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| 2011 Audio [http://lectopia.telt.unsw.edu.au/lectopia/lectopia.lasso?ut=153&id=110471 Lecture 2 Audio]
| | ==2018== |
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| == Fertilization ==
| | Removed old links |
| {|
| | * JCB - Movie Collection [http://jcb.rupress.org/misc/annotatedvideo.shtml#Mitosis Mitosis] | [http://jcb.rupress.org/misc/annotatedvideo.shtml#Cytokinesis Cytokinesis] |
| | [[File:Mark_Hill.jpg|100px]] | | * '''2008''' ANAT3231 Lecture PDF lecture14-15 [http://cellbiology.med.unsw.edu.au/units/pdf/08L14-15s1.pdf 1 slide/page (view)] | [http://cellbiology.med.unsw.edu.au/units/pdf/08L14-15s4.pdf 4 slides/page (print)] | [http://cellbiology.med.unsw.edu.au/units/pdf/08L14-15s6.pdf 6 slides/page (print)] | [http://cellbiology.med.unsw.edu.au/units/pdf/08L14-15txt.pdf text (print)] |
| | Gamete formation, menstrual cycle and fertilization will be covered in detail in this week's Laboratory. The notes below are included for information purposes, we will not complete all content shown below within the lecture. | |
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| Fertilization is the complete process resulting in the fusion of haploid gametes, egg and sperm, to form the diploid zygote. The recent development of aided fertilization is described as in vitro fertilization (in vitro = "in glass", outside the body, IVF). Clinically, all these aided fertilization techniques are grouped as Assisted Reproductive Technologies or ART.
| | {{2017ANAT2341online-lectures}} |
| |}
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| ===Fertilization Preparation===
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| Prior to the fertilization process commencing both the gametes oocyte (egg) and spermatozoa (sperm) require completion of a number of biological processes.
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| * '''Oocyte Meiosis''' - completes Meiosis 1 and commences Meiosis 2 (arrests at Metaphase II).
| | ==2017== |
| * '''Spermatozoa Capacitation''' - following release (ejaculation) and mixing with other glandular secretions, activates motility and acrosome preparation.
| | Deleted these sections of lecture. |
| * '''Migration''' - both Oocyte and Spermatozoa.
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| ** oocyte ovulation and release with associated cells, from ovary into fimbria then into uterine tube (oviduct, uterine horn, fallopian tube) and epithelial cilia mediated movement.
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| ** spermatozoa ejaculation, deposited in vagina, movement of tail to "swim" in uterine secretions through cervix, uterine body and into uterine tube, have approximately 24-48h to fertilize oocyte.
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| [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=endocrin&part=A972&rendertype=box&id=A1230 Endocrinology - Diagram of the comparative anatomy of the male and female reproductive tracts]
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| ===Oogenesis===
| | '''Next''' |
| [[Oocyte_Development|Oocyte Development (Oogenesis)]]
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| [[Image:Ovary5x.gif|thumb|Histology of the Ovary]]
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| [[Image:Ova41he.jpg|thumb|Preantral Follicle]]
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| [[Image:ova20he.jpg|thumb|Antral Follicle and Oocyte]]
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| * Process of oogonia mature into oocytes (ova, ovum, egg) | | * [[ANAT2341_Lab_1|Lab 1 - Gametogenesis and Fertilisation]] |
| * all oogonia form primary oocytes before birth, therefore a maturation of preexisting cells in the female gonad, ovary
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| [[File:Human_ovary_non-growing_follicle_model.jpg|300px]] | |
| * humans usually only 1 ovum released every menstrual cycle (IVF- superovulation)
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| * oocyte and its surrounding cells = follicle
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| * primary -> secondary -> ovulation releases
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| Ovary- Histology - whole transverse section (cortex, medulla)
| | '''Homework''' |
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| ====Menstrual Cycle====
| | Beginning your online work - [[Help:Editing_Basics|Working Online in this course]] |
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| * Primary Oocyte - arrested at early Meiosis 1
| | # Make your own page. |
| ** diploid: 22 chromosome pairs + 1 pair X chromosomes (46, XX)
| | ## [[Special:UserLogin|'''Log-in''']] to the embryology website using your student ID and Zpass. |
| ** autosomes and sex chromosome
| | ## Click your <font color=red>'''student number'''</font> (shown in red at the top right of the screen following log-in) |
| | ## <font color=blue>'''Create'''</font> page using the tab at the top of the page, and save. |
| | # Add the following to the top of your page <nowiki>{{ANAT2341Student2016}}</nowiki> |
| | # How would you identify your [[Talk:Science_Student_Projects|Type in a group]] and add to your page. |
| | # What was the most interesting thing you learnt in today's lecture? |
| | If you have done the above correctly your ZID should be blue and not red on this page [[ANAT2341 2016 Students]]. |
