Human Reproductive Anatomy Explained

Task 1

Question 1 (1.1)

Draw and embed 2 large diagrams showing the male and female reproductive systems. Ensure that your diagrams are fully labelled.

Answer: The labelled diagram of female and male reproductive systems are given below:

Using the two diagrams you have drawn to assist you; describe in detail the structure and function of the human male and female reproductive systems.

Answer: Detailed structure and function of the human female and male reproductive systems are mentioned below: (Jones, et al, 2013)

Female reproductive system is made up of major organs like, ovary, cervix, uterus , vagina, endometrium and fallopian tube. Their structure and functions are elaborated here in this section. (Clarke, et al, 2010)

Ovary: They are the major part of the female reproductive system and are of two in number. Ovaries are whitish in colour and they are located together with the lateral wall part of uterus, this region is termed as ‘ovarian fossa’. They have a shape of bean and the size is 4×2.5×1.5 cm, situated on both side of the fallopian tubes’ free ends. They are hanged by a peritoneal fold from the broad ligament and they are called mesovarium.

Function: Ovaries function is to generate ovum (female gamete) and also it secretes the hormones oestradiol. (Clarke, et al, 2010)

Cervix: It is situated at the neck part of the uterus and protrudes to the vaginal beginning. It connects the uterus with the vagina. Cervix is made up of two major parts endocervical canal and the ectocervix.

Function: During reproduction the cervix helps to free passaging of the sperm into the uterine cavity and also helps to maintain the sterility of the reproductive tract in female specifically for the upper part. (Clarke, et al, 2010)

Uterus: This is one of the most important secondary sex organ in female reproductive system. They are pear-shaped and location is between the bladder and the rectum. Uterus is in the length of 6-8 cm (2.4-3.1 inch) and the width are variable generally it is 6 cm at the fundus part and half at the isthmus part of the uterus. The cavity of the uterus opens in the cavity of vagina and this common part is termed as birth canal.

Function: Uterus acts as a functional ground of acceptance of the ovum after fertilization and will passes through the junction named utero-tubal from the part of fallopian tube. Eventually uterus becomes house for the fertilized ovum to become the embryo by implanting it in the wall of the uterus, which then produce placenta and development of foetus occurred there until the child is born. (Clarke, et al, 2010)

Vagina: It has a canal like structure to join the cervix with the outer part of the body. This canal part is made up of soft elastic muscle and has a lining that is flexible and gives the lubrication. The entrance part of the vagina is labia and the vulva and they are ended at the beginning of the cervix.

Function: It helps during the time of reproduction to receive the penis and helps in ejaculation. During child birth also it acts as a channel to deliver the baby and during menstruation the blood from the uterus comes out from the body with the help of this canal. (Clarke, et al, 2010)

Endometrium: This is one of the major part of the female reproductive system, it is basically the inner lining of the uterus and is a columnar epithelial layer along with the mucous membrane.

Function: It plays a major role to maintain the pattern of the uterine cavity by preventing the adhesion of the myometrium wall and it provides an optimum environment for the blastocyst to get implanted into its wall. (Clarke, et al, 2010)

Fallopian tube: This tube like structure has four parts like, Fimbriae, Infundibulum, Ampulla and Isthmus.

Function: Its main function is to transfer and transport the ovum from the ovary to the uterus. The inner mucosal layer helps to freely move the ovum and also helps in nutrient supply. The muscle layer helps to the contraction which lead to transfer of sperm and ovum. (Clarke, et al, 2010)

Male reproductive system is made up of major organs like, testes, penis, scrotum, prostate gland, epididymis, seminal vesicle and vas deferens. Their structure and functions are elaborated here in this section. (Creasy, et al, 2013)

Testes: It is the major reproductive organ of human male and are two in number. Its length is 4-5 cm and having diameter of 2-3 cm and wight is 25 grams. They are covered with the fibrous tissue structure named as tunica albuginea and are segmented by the tissue to form 200 to 400 lobes. Each wedge-shaped lobes have 3 to 10 tubules known as seminiferous tubules. Two types of cells are mainly found in testes, one is germ cell and another is Leydig cell or interstitial cell.

