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Home , Cleavage (embryo), Oogamy

[DOCUMENT TITLE]

FERTILIZATION, CLEVEAGE AND IMPLANTATION

1Lusia Hayati

1Department of , Faculty of Medicine, University of Sriwijaya

Email : [email protected]

Abstract

Most of the livestock in Indonesia are still conventional or traditional farms, where the quality of the seeds, the use of technology and the skills of farmers are still relatively low, thus affecting the productivity and genetic quality of livestock. Therefore it is necessary to have knowledge about livestock reproduction that discusses fertilization, cleveage and implantation. Fertilization or fertilization (singami) is the fusion of two which can be a nucleus or nucleus cells to form a single () or fusion of the nucleus. the process starts with the preparation of ovum cells and spermatozoa; penetration; core incorporation; and early zygote cleavage. Fertilization phase is the meeting between cells and ovum cells and will produce zygote. Zygote will perform (cleavage). The zygote then undergoes growth and development through stages, namely division, , and . Implantation or also known as oxidation is the process of implanting the , which is the result of conception, into the uterine wall (endometrium) to further develop.

Keyword : fertilization, cleveage, implantation, reproduction

138 Fertilization or fertilization (singami) 1. Introduction is the fusion of two gametes which can Low productivity and genetic quality of be a nucleus or nucleus cells to form a livestock is still a problem in the world of single cell (zygote) or fusion of the livestock in Indonesia. This situation occurs nucleus. Usually involves the fusion of because most of the livestock in Indonesia the (plasmogamy) and the are still conventional or traditional farms, fusion of nuclear material (karyogamy). where the quality of the seeds, the use of With meiosis, the zygote forms a technology and skills of farmers are still fundamental feature of most eukaryotic relatively low, livestock raising is done on an sexual cycles, and basically the fused occasional basis (not a major economic gametgamete is haploid. When both are source) with 1-3 livestock ownership. motile as in plants, then fertilization is Reproduction is a physiological process in called , if they differ in size but living things to produce offspring. Higher are similar in shape it is called reproduce sexually and the , if one is not motile (and reproduction process includes several usually larger) it is called oogamy. This is physiological levels that include very typical of some plants, animals, and complex functions and are integrated most fungi. In some gymnophytes and between one process and another. These all antophytes, the gametes are not physiological levels include the formation of flagellated, and the pollen tube is cells (gametes), release of functionally involved in the fertilization process. differentiated cells, mating to bring together male and gametes, 2. Types of Fertilization fertilization, fusion between the two 1. (typical in pronuclei, growth, differentiation and aquatic animals): the gametes are development of the zygote until birth. removed from the body before Normal. The field of livestock productivity fertilization cannot be separated from the reproductive 2. (typical for process. Reproductive success is a reflection adaptation to life on land): sperm of the success of a livestock business. are inserted into the female Population development is highly dependent reproductive area which is then on broodstock and quality seedlings as well followed by fertilization. After as the large number of cows born. This is of fertilization, the forms a course highly supported by optimal fertilization membrane to prevent reproductive management. Production and further sperm entry. Sometimes the reproduction are closely related to the sperm is needed only to activate the development and availability of livestock. egg (Anonymous, 2008) Failure of a livestock to become pregnant in one or more matings will eliminate the 3. Fertilization process product of conception in one or more Fertilization occurs when gestation periods. spermatozoa cells are released and can Based on the description above, it is fertilize the ovum in the ampulla of the necessary to have knowledge about the fallopian tube. As many as 300 million science of livestock reproduction, especially spermatozoa are ejaculated into the discussing the issue of fertilization, cleaveage female genital tract. About 1 million can and implantation to help improve the swim through the cervix, hundreds of genetic quality of an . which can reach the fallopian tube and only 1 can fertilize an egg. Spermatozoa 2. DISCUSSION cells have a life span of about 48 hours (Cambridge, 1998). Before fertilizing an 2.1 FERTILIZATION egg, spermatozoa must go through the 1. Definition of fertilization

