Illustrated Report Human Reproductive Systems PDF

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Human reproductive systems, illustrated report.
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The Human Reproductive Systems - An Illustrated Report Due date: 11/10/2021 Unit code: RH33MR047 Word Count: 1996

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Contents Page 1 – Title Page Page 2 – Contents Page 3 - Introduction Page 4 - 5 – Section 1 – Male Reproductive System Page 5 – 6 – Section 1 – Female Reproductive System Page 7 – Section 2 – Puberty and gametogenesis Page 7 – 8 - Section 2 – Puberty in Boys and Spermatogenesis Page 8-10 – Section 2 – Puberty in Girls and Oogenesis Page 10 – 11 – Section 2 – Pregnancy Page 11 – Section 2 – Menopause Page 12 – Section 3 – Fertilisation Page 13 – Section 3 – Implantation Page 14-15 – Section 3 - Foetal Development Page 15 – 16 – Section 3 - Childbirth Page 17 – Section 4 – The Placental Function During Pregnancy Page 18 – Conclusion Page 18 – Recommendations Page 19 – 20 – References Page 21 – 23 – Bibliography

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Introduction

This report’s purpose is to demonstrate understanding of the human reproductive systems. Using study materials provided by Stonebridge College and further resources online, these areas will be covered: • • • •

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Structure and functions of male and female reproductive systems. Roles of hormones during key developmental stages: gametogenesis, puberty, pregnancy, and menopause. Processes and sequence of events during fertilisation, implantation, foetal development, and childbirth. Placental function during pregnancy.

Section 1 – Structure and Functions of the Reproductive Systems Male Reproductive System This is responsible for making, maintaining, transporting sperm. Depositing sperm inside the vagina during sexual intercourse, and production and secretion of hormones.

Figure 1: Male Reproductive System (Front View) BioNinja

The Testes • •

Responsible for spermatogenesis. Creates testosterone.

The Penis • • •

Responsible for penetration. Deposits semen during intercourse, into the vagina. Passes urine out of the body from the bladder.

The Seminal Vesicle • • •

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Positioned at the back of the bladder. Each have a duct joining the deferent duct, consequently forming the ejaculatory duct, which “passes through the prostate gland and then into the urethra.” (Strohm, K). The seminal vesicles secrete a slightly alkaline fluid, which nourishes spermatozoa. This fluid counteracts the slight acidity in the urethra and inside the woman’s vagina (CrashCourse, 2015. a).

The Prostate Gland •

Produces prostatic fluid that help to keep sperm liquid. This fluid is squeezed out into the urethra during ejaculation (CrashCourse, 2015 a). This helps sperm “swim freely while in the female body” (Bennington-Castro, J. 2015).

Female Reproductive System This is responsible for producing gametes, receiving male gametes, providing an environment that is suitable to fertilise and develop a foetus, and providing the exit for the fully developed foetus during parturition.

Figure 2 - Female Anatomy: The Reproductive Organs (Brichford, C. 2016)

The Ovaries •

They “produce and release female gametes and sex hormones” (CrashCourse, 2015).

Fallopian Tubes • • •

Approximately 10cm long. Lined with cilia and muscles, they propel the eggs movement down the tube. Fertilisation occurs here.

Uterus • •

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The uterus is a “hollow, thick walled, stretchable organ.” (CrashCourse, 2015). Makes a home for the developing foetus.

Cervix • •

Keeps the baby in place throughout the pregnancy. Allows sperm in and menstrual blood out. Menstrual blood exits via the cervical canal. When childbirth comes, this cervical canal expands during labour to create the exit.

The Vagina •

The lower third of the vagina is lined with elastic muscles which control the diameter of its opening, allowing for penis entry during sexual intercourse and the baby to exit during delivery.

The Mammary Glands • •

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An external organ. Contain lactiferous ducts within them within the nipple produce milk after birth.

Section 2 – Role of Hormones During Key Developmental Stages Puberty and Gametogenesis Puberty’s when “adolescents reach sexual maturity and become capable of reproduction.” (Lexico), beginning between the ages of 10-16 years. Puberty leads to gametogenesis (where gametes are produced). Gametes are male and female sex cells (sperm and ovum). Sperm is produced by spermatogenesis and the ovum, produced by oogenesis.

Figure 3: Physical changes boys and girls experience during puberty (Ageless Media, 2018).

For males and females, puberty begins in this way: 1. Hypothalamus releases gonadotropin-releasing hormone (GnRH). 2. Release of GnRH tells the anterior pituitary to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH) into the bloodstream.