Function: the major function of testes is to produce sperm. The germ cell develops to produce sperm cell in the seminiferous tubules and testes is also responsible to produce primary sex hormone testosterone in male. (Creasy, et al, 2013)

Penis: This sex organ helps in sexual intercourse and is composed of three parts the roots which is attached to the abdomen, the body and the cone like structure in the end known as glans.

Function: It helps in the ejaculation so semen containing sperm can pass out from it during intercourse and due to its erection the urethra get blocked and only semen will come out not the urine during the intercourse. (Creasy, et al, 2013)

Scrotum: This is a sac like structure which almost like a loose pouch and hanged just below the penis. It contains the testicles and nerves as well as blood vessels.

Function: The function of scrotum is mainly to control the climate of testes as lower temperature is needed to generate sperm than the body temperature , so the muscle present in scrotum will help to regulate the climate by contraction. (Creasy, et al, 2013)

Prostate gland: The walnut shaped structure is situated in front side of rectum and below the bladder. The major function of it is to generate the additional fluid needed for the ejaculation. (Creasy, et al, 2013)

Epididymis: A long coiled tube like structure laid on the backside of testicles called epididymis. Its function is to store the sperm cell produced inside testes. It also bring them to maturity and during arousal and contraction they push the sperm into vas-deferens. (Creasy, et al, 2013)

Vas deferens: It is a connector between pelvic cavity and epididymis, it is a muscular tube and ends behind the bladder. Its function is to carry sperms to urethra. (Creasy, et al, 2013)

Urethra: It’s a tube that carries urine from bladder to outside, for male it also carries sperm cells. During intercourse when penis is erect the urine is blocked and urethra will only pass the sperm cells. (Creasy, et al, 2013)

Seminal vesicles: It is a pouch or sac like body connected to vas deferens. Its function is generating fructose to provide energy to the sperm. (Creasy, et al, 2013)

Question 2 (2.1)

Fig 3 shows changes in the concentration of levels hormones that are involved in controlling the menstrual cycle.

Using figure 3 to assist, explain the chronology of the human female reproductive cycle. You must include details of how the different hormones interact to effectively control the processes of ovulation and menstruation

Answer: Female reproductive cycle is divided into different phases and all of them are regulated by the hormonal influences. They are mainly consist of three phases, follicular phase, ovulation and luteal phase. (Christensen, et al, 2012)

Follicular phase also termed as proliferative phase, here the ovarian follicles get matured by the influence of oestradiol hormone. During the end ending few days of the menstrual cycle the FSH (Follicle stimulating hormone) from pituitary gland get released and its peak shows during first week of follicular phase, its rising level will help to enter into the next menstrual cycle. The increased level of FSH will help to secrete oestrogen by granulosa cell and it will therefore stimulate the release of gonadotrophin releasing hormone (GnRH) so the luteinising hormone (LH) will increase. High oestrogen level during this phase will help the blood flow regulation to form endometrium and the myometrium layer in uterus. Oestrogen level will remain higher throughout the phase. (Christensen, et al, 2012; Barbieri, 2014)

Ovulation will start with highest oestrogen level and just before the surge for LH has begun. Here the drop in the level of oestrogen just before the LH surge may cause spotting (bleeding). In this stage the oocytes undergo first meiotic division. Ovulation then takes place after 30 hrs of LH surge. In the ovulation process of the female menstrual cycle the mature ovarian follicle will rupture to give ovum. This time just surrounded by ovulation termed as ovulatory phase and the ovulation get triggered by the spike release of the LH and the FSH from pituitary gland. (Christensen, et al, 2012; Barbieri, 2014)

Luteal phase stars with the formation of the corpus luteum by the influence of the LH and FSH and the ending is by the start of pregnancy or luteolysis. The major hormone influenced here is progesterone which is produced from corpus luteum and its level is higher throughout the luteal phase and it plays major role to prepare endometrium for implantation. Several days just after the ovulation the secondary surge for oestrogen begins and the hormone secreted by the corpus luteum will decrease the level of FSH and LH. During the death phase of corpus luteum the oestrogen and progesterone level decrease and at the end of this phase the FSH level again rises. (Christensen, et al, 2012; Barbieri, 2014)

Question 3 (3.1)

Human gametes are produced by a type of cell division called meiosis. Explain in detail, with the use of an annotated image, the process of meiosis.

