tan body (t) and cut wings (ct) are all found on the X-chromosome of Drosophila melanogaster. All of these are recessive traits. They map in the or
Q. Illustrate Hypertrophic cardiomyopathy? It is a genetic disorder due to mutations in the gene that encodes for β-Cardiac myosin heavy chain (Localised to chromosome 14). It
A fruit fly has four pairs of chromosomes in its cells. At meiosis, how many different combinations of maternal and paternal chromosomes are possible in the gametes?
Pocket Psedocyst : lesions present as endodontic origins from canals . It makes lumens resemble granuloma . All lesions lined until root canal or apical foramen communicat
BLOOD - Blood is a mobile connective tissue composed of a fluid, the plasma and the cells, the blood corpuscles. Blood is basis of life. Blood is the softest tissues
What is the substance that stimulates the production of red blood cells? Which is the organ that secretes it? Under what conditions does this secretion increase? The substance
Enumerate about the Baule unit A mathematician from Gottingen by the name of B. Baule assisted Mitscherlich with his calculations. The quantity of any growth factor (nutrient
CHROMOSOME S AND MOLECULAR HOMOLOGY - The DNA content of diploid cells is similar. Hoyer et al in 1965 showed that DNA of humans was 100% similar with chimpanzee and 94%
MALE REPRODUCTIVE DISORDERS Generally, about 5-10% of cattle bulls reaching sexual maturity would be suffering from poor reproductive efficiency or sterility. Crossbreeding ha
evolutionary effect of Oracle clinical applications in Pharmaceutical industries
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