139 capacitation and acrosome correction division occurs in prokaryotic cells stages first. Capacitation is a period of such as bacteria. The purpose of this adjustment in the female reproductive division is to form new offspring. tract, lasting about 7 hours. During that b. Mitotic Cell Division time a glycoprotein sheath from the Mitotic division, division which cement plasma is removed from the results in two daughter cells that are plasma membrane which encloses the the same as the parent, meaning that acrosome region of the spermatozoa. these daughter cells can divide again. Meanwhile, the acrosome reaction In Humans, this division occurs in occurs after the attachment of somatic meristem cells (young body spermatozoa to the zona pellucida. This cells). This process takes place reaction causes the release of enzymes through structured and orderly needed to penetrate the zona pellucida stages, unlike Amitosis which occurs contained in the acrosome (Sadler, spontaneously. 1996). (ovum) will reach the tube more than one hour after This mitotic division goes through . The ovum is surrounded by two stages, namely Kariokinesis and the corona of small cells and the zona . pellucida which will filter the existing 1. Kariokinesis spermatozoa cells so that only one cell This process shows a striking can penetrate the ovum. difference in each phase and aims to After the spermatozoa penetrates divide the core material, as for the the ovum, it combines its core material changes as follows: and stores the usual double  Interphase chromosome complement. This At this stage the cells do not chromosome contains all the genetic divide. The nucleus consists of information which will be passed on to ribosomal RNA and is the site of the offspring (Canbridge, 1998). protein synthesis and dark matter The fertilized egg will form a zygote known as chromatin or the form of which continues to divide by chromosome strings so that the into two, four, eight, sixteen and so on. shape of the chromosomes cannot be seen clearly. At one end of the cell, 2.2 Cleveage there are 2 pairs of proteins called 1. Definition of Cell Division centrioles, but in plants, centriosoles Cell division is the process of dividing do not appear. a parent cell into two or more daughter  Prophase cells. Cell division is usually a cycle of At this stage the DNA begins to be small cells which will lead to the next packaged into chromosomes. The major cycle. chromosomes begin to shorten and 2. Types of cell division and their thicken. In animal cells the centrioles processes divide and each move to the opposite a. Amitotic cell division (binary fission) pole and a spindle thread is formed Amitotic cell division is also called which is connected to the poles. direct cell division or does not go Eventually the chromosome appears through certain stages, this process to consist of two chromatids also takes place spontaneously, or is attached to the centromere. The called binary fission. This process nucleolus is lost and the nuclear does not involve chromosomes why membrane is destroyed. is that? Because the DNA is present . Metaphase in such a small amount and size that In this phase, the chromosomes it cannot be packaged, most of this move into a line called the equator.