Answer

Answer:

Human gametes during sexual reproduction are produced by the meiotic cell division. It has two phases meiosis I and meiosis II. Four haploid (n) daughter cells are produced from original diploid (2n) cell, so it is reduction division. They occurred in testes and ovaries and termed as spermatogenesis and oogenesis respectively. It starts from the interphase of the cell division, where duplication of the chromosome occurred and produces homologous chromosome from each parents. In meiosis I the homologous chromosome separates to produce haploid cells, termed as daughter nuclei I and then in meiosis II the sister chromatid get separated to give rise four haploid cells (n), termed as daughter nuclei II. (Moens, 2012; Sun, et al, 2012)

The process of producing mature sperm is called spermatogenesis i.e. ‘the creation of sperm’; likewise, the process of producing egg cells is called oogenesis i.e. ‘the creation of oocytes’ or egg cells. Compare and contrast the processes of spermatogenesis and oogenesis in a piece of written work.

Answer: The difference among the spermatogenesis and oogenesis are describes below: (van Werven, et al, 2011)

Question 4 (3.2, 3.3)

To produce a zygote, fertilisation of an egg cell by a sperm cell has to occur. Explain in detail the process of fertilisation within the human body. Your explanation should commence at ovulation and terminate at implantation.

Answer: Fertilization in human body is a complex process which starts from the formation of gametes and up to the implantation of the zygote into the uterine wall. It begins when sperm get fuse with ovum to produce the zygote which is a diploid cell contains half of the chromosome from both the parents. Different phases of fertilization are: ovulation, sperm transportation, egg and sperm fusion, zygote formation and implantation. (Gwatkin, 2012)

Ovulation takes place when the egg releases from the ovary of female and travel through the fallopian tube down where it meets the sperm to get fertilized. (Gwatkin, 2012)

Sperm transportation is a process where sperm get ready first in the vagina after ejaculation by a process known as capacitation, here the Calcium ion concentration increases also the antigens in the sperm coating get lost so the sperm become more receptive to bind to the egg receptor. (Gwatkin, 2012)

Sperm and egg fusion process occurs through a competition by penetrating the layer known as corona radiata in the ovum. This is called the acrosomal reaction when zona pellucida of the ovum helps to secret digestive enzyme from sperm and thus this layer degrades and will make the contact with the oocyte’s plasma membrane. A single sperm will be able to penetrate the corona radiata and zona pellucida and come to contact with oocyte and releases nucleus into the oocytes cytoplasm. (Gwatkin, 2012)

Zygote formation and implantation involves just after the fertilization takes place, when two pronuclei from egg and sperm after 18-20 hrs of fertilization fuses to form zygote. This zygote then undergo a cleavage division in oviduct and through a series of phases in turns to morula and when it reaches uterus is become blastocytes and then it get implanted into the uterine wall. (Gwatkin, 2012)

Sometimes, for different reasons, infertility occurs within the human body. Explain in detail two reasons for infertility in males and two reasons for infertility in females.