Puberty in Boys and Spermatogenesis In boys, steps 1 and 2 result in: • •

LH that was released from the anterior pituitary, tells the Leydig cells in the testes to make, and secrete testosterone, consequently stimulating spermatogenesis. FSH that was released also stimulates spermatogenesis, and acts on the Sertoli cells, which are sperm nourishing cells. (Khan Academy)

Testosterone causes physical changes, some of which can be seen in figure 3.

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Figure 4: Spermatogenesis at a Glance (Khan Academy)

Spermeotogenesis has a multiplication phase, growth phase, maturation phase and spermiogenesis, whereby through mitosis and then mieosis, a spermatagonia becomes 4 spermatozoa. This is an ongoing process for males from puberty, caused by hormones.

Puberty in Girls and Oogenesis In girls, steps 1 and 2 stimulate a follicle to grow within the ovary, which releases oestrogen causing the physical changes in Figure 3 to take place. The FSH released will stimulate a follicle within the uterus to grow, which releases oestrogen making the follicle mature more. It then communicates to the pituitary to release more LH to trigger the oocyte to divide further. This LH released will cause ovulation.

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Figure 5: Oogenesis (LibreText, 2020)

Like spermiogenesis, oogenesis has a multiplication phase and a growth phase. They then go on to: Phase 3 – Maturation Meiotic maturity division 1: •

The Primary oocyte divides into 2 haploid daughter cells: - Secondary oocyte - Polar body.

Meiotic maturity division 2: •

The secondary oocyte divides into 2 cells. - One ovum, frozen in metaphase II until ovulation. - Another polar body.

Ovulation – • • •

Follicle then pushes against the ovary wall and releases the mature, oocyte into the fallopian tubes. If fertilised, oocyte moves through meiosis. Ovulation occurs monthly from puberty-menopause.

Corpus Luteum – • •

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Follicle reduces its release of oestrogen and morphs into the corpus luteum which releases progesterone, oestrogen, and inhibin, preparing the uterus for an oocyte. They also message to stop FSH and LH being released. (CrashCourse, 2015).

Figure 6: Phases of the Menstrual Cycle (Brighten, J)

If the egg is not fertilised, the menstrual cycle continues, the endometrium layer sheds, causing a period, which lasts around 5 days. Next, oestrogen repairs the lining causing it to thicken preparing for a mature oocyte to be released again.

Pregnancy During pregnancy many hormones active in a woman’s body and all have their own purposes. They are: •

Oestrogen -

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Supports the baby prior to the placenta, Helps the development of organs in the baby and the functioning of the placenta. Later in pregnancy, oestrogen helps prepare the body for breastfeeding.

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Progesterone Increases the blood flow to the womb. Helps to develop the baby Strengthens the pelvic floor muscles in preparation for labour.

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Oxytocin

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Prolactin

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Relaxin

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Eases the pain during labour, Encourages the cervix to open Encourages milk production and bonding.

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helps with bonding.

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makes the ligaments softer which helps in labour as it softens the cervix and pelvic area.

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Human Placental Lactogen (hPL) - assists baby getting nutrients needed whilst pregnant.

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Prostaglandins - Helps get cervix ready for labour.

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Human Chorionic Gonadotropin (HCG) the indicator for a positive pregnancy test - Supports the mother and baby.

Menopause Menopause occurs in women aged approximately 50-55 years. In menopause the number of eggs in the ovary decreases leading to a decline of oestrogen levels. When this occurs, symptoms occur, known as perimenopause. These symptoms can include changes to frequency of periods, hot flushes, and night sweats (NHS, 2018). These symptoms can last years when eventually, due to the decrease in hormones, the menstrual cycle stops completely. This is known as the menopause. Mature eggs can no longer be produced, ovulation cannot occur, and neither can pregnancy from this point (Strohm, K).

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Section 3 –Fertilisation, Implantation, Foetal Development and Childbirth Fertilisation Fertilization is when a sperm, meets the ovum and then penetrates it. When an ovum is released from the ovary it may meet a sperm upon traveling through the fallopian tube. If this happens the sperm may be able to penetrate the ovum using the below method.

Figure 7: Female Reproductive System: Fertilisation (The Histology Guide)

• • • •

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Prior to step one in image 7, the sperm undergoes capacitation which helps the sperm to be more motile. The sperm binds to the zona pellucida. An acrosomal reaction occurs where the acrosome, in the sperms head releases chemicals which bury through the membrane. The sperm then goes onwards to the cell membrane and burrows its way in eventually entering the cytoplasm. (Nerd, N. 2017).

Implantation “Implantation refers specifically to the attachment of the fertilized egg to the uterine lining” (MedicineNet). Implantation occurs 6-12 days after ovulation. Prior to implantation the zygote undergoes cell division by mitosis, therefore cells are increasing in number: • •

At 8 cells, it’s called a morula At 32 cells, it’s called a blastocyst (Hasudungan, A. 2014).