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| * Oogenesis- pre-antral then antral follicle (Graafian follicle is mature antral follicle released)
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| * Secondary oocyte
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| ** 1 Day before ovulation completes (stim by LH) Meiosis 1
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| ** haploid: 22 chromosomes + 1 X chromosome (23, X)
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| ** nondisjunction- abnormal chromosome segregation
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| ** begins Meiosis 2 and arrests at metaphase
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| ** note no interphase replication of DNA, only fertilization will complete Meiosis 2
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| ====Ovulation (HPG Axis)====
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| [[Image:XXhpgaxis.gif|300px|HPG Axis]]
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| * Hypothalmus releases gonadotropin releasing hormone (GRH, luteinizing hormone–releasing hormone, LHRH) -> Pituitary releases follicle stimulating hormone (FSH) and lutenizing hormone (LH) -> ovary follicle development and ovulation.
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| ** release of the secondary oocyte and formation of corpus luteum
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| ** secondary oocyte encased in zona pellucida and corona radiata
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| * Ovulation associated with follicle rupture and ampulla movement.
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| ====Zona Pellucida==== | | ==2016== |
| [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=mboc4.figgrp.3722 MBoC - Figure 20-21. The zona pellucida] | | This topic will also be covered in this week's [[ANAT2341 Lab 1|Lab 1]] |
| * glycoprotein shell ZP1, ZP2, ZP3
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| * mechanical protection of egg
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| * involved in the fertilization process
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| * sperm binding
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| * adhesion of sperm to egg
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| * acrosome reaction
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| ** releases enzymes to locally breakdown
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| * block of polyspermy
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| ** altered to prevent more than 1 sperm penetrating
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| ** may also have a role in development of the blastocyst
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| ====Corona Radiata==== | | [[Media:Lecture 2016 - Fertilization - Embryology.pdf|Lecture - Print PDF]] |
| * granulosa cells and extracellular matrix
| | ==2014== |
| * protective and nutritional role for cells during transport
| | 2014 ECHO360 - [[File:ECHO360_icon.gif|right|link=https://lectures.unsw.edu.au/ess/portal/section/691ba9a0-7c35-4ad2-8fd0-846db7771557]] [[Lecture_-_Fertilization|Lecture 2]] - [https://lectures.unsw.edu.au/ess/echo/presentation/17e373fe-0138-40b1-b484-71959607af2a Rich Media Playback] | [https://lectures.unsw.edu.au/ess/echo/presentation/17e373fe-0138-40b1-b484-71959607af2a/media.m4v Vodcast Playback] | [https://lectures.unsw.edu.au/ess/echo/presentation/17e373fe-0138-40b1-b484-71959607af2a/media.mp3 Podcast Playback] |
| * cells are also lost during transport along oviduct
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| ===Gamete formation- Spermatogenesis===
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| [[Spermatozoa Development|Spermatozoa Development (Spermatogenesis)]]
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| * process of spermatagonia mature into spermatazoa (sperm)
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| * continuously throughout life occurs in the seminiferous tubules in the male gonad- testis (plural testes)
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| * at puberty spermatagonia activate and proliferate (mitosis)
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| * primary spermatocyte -> secondary spermatocyte-> spermatid->sperm
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| * Seminiferous Tubule is site of maturation involving meiosis and spermiogenesis
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| * Spermatogenesis- Meiosis | | 100,000,000,000,000 |
| * meiosis is reductive cell division | | * American - 100 trillion |
| ** 1 spermatagonia (diploid) 46, XY (also written 44+XY) = 4 sperm (haploid); 23, X 23, X 23, Y 23, Y
| | * English - 100 billion |
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| ====Spermiogenesis====
| | 10<sup>13</sup> |
| * morphological (shape) change from round spermatids to elongated sperm
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| * loose cytoplasm
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| * Transform golgi apparatus into acrosome (in head)
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| * Organize microtubules for motility (in tail, flagellum)
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| * Segregate mitochondria for energy (in tail)
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| ====Ejaculate====