Answer: Two reason of infertility in male are problems in ejaculation and chromosomal defect. In case of ejaculation problem the sperm cannot be ejaculated due to some long term medical problem like diabetes, spinal cord injury etc, where semen cannot come out from the penis and in case of chromosomal defect such as Klinefelter’s syndrome, cystic fibrosis, Kallmann's syndrome and Kartagener's syndrome make male infertile. (Bashamboo, et al, 2010)

Two reasons for infertility in female are due to Polycystic ovary syndrome (PCOS) and dysfunction in hypothalamus. In case of PCOS the hormonal imbalance will cause irregular ovulation, which leads to infertility and in case of hypothalamic dysfunction the important hormones like FSH, LH production get disrupted from pituitary gland due to mental stress or overweight. (Tilly, et al, 2013)

In an attempt to conceive a child, a couple who, for some reason, are infertile may decide to try IVF. Discuss in detail the process of In Vitro Fertilisation. You should include an image in your response.

Answer:

In Vitro Fertilization (IVF) is the fertilization procedure which is artificial in nature and occurred outside the body where sperm and egg are fertilized in the test tube environment. (Van Loendersloot, et al, 2010)The steps for IVF are:

Initial screening are done by vaginal ultrasound, blood testing and also testing of seminal fluid. (Van Loendersloot, et al, 2010)

Natural hormone suppression is needed where the injections are given to stop the hormonal regulation for natural ovulation and artificial ovarian stimulation will cause the egg production. (Van Loendersloot, et al, 2010)

Sperm collection is done 60 to 90 minutes before the fertilization. (Van Loendersloot, et al, 2010)

Oocyte collection is done by the trans vaginal ultrasound aspiration by using general anaesthesia. (Van Loendersloot, et al, 2010)

Fertilisation of oocyte is the process where the oocyte is incubated in the sperm containing semen or the injection of intra-cytoplasmic sperm is inserted with microinjection and the sperm and egg cell get fused to produce zygote. (Van Loendersloot, et al, 2010)

Embryo transfer takes place after 3 to 5 days where the catheter contains the fluid and embryo get transferred by the cervix to the uterine cavity. (Van Loendersloot, et al, 2010)

Question 5 (4.1, 4.2)

When couples either feel that their family is complete or they do not wish to conceive children, then contraceptive measures are used. Discuss three separate methods of contraception that do not contain hormones, with regards to method of use and effectiveness

Answer: Three separate methods for contraception are:

Long-acting reversible contraception (LARC) is the method used for long term contraception either by implanting intra-uterine device or by using implant.( Mestad, et al, 2011). This method that includes the intrauterine devices and the implants that are subdermal are most advantageous as they are not user dependent, thus the failure rate is very low almost less than 1%. The success rate of this process is thus higher. The use of LARC is England has successively decrease the percentage of child abortion among teenagers. (Connolly, et al, 2014)

Barrier method is one of the most common method for short term contraception. Here condoms and also internal condoms are used for the sake of protection. (Roth, et al, 2016). The close end of the condom covers the cervix and open end is positioned in the vagina and when this is used correctly and every time the prevention of pregnancy rate is 90% and also effective to protect the sexually transmitted diseases (STD). (Burton, et al, 2020)

Sterilization is another permanent contraception method to prevent the future pregnancy. This can be done by vasectomy or by tubal ligation, in case of vasectomy the vas deferens tube are cut permanently so no sperm will be present in the semen and in case of tubal ligation both the fallopian tubes get closed so that sperm cannot enter into it. (Fletcher, 2015). Tubal ligation is 99% successful to prevent the pregnancy and 1 out of 100 people get pregnant each year after implementing this sterilization procedure. (Gentry-Maharaj, et al, 2017)

Explain how hormones are commonly used within the human body as a contraceptive measure.

Answer: There are many forms of hormonal contraception, as the hormonal regulation control the menstruation and the pregnancy so by controlling the hormonal cycle it is possible to control the rate of pregnancy. Different types are like, using birth control pills, vaginal ring, the skin patch that are contraceptive and the contraceptive coils that releases the hormone (Sadler, et al, 2010). Hormonal regulation is one of the most authentic way to prevent the pregnancy but it cannot protect against the STDs and as it is user dependent thus the success rate depends on the user’s mode of practice. The contraceptive pills used contains two hormones, estrogen and progesterone, which are inserted in small amount and will act against the natural hormonal cycle and will reduce the chance to get pregnant. (Johnson, et al, 2013).

