LeCturer : Maher Hadidi

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1 lecture # : 1 4 Date : Sybject : LeCturer : Maher Hadidi :t if, Done by:

3 Gametogenesis The process of germ cells formation (gametes) which, involves the chromosomes and cytoplasm of the gametes, to prepare them for fertilization. During gametogenesis, the number of chromosomes is reduced by 1 /2 and their shape of cells is changed. Spring 2013 Dr. Maher T. Hadidi, University of Jordan 24 1

4 Gametes / /?,Corona //radiala.--nudeus pel/ucida T Main parts of human sperm. ; Parts of human ovum with surroundtng layers The male gamete (sperm) and the female gamete (ovum) are highly specialized sex cells. Each contains 1 12 number of chromosomes (haploid ln cells) that reduced during Meiosis. Each carries a mixture of Paternal and Maternal genes. Fertilization results in a new cell, the Zygote, that have a mixture of genes from the parents (PM). Spring 2013 Dr. Maher T. Hadtdi, University of Jordan 25 2

6 Oogenesis-1 Transformation of Oogonia (primitive ovum) starting at 5th week of pregnancy into mature ovum at puberty. Ovarian Layers 1-4. Main function of ovary, to produce mature Ovum ready for fertilization. Occurs in the cortical regions of the Ovary 1-3, that contains Oocytes at various stages of development. Oogenesis is a repetitive monthly ovarian cycle during females reproauctive period (about 33 Years from puberty to menopause). Spring 2013 Dr. Maher T. Hadidi, University of Jordan 27 4

7 Oogenesis-2. iry Oac~fc <;:~wind.foii'ij: Cermina[ epttheuum t)oqoma 1 ""' I. 1.~ :1.., I \ "" ) :_;... rumca a~6ugwea". \?... 3 Ovanan Corttca[ 'i(ffjlon Begins about end of Swk,... - h d 1 M n r.ut!i -~i.:-..,-.. W en P nmor Ia germ, Ovarian... ". ~ aw. 41 Wl~/~ntrum. - ~~~~Yafhi~~ ~~ed~;~~oping "'~~:~ 1.. ~-Jry Oocyte ~~~~~"m'' multiple mitosis and ~- (-'{-'---'----/ -/--IiJiptureJil,!ldt transform into Oogonia. ~. " ~~ By end of 3rd Month:,. /~r..'..._._' _... l r.. -Coronaradiat:J Oogonia multiply by..1 \ - 2 ')'0oqte mitosis then enlarge to :Bfooadot ~ ry Oocytes that surrounded by flat epithelial cells called 0 primordial follicle Ql. == == ==== ~ ' / ogoma Mitosis continues... Primordial ';,:};1 follicle :!~:JL_Fiat follicular cell Spring 2013 Dr. Maher T. Hadidi, University of Jordan 28

8 Oogenesis-3 II By SM: Number of lry Oocytes reach.. about 7 million. By 7M: Most degenerated except few enlarged as lry Oocytes, all entered Prophase Meiosis I and arrested there. At birth: All lry Oocytes completed Prophase Meiosis I then arrested in Diplotene stage u_;.s...ji J_,b until puberty. ~ At that time, their number is about 2 million but most degenerates during childhood and only tv40,000 remain until puberty. Spring 2013 Dr. Maher T. Hadid1, University of Jordan 29 6

9 At puberty: In each ovarian cycle, only one lry Oocyte reach maturity and ovulated. ~ Only tv 400 lry Oocytes will be ovulated during female fertile life (tv =33 years). Oogenesis-3 Spring 2013 Dr. Maher T. Hadidt, University of Jordan 30 7

10 Oogenesis- 4 Preovulation: lry Oocyte. complete Meiosis I then transformed into 2ry Oocyte. At Ovulation: 2ry Oocyte r expelled out the ovary at Day 14 of the female reproductive cycle under influence of LH hormone with covering layers..... Ovulated ovum enter t"0. _.... > uterine tube in anticip~tion~ to be fertilized and stay viable only rv 24 hours. Ovulated ovum aiming to reach the endometrium while it is in the secretory phase.. Jry Ooc'!te ~ :ou'irwj 0!{i& qermitta[ epitlieaum Ooqoru<l - ~ I 'L- rr:. rr:. ' :! \ "" ~-- 3 _/1untca aw11gtnea I j. \ /...)..- 3 _Ot:anan Cortica{'R.,iJic'lt '..., '- c::orona radia.ta Nucleus Zona pel Iucida i I I I I Spring 2013 Dr. Maher T. Hadidi, University of Jordan 31

11 - -- D & t II'"" Oogonia ~ unng,e a l,e a~ Primordial,.;.'-~ is formed,~ follicle.:{ ->-;;--CTof ovary consists 1ry Oocyte+ unilayer of flat cells ~'::r -~-Fiat f~llicular_ cell 111,..,:; At Puberty: A small group of primordial Growing _ --- "~--- Cuba1dal folhcular cell follicles begins daily process of 1ry follicle i ' follicular growth: //... / Zona pellucida farming 1- Modiftcations of Oocyte 2- Modifications of Granulosa cells by mitosis from flat cells /om/./. _., ' /"/ ultllammar _ "~=:-~ mature 1 ry.),'::~~ l --~~~~~:re..-' '''"4 : Single Cuboidal Layer/ _.. Zona pellucida ", Granulosa cells P -Theca intema J/ t Multilayer granulosa cells,/ Antral ' --~;_--Antrum '<.. l' follicle :" _Theca interna Small fluid-spaces formed Between '. granulosa cells l -- i-- Theca extern a,_unite- Antrum Joo+ 2ry follicle_ "-... "'"''... Mature (Graafian) foll~le' Ill"" During reorganization of granulosa cells, some cells concentrate at follicular wah»-+cumulus Oophorus (~i ~_;). Granulosa ceils ' ''""'"'~"c'';'n ~-theca ~xterna -Theca tnte rna ---Antrum --Granulosa cells - Corona radiata ~--Cumulus oophorus Another group of cells concentrate around Oocyte ~ Corona Radiata that accompany the Oocyte when leaving the Ovary. 9

Gametogenesis. Omne vivum ex ovo All living things come from eggs.

Gametogenesis. Omne vivum ex ovo All living things come from eggs. Omne vivum ex ovo All living things come from eggs. William Harvery, 1651 Gametogenesis This lecture is the preface, so to speak, to embryology; that is, it introduces the development of the specialized