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| * By volume <10 % sperm and accessory glands contribute majority of volume (60 % seminal vesicle, 10 % bulbourethral, 30 % prostate)
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| * 3.5 ml, 200-600 million sperm
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| * Capacitation is the removal of glycoprotein coat and seminal proteins and alteration of sperm mitochondria
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| * Infertility can be due to Oligospermia, Azoospermia, Immotile Cilia Syndrome
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| ** Oligospermia (Low Sperm Count) - less than 20 million sperm after 72 hour abstinence from sex
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| ** Azoospermia (Absent Sperm) - blockage of duct network
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| ** Immotile Cilia Syndrome - lack of sperm motility
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| ===Fertilization Site=== | | {| class="wikitable mw-collapsible mw-collapsed" |
| * Fertilization usually occurs in first 1/3 of oviduct
| | ! ECHO360 Recording |
| * Fertilization can also occur outside oviduct, associated with In Vitro Fertilization (IVF, GIFT, ZIFT...) and ectopic pregnancy
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| * The majority of fertilized eggs do not go on to form an embryo
| | | Link added after Lecture. |
| | [[File:ECHO360_icon.gif|right|link=https://lectures.unsw.edu.au/ess/portal/section/5157_00900]] |
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| Fertilization - Spermatozoa
| | Links only work with currently enrolled UNSW students. |
| * '''Sperm Binding''' - zona pellucida protein ZP3 acts as receptor for sperm
| | |} |
| * '''Acrosome Reaction''' - exyocytosis of acrosome contents (Calcium mediated) [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.3741 MBoC - Figure 20-31. The acrosome reaction that occurs when a mammalian sperm fertilizes an egg]
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| ** enzymes to digest the zona pellucida
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| ** exposes sperm surface proteins to bind ZP2
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| * '''Membrane Fusion''' - between sperm and egg, allows sperm nuclei passage into egg cytoplasm
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| Fertilization- Oocyte
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| * '''Membrane Depolarization''' - caused by sperm membrane fusion, primary block to polyspermy
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| * '''Cortical Reaction''' - IP3 pathway elevates intracellular Calcium, exocytosis of cortical granules [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.3743 MBoC - Figure 20-32. How the cortical reaction in a mouse egg is thought to prevent additional sperm from entering the egg]
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| ** enzyme alters ZP3 so it will no longer bind sperm plasma membrane
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| * '''Meiosis 2''' - completion of 2nd meiotic division
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| ** forms second polar body (a third polar body may be formed by meiotic division of the first polar body)
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| ====Formation of the Zygote====
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| [[Image:Early zygote.jpg|thumb|Early human zygote showing Pronuclei]]
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| * Pronuclei - Male and Female haploid nuclei approach each other and nuclear membranes break down
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| * chromosomal pairing, DNA replicates, first mitotic division
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| * Sperm contributes - centriole which organizes mitotic spindle
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| * Oocyte contributes - mitochondria (maternally inherited)
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| ====Sex Determination====
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| * based upon whether an X or Y carrying sperm has fertilized the egg, should be 1.0 sex ratio.
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| * actually 1.05, 105 males for every 100 females, some studies show more males 2+ days after ovulation.
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| * cell totipotent (equivalent to a stem cell, can form any tissue of the body)
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| '''Men - Y Chromosome'''
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| * Y Chromosome carries Sry gene, protein product activates pathway for male gonad (covered in genital development)
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| '''Women - X Chromosome'''
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| * Gene dosage, one X chromosome in each female embryo cell has to be inactivated
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| * process is apparently random and therefore 50% of cells have father's X, 50% have mother's X
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| * Note that because men only have 1 X chromosome, if abnormal, this leads to X-linked diseases more common in male that female where bothe X's need to be abnormal.
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