Task 2 (5.1)

Essay: Pick and Mix

According to Pang et al. the designer babies are made from the selected embryo through a genetic selection where specific traits are selected to decrease or eliminate the risk of inherited diseases (Pang, et al, 2016). Here the method is based on the preimplantation genetic diagnosis (PGD) by which a series of embryos are screened by genetic screening and only the embryo contains specific and the desirable traits/genetic makeup they get selected and also on other way the genetic makeup of the baby can be selected before the birth. Designer baby can be produced either by PGD or by human germline genetic engineering. In case of PGD the embryos are selected prior to implantation which can be performed by IVF and then embryo culture where the embryos genetic makeup can be screened by biopsy from embryo sample and then screening through PCR or FISH techniques and after this only the desired embryo get implanted. On other hand human germline genetic engineering is a process where the genetic makeup are changed at the germline level like in the sperm or in ovum and the change is itself heritable. In this era of using multiple gene editing tool as well as mitochondrial gene transfer this procedure is not difficult at all but there is always a higher chance of risk factors for the elimination of heritable traits and insertion of new traits in a selective manner.(Murray, 2014) Professor Wilkinson stated some valid ethical issues regarding the Pick and Mix strategy for making designer babies (Wilkinson, 2013). There are two recent news has been provoked the fact on the use of mitochondrial replacement therapy (MRT) for making designer baby in UK. The child born by using the next generation sequencing (NGS) and this leads to the baby born without having any mitochondrial inherited genetic diseases (Fogleman, et al, 2016). But sometimes this terms misleads with the parents desire to create a baby with the physical traits they would like to have, which seems to be unethical. Heather Long in this context put the thought that one should be very clear that making designer baby and especially the term designer does not signifies any physical trait and the demi-God creation as it is not been selected that whether the child will be taller, fairer etc. This may lead to the use of the concept of Eugenics and Heather Long also support this fact that making designer baby should be disease free objective based fact not any kind of selection on physical appearance will be appreciated. So according to the principals of UK’s existing laws and ethical practices on testing and selection only illness rate and still birth cases has to be reduced by this MRT methods (Burrell, 2013). Also another issue is to be considered here as this techniques are only affordable by a class of people in the society so there will be also vast discrimination while creating the designer babies. Professor Alison Murdoch stated that UK Government can look forward to this matter that those couples who are genuinely have genetic problem that are inherited can have the permission of MTD by using IVF for the selection. The mother who has abnormal mitochondrial DNA will get the chance to have normal child with the help of donor mitochondrial DNA, where the nuclear DNA will be transferred to the active egg having normal mitochondrial DNA from the donor. (Fitzgerald, et al, 2013; Michailidou, 2019; Ly, 2012)

The diseases that can be eliminated by using this technique are due to single mutation in genes like the, cystic fibrosis, Tay-Sachs disease, sickle cell anemia, and Huntington's disease. The genetic alteration should be done with extreme care so that there will be no chance to incorporate new disease in the course of genetic manipulation and can be inherited through different generation. The main process of producing designer baby is based on the biopsy of single or multiple cell of embryo followed by cell lysis. The cell lysis is done to check three types of techniques. The first one is nested PCR where the heteroduplex formation is facilitated followed by mini-gel analysis and fragment size analysis. In the second procedure fluorescence PCR is done in multiplexed manner then automated sequencer is used to analyze STR (short tandem repeat) and detection of mutation. In the third procedure whole genome amplification is done for SNP genotyping by using microarray method or sequencing (next generation). These combined process gives result about combined cytogenetic and analysis of universal linkage by karyo-mapping. Wilkinson et al, discussed on a series of ethics based on embryo selection and the role of Eugenics on it. These give rise to a number of questions like what actually mean by Eugenics and whether these practice fall under Eugenics or not. Actual moral cause of this practice to avoid the transmission of faulty gene to the next generation, the parents who do not have any objection of having baby with certain disability cannot be forced to have a designer baby, the chose of gender and other physical appearance should be strictly prohibited or not. The basis of this arguments and controversies are mostly philosophical as the role of eugenics has to evaluated by thorough care, as the topic is highly controversial and out of the ethics as it is an attempt to improve human gene pool but most of the cases in a racial manner. (Wilkinson, et al, 2013) The controversy is related to eugenics but the PGD can never be termed as eugenics because it only give the permission to eliminate disease trait to pick and mix but not all the physical traits that are acceptable to certain population biasness.