Then the blastocyst will shed the zona pellucida and implant itself into the endometrium, in the uterine lining where it can get nourishment from the mothers’ blood supply.

Figure 8: How Long After Ovulation Does Implantation Occur? (Ovulation Calculator)

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Foetal Development During foetal development there are three trimesters: • • •

First – 0-13 weeks Second – 14-26 weeks Third – 27-40 weeks

Up until 8 weeks, it is known as an embryo. From 9 weeks onwards, it is known as a foetus.

Figure 9: Stages of Embryonic and Foetal Development (Strohm,K)

Key milestones in embryonic and foetal development: • • • 14

4 weeks - the embryos heart is beating. 8 weeks – it’s now known as a foetus and its form is recognisably human. 9 weeks - the sex of the foetus can be discovered.

• • • • • •

12 weeks - it has all its internal organs. 16 weeks - the first kicking movements are commonly felt. 20 weeks - all major organs have been formed; it may have started even growing hair. 26 weeks - the foetus has a reasonable chance of survival if born prematurely. 35 weeks - fat deposits increase. 38 weeks - birth usually takes place.

Childbirth Childbirth usually takes place 38 weeks after conception. “Birth, or parturition, is the transition between the prenatal and postnatal periods of life” (Strohm, K). Labour results in birth. In a woman’s first pregnancy it lasts approximately 12-18 hours.

Figure 10: Stages of Childbirth (Lila, 2018)

The 3 stages of labour:

Stage 1 – Dilation –There are 3 phases of stage 1. (Lila, 2018)

Phase 1 – Latent Labour

Phase 2 – Active Labour Phase 3 - Transition

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-Cervix Dilates to 3-4 cm. -Contractions soften the cervix. -Contractions can be timed at this stage. -Cervix Dilates to 5-9cm in this stage. -Strong contractions, every 3-4 minutes. -Cervix dilates to 10cm. -Transitions into delivery.

Stage 2 – Delivery –The birthing stage. The infant moves through cervix, down the birth canal and exits via the vagina.

Stage 3 – Delivery of Placenta – The umbilical cord is cut. Then strong contractions dislodge the placenta from the uterine wall, and then its delivered. (CrashCourse, 2015 b).

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Section 4 – The Placental Function During Pregnancy The Placenta is the only transient Organ in the body, meaning it grows and then leaves. It’s formed with some cells from the embryo and some cells from the mother.

Its main functions are:

1. Providing nutrients to the foetus from the mother, including oxygen.

2. Removing waste from the foetus, including CO2. 3. To protect the foetus by not allowing mothers blood to mix with the foetus’ blood. 4. Managing hormone levels during pregnancy.

Figure 11: Placenta (Wikipedia)

The placenta releases hormones throughout pregnancy and labour. A few weeks before birth, the placenta stops releasing progesterone to the uterus which had been responsible for keeping the muscles in the uterus relaxed. The Placenta then releases more oestrogen at this stage for birth preparation. (CrashCourse, 2015 b). As labour approaches, the foetus secretes oxytocin, which tells the placenta to release prostaglandins. The combination of these two hormones stimulates the uterine muscles to begin contracting (CrashCourse, 2015 b). Factors that can lead to a decline in the performance and health of the placenta: 1. 2. 3. 4.

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Blood pressure – high blood pressure or sudden increases. Multiple pregnancies – pregnancy involving more than one baby. Trauma – physical trauma can weaken it. Age – Mothers post 40 due to hormone regulation issues.

Conclusion To conclude, the male and female reproductive systems are incredible. They work together in harmony to create a life, with so much work going on behind the scenes. Every small detail involved is vital for the processes to work and even the smallest thing out of place in the process could be detrimental.

Recommendations Following this report, this area is so vast and interesting, I discovered that I struggled with the word count due to further research and potentially expanding on so many points. Better assignment planning would have been beneficial and more time off work to study.

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References Ageless media (2018) Physical changes boys and girls experience during puberty Ageless Media [online] Available at: https://www.agelessmedica.com/physical-changes-boys-girls-experiencepuberty/ Date accessed: 10/10/2021

Bennington-Castro, J (2015) What is PSA? Everyday Health [online] Available at: https://www.everydayhealth.com/prostate-cancer/guide/psa/ Date accessed: 09/10/2021

BioNinja Male Reproductive System BioNinja [online] Available at: https://ib.bioninja.com.au/standard-level/topic-6-human-physiology/66-hormones-homeostasisand/male-reproductive-system.html Date accessed: 09/10/2021