140 In addition, threads called spindles Interphase appear and are attached to the At interphase, the cell is in the centromere of each chromosome. preparatory stage for division. This spindle connects the The preparation is the DNA chromosomes to the 2 opposite poles doubling of one copy into two of the centricoles copies (the same as in the . Anaphase mitotic interphase). The final Each centromere that binds the stage of interphase is the chromatid divides together and the presence of two DNA copies that chromatid moves towards the are ready to be packed into cleavage pole, producing paired chromosomes copies of the chromosomes. - Prophase 1. At this stage the . Telophase following process occurs At this stage the chromosomes - Leptotene is the stage where the begin to organize to form a separate chromatin threads turn into nucleus and are surrounded by chromosomes. This is done by members of the nucleus. Cleavage self-compacting. Burrow / groove division narrows and - Zygotene / Zigonema, at this over time divides cells. In contrast, in stage, homolong chromatids pair plants, cleavage occurs with a cell up or synapses to form bivalents. plate rather than a cleavage burrow. The splits into 2 centrioles and moves to the 2. Cytokinesis opposite pole. During cytokinesis, the cytoplasm - Pakiten / Pakinema, the of animal cells is divided into two by chromosomes are then the formation of a contractile ring duplicated into 4 at this stage formed by and myosin in the and are called tetrads center of the cell. This contractile (homologous chromosomes that ring causes the formation of a multiply so that there are 4 cleavage groove which will eventually paired chromatids). At this stage, produce two daughter cells. Each of gene recombination often occurs these daughter cells that form through the cross-transfer contains a , along with process. cell organelles. In plants, cytokinesis - Diplotently, homologous is characterized by the formation of a chromosomes that were bivalent dividing wall in the middle of the cell. are separated. When there is This cytokinesis stage is usually cross movement, there will be a included in the telophase stage. chiasma as a sign. - Diakinesis, in the diacinesis c. Meiosis Cell Division phase, the nucleolus (nuclear This division will produce gametes membrane) will disappear and that cannot divide again until the the centrioles move to each pole fertilization stage. Meiotic division and form spindle threads. produces children who have half the - Metaphase 1. Homologous number of chromosomes that their chromosome pairs arrange parents have, occur in the themselves and face each other reproductive organs and directly at the equator. Half of the between phase 1 followed by phase 2 homologous chromosome pairs without interphase interrupted. The point towards the other pole and stages are as follows: the other half of the homologous a. Meiosis I chromosome pairs point toward

141 the other pole - Telophase II. In telophase II, the - Anaphase 1. Each homologous chromatids (or nowadays called chromosome begins to be pulled chromosomes) have reached the by the spindle thread to the poles of division. The total result opposite direction of the of this stage is that four cores cleavage pole. are formed. Each nucleus - Telophase 1. The chromosome contains half a pair of which still consists of two chromosomes (haploid) and one chromatids is at the poles. DNA copy (1n, 1c). Cytokenesis Furthermore, the nucleus II. There is cytokinesis II, each membrane is formed which is nucleus begins to be separated followed by the cytokinesis by a cell divider and eventually process. At the end of telophase produces four haploid twin cells. I two daughter cells are formed. Each daughter cell contains n 3. CLEAVEAGE (zygote cell division) chromosomes so that at the end Fertilization phase is the meeting of meiosis I two haploid between sperm cells and ovum cells daughter cells are formed. and will produce zygote. Zygote will - Cytokinesis 1. In cytokinesis I, perform cell division (cleavage). The each homologous chromosome zygote then undergoes growth and is separated by a divider so that development through stages, namely cytokinesis produces two cells, division, gastrulation, and each containing a chromosome organogenesis. with its twin chromatids Cleavage is the rapid cleavage of the zygote into smaller units called b. Meiosis II . The cleavage stage is a - Prophase II. In prophase II, twin series of mitosis that takes place in chromatids are still attached to succession immediately after each chromosome centromere. fertilization to produce and This stage sometimes occurs in a blastomeres short time because it is followed The initial process of embryo by the next stage. division in humans takes place along - Metaphase II. In metaphase II with the attachments of the embryo each chromosome (which to the uterine wall of its mother. contains two chromatids) Human in general do not have a stretches out in the equatorial , are fertilized by the egg as they plane. Spindle threads are move towards the uterus and the formed, one end is attached to initial divisions last less than 24 the centromere, and the other hours. The cleavage is meridional not end extends towards the poles of equal. Subsequent division is division in the opposite somewhat irregular, but quickly direction. forms a dense sphere of cells, called - Anaphase II. In anaphase II the the morulla. spindle thread begins to attract The zygote divides repeatedly the chromatids towards the until it consists of dozens of tiny cells, opposite poles of the cleavage. which are called blastomeres. This As a result, the chromosomes division can cover all parts, it can also separate their two chromatids be only in a small part of the zygote. and move towards different This division occurs by mitosis, poles. The separated chromatids although sometimes it is also are now called chromosomes. followed by continuous nuclear