References

Barbieri, R.L., 2014. The endocrinology of the menstrual cycle. In Human Fertility (pp. 145-169). Humana Press, New York, NY.

Bashamboo, A., Ferraz-de-Souza, B., Lourenço, D., Lin, L., Sebire, N.J., Montjean, D., Bignon-Topalovic, J., Mandelbaum, J., Siffroi, J.P., Christin-Maitre, S. and Radhakrishna, U., 2010. Human male infertility associated with mutations in NR5A1 encoding steroidogenic factor 1. The American Journal of Human Genetics, 87(4), pp.505-512.

Burrell, C., 2017. Mitochondrial replacement therapy and ‘three‐parent children’—who should be registered as the legal parents?. BJOG: An International Journal of Obstetrics & Gynaecology, 124(7), pp.1056-1056.

Burton, J., Bedford, R., Graham, C. and Nadarzynski, T., 2020. Perceived barriers and facilitators to female condoms among UK based healthcare professionals. The European Journal of Contraception & Reproductive Health Care, pp.1-6.

Christensen, A., Bentley, G.E., Cabrera, R., Ortega, H.H., Perfito, N., Wu, T.J. and Micevych, P., 2012. Hormonal regulation of female reproduction. Hormone and metabolic research, 44(08), pp.587-591.

Connolly, A., Pietri, G., Yu, J. and Humphreys, S., 2014. Association between long-acting reversible contraceptive use, teenage pregnancy, and abortion rates in England. International journal of women's health, 6, p.961.

Fitzgerald, R.P., Bathard, H., Broad, R. and Legge, M., 2013. Reproduction, ethics and heritable deafness: three South Island families express their views. Sites: a journal of social anthropology and cultural studies, 10(2), pp.129-149.

Fogleman, S., Santana, C., Bishop, C., Miller, A. and Capco, D.G., 2016. CRISPR/Cas9 and mitochondrial gene replacement therapy: promising techniques and ethical considerations. American journal of stem cells, 5(2), p.39.

Gentry-Maharaj, A., Glazer, C., Burnell, M., Ryan, A., Berry, H., Kalsi, J., Woolas, R., Skates, S.J., Campbell, S., Parmar, M. and Jacobs, I., 2017. Changing trends in reproductive/lifestyle factors in UK women: descriptive study within the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS). BMJ open, 7(3).

Mestad, R., Secura, G., Allsworth, J.E., Madden, T., Zhao, Q. and Peipert, J.F., 2011. Acceptance of long-acting reversible contraceptive methods by adolescent participants in the Contraceptive CHOICE Project. Contraception, 84(5), pp.493-498.

Roth, M.Y. and Amory, J.K., 2016, May. Beyond the condom: frontiers in male contraception. In Seminars in reproductive medicine (Vol. 34, No. 03, pp. 183-190). Thieme Medical Publishers.

Van Loendersloot, L.L., Van Wely, M., Limpens, J., Bossuyt, P.M.M., Repping, S. and Van Der Veen, F., 2010. Predictive factors in in vitro fertilization (IVF): a systematic review and meta-analysis. Human reproduction update, 16(6), pp.577-589.

van Werven, F.J. and Amon, A., 2011. Regulation of entry into gametogenesis. Philosophical Transactions of the Royal Society B: Biological Sciences, 366(1584), pp.3521-3531.