Brichford, C (2016) Female Anatomy: The Reproductive Organs Everyday Health [online] Available at: https://www.everydayhealth.com/sexual-health/female-reproductive-organs.aspx Date accessed: 06/10/2021

Brighton, J Phases of the Menstrual Cycle [online] Available at: https://drbrighten.com/phases-ofthe-menstrual-cycle/ Date accessed: 11/10/2021

CrashCourse (2015) Reproductive System, Part 1. YouTube [online] Available at: https://www.youtube.com/watch?v=RFDatCchpus&t=567s&ab_channel=CrashCourse Date accessed: 26/09/2021

CrashCourse (2015) a Reproductive System, Part 1. YouTube [online] Available at: https://www.youtube.com/watch?v=-XQcnO4iX_U&t=25s&ab_channel=CrashCourse Date accessed: 26/09/2021

CrashCourse (2015) b Reproductive System, Part 4 – Pregnancy and Development YouTube [online] Available at: https://www.youtube.com/watch?v=BtsSbZ85yiQ&ab_channel=CrashCourse Date accessed: 09/10/2021

Hasudungan, A (2014) Embryology Day 07 fertilisation, Zygote, Blastocyst. YouTube [online] Available at: https://www.youtube.com/watch?v=EwTZ1fypivg&ab_channel=ArmandoHasudungan Date accessed: 10/10/2021

Khan Academy Spermatogenesis at a Glance Khan Academy [online] Available at: https://www.khanacademy.org/science/in-in-class-12-biology-india/xc09ed98f7a9e671b:in-in-

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human-reproduction/xc09ed98f7a9e671b:in-in-gametogenesis/a/spermatogenesis-review Date accessed: 09/10/2021 Khan Academy (2015) Spermatogenesis | Reproductive system physiology | NCLEX-RN | Khan Academy YouTube [online] Available at: https://www.youtube.com/watch?v=QUJxnv53UM&ab_channel=khanacademymedicine Date accessed: 08/10/2021 Lexico Puberty Definition Powered by OXFORD Lexico [online] Available at: https://www.lexico.com/definition/Puberty Date accessed: 09/10/2021 Lila (2018) Your Guide to the Phases and Stages of Labour and Childbirth Silver Birth [online] Available at: https://www.silverbirth.com/blog-1/2018/10/22/your-guide-to-the-phases-ampstages-of-labour-amp-birth Date accessed: 11/10/2021 LibreText (2020) 43.4C Gametogenesis (Spermatogenesis and Oogenesis) [online] Available at: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biolo gy_(Boundless)/43%3A_Animal_Reproduction_and_Development/43.3%3A_Human_Reproductive_ Anatomy_and_Gametogenesis/43.3C%3A__Gametogenesis_(Spermatogenesis_and_Oogenesis) Date accessed: 11/10/2021 MedicineNet Medical Definition of Implantation MedicineNet [online] Available at: https://www.medicinenet.com/implantation/definition.htm Date accessed: 10/10/2021

NCT (2018) Pregnancy Hormones: progesterone, oestrogen and the mood swings NCT [online] Available at: https://www.nct.org.uk/pregnancy/how-you-might-be-feeling/pregnancy-hormonesprogesterone-oestrogen-and-mood-swings Date accessed: 11/10/2021

Nerd, N (2017) Reproductive System Fertilisation YouTube [online] Available at: https://www.youtube.com/watch?v=H5hqwZRnBBw&ab_channel=NinjaNerd Date accessed: 10/10/2021

NHS (2018) Symptoms Menopause NHS [online] Available at: https://www.nhs.uk/conditions/menopause/symptoms/ Date accessed: 09/10/2021

Stohm, K [online] Human Reproduction, Growth and Development Pearl Available at: https://atomlms.epearl.co.uk//vle/_store/scorm/1622575561-human-reproduction-growth-anddevelopment-scorm2004-4-xvdpu9tx/scormcontent/index.html Date accessed: 20/09/2021

The Histology Guide Female Reproductive System: Fertilisation University of Leeds [online] Available at: http://www.histology.leeds.ac.uk/female/fertilisation.php Date accessed: 10/10/2021

Wikipedia Placenta Wikipedia [online] Available at: https://en.wikipedia.org/wiki/Placenta Date accessed: 09/10/2021

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Bibliography Ageless media (2018) Physical changes boys and girls experience during puberty Ageless Media [online] Available at: https://www.agelessmedica.com/physical-changes-boys-girls-experiencepuberty/ Date accessed: 10/10/2021

Bennington-Castro, J (2015) What is PSA? Everyday Health [online] Available at: https://www.everydayhealth.com/prostate-cancer/guide/psa/ Date accessed: 09/10/2021

BioNinja Male Reproductive System BioN...