142 division without cytoplasm. The area early gestation but is quite decisive at 105 of division traveled by the direction days of gestation (Fenton et al., Cited in of division when the zygote Toelihere, 1993). undergoes continuous mitosis into many cells, is called the division a. Stages of cell division plane. There are 4 types of division, 1. Stage Morulla namely: Morulla is a spherical (round) cell - Meridians, passing through the formation due to continuous cell animal and vegetal polar axis. division. Morula is a cell division that - Vertically, passing upright from occurs after the cells number 32 cells animal to vegetal poles does not and ends when the cell has produced a pass through aimal and vegetal number of blastomeres of the same poles. size but smaller in size. These cells - Equator, perpendicular to the axis condense to become small blastodic of the animal-vegetal pole and forming two layers of cells. At this time halfway between the two poles. the cell sizes began to vary. The cell - Latitudinal, parallel to the divides transversely and begins to equatorial plane. form a second layer of faintness at the anima cap. The morula stage ends According to Orphans (1990: 155) in when cell division has produced humans, division occurs holobastically blastomeres. The blastomer then irregularly. Where the plane and time of the condenses into small blastodisc to cleavage stages are not the same and are not form two layers of cells. simultaneously in various zygote regions. At the end of the division, two Initially the zygote divides into 2 cells, then groups of cells will be produced. The occurs at the 3 cell level, then the 4 cell level, first is the main cell group then the 5 cell, 6 cell, 7 cell, 8 cell level, and (), which includes formatic continuously until a balstomer is formed cells or inner mass cells, whose consisting of 60-70 cells, in the form of function is to form the body of the massive clumps called morula. embryo. The second is the In animals, the first and second division complement cell group, which includes of the fertilized occurs while the ovary , periblast, and auxilliary is in the fallopian tube. Normally, the cells. Its function is to protect and embryo is at the 4-cell stage of its contact the embryo with the parent or development when it enters the uterus. The the wider environment. embryoembryo is not immediately The tropoblast is attached to the distributed throughout the uterus but is uterine wall. The cells multiply rapidly temporarily held in the anterior part of the and enter the uterine epithelium in uterine cornua. Cleavage had reached the the early stages of implantation. After level of morula on day 5 to day 6 after the 9 days, all are retained in initiation of estrus and formation the uterine wall. When this takes with removal of the zona pellucida occurred place, the cells that are at the bottom on day 6 to day 8. Blastocyst elongation of the cell mass organize themselves occurs prior to implantation. After into a layer called the primary lengthening, the embryo is evenly which will form the distributed within the uterine horn. The digestive tract of food. The remaining length of the uterus increases rapidly from cells from the form a day 2 to day 6 after the onset of estrus. A chip, namely the embryo piece. linear weight gain of the uterus occurs Between the embryo and the during pregnancy. The space available in the tropoblast that covers the emergence uterus affects the number of children at of a cavity (amnionic cavity) containing

143 a solution. The cavity wall, namely the (endoderm). So gastrulation is the amnion, spreads around the embryo process of forming three embryonic and is surrounded by a cushion of layers. In further development the amniotic fluid. embryonic layer will experience growth and development to produce 2. Blastula Stage various organs of the body. is a process that The three layers produced by produces blastula, which is a mixture gastrulation are embryonic tissue of blastoderm cells that form a fluid- known as the , endoderm filled cavity as a . At the end and which are collectively of blastulation, blastoderm cells will referred to as the embryonic germ consist of neural, epidermal, tissue. The ectoderm forms the outer notochordal, mesodermal, and layer of the gastrula, the endoderm endodermal which will form organs. It lines the digestive tract of the embryo is characterized by two very distinct and the mesoderm fills as the space layers of flat cells forming the between the ectoderm and endoderm. blastocoel and the blastodisc is in the Eventually, these three layers develop transplanted vegetal hole covering into adult body parts. For example, the most of the yolk. In the blastula there human nervous lining comes from the are already differentiated areas to ectoderm, the outermost layer of our form certain organs such as digestive digestive tract and its organs come tract cells, exoderm nerve notochords, from the endoderm and most other ectoderm, mesoderm, and endoderm. organs and tissues, such as the In humans, the cleavage results in kidneys, heart and muscles, come from the form of a solid ball (morulla). The the mesoderm. outer layer of the blastula forms a layer surrounding the actual embryo, 2.3 IMPLANTATION while the embryo is formed from the 1. Definition of Implantation morulla (inner cells mass) / outer layer Implantation or also known as (tropoblast) on one side of the mass. oxidation is the process of implanting an cells in detach themselves, forming a embryo which is the result of shape similar to a blastula and this conception into the uterine wall structure is known as a blastocyst. The (endometrium) for further embryo attaches and stays on the development. Implantation usually uterine wall for a certain period of occurs on the 5th to 8th day of embryo time, where the embryo will get food development. And as for the sequence until it is born of events in the cell division in question is as follows: 3. Gastrula Stadium Prior to implantation, the zona Gastrula is an advanced formation pellucida disappears by way of lysis. of the blastula whose curvature is Prior to implantation, the blastosul fluid more pronounced and has a layer of contained a lot of potassium and the embryo's body wall and body bicarbonate ions. This material comes cavity. Gastrula in certain animals, from uterine fluids. After implantation, such as lower animals and higher the amount of potassium and animals, differ in the number of layers bicarbonate decreases, so that it is the of the embryo body wall. Triploblastic same as the level in the main serum. is an animal that has 3 layers of the embryo's body wall, namely the outer 2. Implantation Process layer (ectoderm), the middle layer The implantation process occurs after (mesoderm), and the inner layer going through the fertilization process

144 and the claveage process. Just when in embryo's invasion of the parent tissue, the form of a morula (undergoing trophoblast cells then differentiate into division into 32 cells), the embryo 2 types of cells, namely: begins to enter the uterus. The division 1. Syncytiotrophoblast cells are large, process is still happening. When going multinuclear cells that develop from through implantation, the embryo is a the cytotrophoblast layer. These blastocyst. cells actively secrete placental Pertama, zona pellucida akan hormones and transfer nutrients terlepas sebagai aktivitas dari enzim from the mother to the fetus. proteolitik dari airan uterus disebut 2. A group of cytotroblasts that are proses hatching. Lalu bagian dari invasive, pass through the blastosit, yaitu tropoblast akan endometrial stroma to reach the menempel pada endometrium dan main blood vessels, including the berkembang menjadi plasenta yang endometrial spiral artery. berfungsi sebagai penyuplai zat-zat makanan kepada fetus. In pigs, junction complexes begin to When in contact with the form between the tropoblast and the endomtherium, the tropoblast cells epithelial cells of the uterine wall. The release protein digesting enzymes, next stage occurs the association of allowing the tropoblast cells to and microvilli and adhesions penetrate into the endometrium. Apart with the uterine wall. In pigs and horses from making a hole which is essential the association is an area which is the for implantation, the breakdown of the site of diffusion activity between endometrial wall which is rich in chorions and villivilli (cotyledons). nutrients is also important for a fuel source and metabolic feedstock 3. Types of Implantation Furthermore, the tropoblast plasma 1. Interstitial implantation occurs in membrane degenerates to form a humans, chimpanzees and guinea multinucleated syncytium which later pigs where the invasion of the becomes the fetal placenta. embryo damages the uterine stromal Endometrial tissue that undergoes tissue so deeply that the embryo modification at the implantation site is enters the stroma and the surface of called the decidua. By responding to the the uterus will cover the area where chemical methods released by the embryo entered. blastocysts, endomterial cells secrete 2. Implantation of eccentrics such as in prostaglandins which locally cause rhesus monkeys, dogs, cats and mice, increased vascularity, edema and stromal damage occurs only partially increased nutrient storage. When and the developing embryo is still implantation is complete, all blastocysts associated with the uterine lumen. are immersed into the endometrium 3. In superficial implantations such as in and tropoblast cells continue to digest horses, pigs, cattle, sheep and goats, the surrounding decidual cells to adhesions only occur on the surface provide energy for the embryo until the of the uterus and relatively do not placenta is formed. occur. The endometrium around the implantation results will recover so that all implantation results are implanted in the endometrium. Along with the

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Figure 1. Fertilization

Figure 2. External fertilization

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Figure 3. Internal fertilization

Figure 4. Structure of the ovum

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Figure 5. Fertilization Process

Figure 6. Division by amitosis

Figure 7. Mitotic Cleavage

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Mitosis I: Prophase Figure 8. The Profase Stage

Mitosis: Metaphase Figure 9. Metaphase Stage

Mitosis: Anaphase Figure 10. Anaphase Stage

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Mitosis: Telophase Figure 11. Telophase Stage

Mitosis: Cytokinesis Figure 12. Cytokinesis

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Meiosis I Figure 13. Meiosis I

Figure 14. Meiosis II

Comparison Factor Mitosis Meiosis The number of cleavages One time cleavage Twice cleavage Number of daughter cells and two, each diploid (2n) and Four, each haploid (n) contains genetic composition genetically identical to the half of the chromosome parent number of the parent cell is not genetically identical to the parent cell and with each other Homologous chromosome not occur Synapses are unique to meiosis synapses during prophase 1. Homologous chromosomes join their bodies, forming tetrads (groups of 4 kroatids), synapses cause crossovers

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between chromatids Place Happened Occurs in the cells of the body Occurs in the reproductive organs Role For cell multiplication, growth, For the formation of sex cells repair and cell reproduction

Figure 15. Comparison of Meiosis and Mitosis

Figure 16. Cleveage

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Figure 17. Zygote cell division

Figure 18. Morula cells

Figure 19. Blastula Cells

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Figure 20. Gastrula Cells

And the sequence of cell division events in question is as follows:

Figure 21. Development of Cell Division

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cleavage. 4. Conclusion 2. Fertilization phase is the meeting Conclusion From the above discussion it between sperm cells and ovum cells can be concluded that: and will produce zygote. Zygote will 1. Fertilization or fertilization perform cell division (cleavage). The (singami) is the fusion of two zygote then undergoes growth and gametes which can be either a development through stages, nucleus or nucleated cells to form a namely division, gastrulation, and single cell (zygote) or nucleus organogenesis. fusion. The process starts with the 3. Implantation or also known as preparation of ovum and oxidation is the process of spermatozoa cells; penetration; implanting the embryo, which is the core incorporation; and early zygote result of conception, into the

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uterine wall (endometrium) to accessed on 27 November 2014 further develop. 6. http://www.medicinesia.com/kedpes- dasar/reprodroduction-kedkes- References dasar/fisiologi-awalkehegaran- 1. Anonymous, 2008. Accessed from implantasi-plasenta-dan-adap- http://id.wikipedia.org/wiki/Pembuahan maternal/. Retrieved 27 November . on November 27, 2014 2014. 2. Anonymous, 2008. Accessed from http: 7. http://goth- //Harunyahya. contemplating id.blogspot.com/2012/04/implantasi- creation.html. on November 27, 2014 nidasi-dan-plasentasi.html?m=1. 3. Anonymous, 2008. Accessed from http: Retrieved 27 November 2014. // Biology of pregnancy and 8. http://drprima.com/kehegaran/minggu- childbirth.html. on November 27, 2014. ke-empat-kehegaran-implantasi- 4. http://reprodroductionumj.blogspot.co menempel-padarahim.html. Retrieved m/2011/08/fertilisasiproseskehegaran.h 27 November 2014. tml#sthash.wJ BFtX3P.dpuf, accessed on 9. http://elianasinta.blogspot.com/2011/0 27 November 2014 1/fertilisasi-dan-implantasi.html?m=1. 5. http://perpustakacyber.blogspot.com/2 Retrieved 27 November 2014. 012/12/proses-fertilisasi-gestasi- kehegaranpersalinan-manusia.html,

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