Structures and Functions of Male and Female Reproductive Systems

The Human Reproductive Systems

Introduction:

Here is my report on the human reproductive system it covers the structure and functions of the male and female reproductive systems, the role hormones play during key developmental stages which include gametogenesis, puberty, pregnancy and the menopause. It also includes the processes and sequence of events during fertilisation, implantation, foetal development and childbirth also the function of the placenta during pregnancy.

Findings:

Male reproductive system:

The male reproductive function is to produce sperm so it can transfer them to the female reproductive tract. The paired testes are very important in this process as they produce both sperm and androgen, testosterone is the most important male hormone as this supports the male reproductive process. The testes are housed in a muscular sack that is called the scrotum and it extends from the behind the penis, the location of the testes is very important in sperm production the testes perform more efficiently if they are kept 2 to 4 degrees below core body temperature. The testes are oval in shape and are approximately 4 to 5cm in length and housed within the scrotum they are surrounded by two distinct layers of protective connective tissue. On the seventh month of the developmental period of a male fetus each testis moves through the abdominal musculature to descend into the scrotal cavity.

Female Reproductive System:

A female reproductive system is made up of internal organs and external structures its function is to enable reproduction of the species but in order for this process to happen her body needs to go through sexual maturation which helps in the process of pregnancy and birth. A woman’s uterus is classed as an organ which is located centrally in the pelvis, the uterus houses the developing fetus during pregnancy, the lower part of the uterus is called the cervix and this opens into the vagina the cervix has an opening which allows passage to sperm so it can get to the uterus and it is also the exit for menstrual blood. The cervix also dilates during labour which allows passage of the baby through the birth canal. In the upper part of the uterus on each side are the fallopian tubes these are the channels that allow eggs from the ovaries to enter the uterus. A female has 1 to 2 million eggs already present in her ovaries when she is born but only 300 of them will mature during her lifetime.

Gametogenesis:

The creation of gametes is called gametogenesis, the general sequence is the same in males and females. The process begins with germ cells they begin to develop and multiply in the embryo the name giving to these are diploid cells they contain 23 pairs of chromosomes to give a total 46 chromosomes. The germ cell replicates its DNA once but divides twice this happens through a process called mitosis.

Puberty:

Puberty happens in both boys and girls when they start to produce a releasing hormone called gonadotrophin this comes from the part of the brain called the hypothalamus. The hormone will stimulate the pituitary gland which then releases two other hormones the follicle stimulating hormone and luteinizing hormone these hormones will then travel through the blood to the testicles and ovaries this then switches on the development procedure which then leads to sexual maturity.

Pregnancy:

During pregnancy your body will release a lot of different hormones the most important ones in play while you are pregnant are:

Oestrogen – this hormone is produced in early pregnancy to help support your baby until the placenta takes over, it also helps with the development of your baby’s organs along with the correct function of the placenta. This hormone can also cause nausea and can make your ligaments softer which puts pressure on your lower back and pelvis, it also helps late into your pregnancy by helping your body prepare for breastfeeding.

Progesterone – this hormone is also produced in early pregnancy to support your baby it causes an increase in blood flow to your womb, it is said that this hormone is the one that could be responsible for the heartburn, vomiting, reflux, gas and constipation. It will also help with your baby’s development and prevent you from producing milk until your baby is born and it also strengthens your pelvic floor muscles ready for labour.

Oxytocin – this hormone helps to ease your pain while you are in labour it also encourages the cervix to open and also plays a major role in your milk production and helps you to bond with your baby.

Prolactin – this hormone helps you to bond with your baby.

Relaxin – this hormone makes your ligaments softer which means you will have to adjust certain types of exercise, so you don’t get any injuries. It also helps when you’re in labour as it softens and lengthens the cervix as well as the pelvis area.

Human chorionic gonadotropin – this hormone is released into your bloodstream as soon as you get pregnant to support your baby and is also the hormone that indicates whether your pregnant or not with the over the counter pregnancy tests.

Human placental lactogen – this is the hormone that helps your baby get the nutrients it needs while you’re pregnant.

Prostaglandins – this hormone helps to get the cervix ready for labour.

Menopause:

The menopause happens when the number of ovarian follicles declines and the ovaries become less responsive to the two hormones involved in reproduction, when your ovaries age and release fewer hormones they can no longer preform their usual function to regulate your estrogen, progesterone and testosterone.

Events during fertilisation, implantation, foetal development and childbirth:

Fertilisation happens when sperm is deposited into the vagina this must occur no earlier than three days before or within one day after ovulation. The egg will remain in the fallopian tube alive and fully functioning for only 12 to 24 hours, but sperm can live longer in the female reproductive system it can live for up to 72 hours, but most will die before this. In the fertilisation process only one sperm will succeed in fertilising the egg this happens when the sperm penetrates the cell membrane and depositing the male genetic material into the female cell the two then fuse together. When the egg has been fertilised up until the eighth week of pregnancy the developing human is called an embryo. How this process happens is it first divides into two cells then they each divide again to give four cells this is known as cell division which is repeated many times until a solid ball of cells are formed this is called a morula and is produced after three days. After five days a hollow ball of cells is then formed called a blastocyst between five to seven days after fertilisation the blastocyst reaches the uterus and embeds itself in the lining of the uterus this is than called implantation and if the embryo survives it is the start of pregnancy. But on some occasion’s implantation can occur in the fallopian tube this is called an ectopic pregnancy and is very dangerous for the woman. Every woman’s labour is different or as some may say unique, for some woman labour is over in a matter of hours for others labour likes to test a mothers physical and emotional stamina. Labour is played out in three stages the first stage and the longest is early labour and active labour, early labour is when your cervix dilates and you’ll feel mild irregular contractions but when you’re in active labour your cervix would have dilated from 6cm to 10cm and your contractions become stronger and closer together. Stage two is the birth of your baby now this process can take a few minutes to a few hours which can be longer for first-time mam’s or women who have had an epidural. Now we are at stage three which is delivery of the placenta now this can take around five to thirty minutes, but the process can last as long as an hour.

The Placenta, which is a temporary organ is required for the development of the embryo and fetus. The job of the placenta is to exchange nutrients and oxygen between the mother and fetus, it also transfers the foetal waste products back to the mother for disposal by her organs. During the pregnancy there is no mixing of maternal and foetal blood in the placenta, it also tries to prevent harmful substances from making this journey. The placenta will allow some proteins and bigger chemicals in the blood like maternal antibodies which will stop infectious agents like bacteria from getting into her body while she is pregnant allowing this is important as it provides protection for the fetus and then later the new-born baby. But the placenta cannot prevent the transfer of alcohol and drugs and these agents can cause birth defects.

Conclusion:

On conclusion I have learnt that the function of the male reproductive system is to produce sperm and transfer them to the female reproductive tract and testosterone is the most important male hormone as this supports the male reproduction process, the female reproductive system’s function is to enable reproduction of the species but in order for this to happen the female needs to go through sexual maturation and a females uterus is classed as an organ. The creation of gametes is called gametogenesis and the sequence is the same in males and females, puberty happens in boys and girls when they start releasing the hormone gonadotrophin. During pregnancy the body releases eight different hormones and all of these help your body with different aspects of your pregnancy, menopause will occur when you’re body becomes less responsive to the two hormones involved in reproduction, an egg can remain alive and fully functioning for between 12 to 24 hours while sperm can last for up to 72 hours, it takes between five to seven days after fertilisation for implantation to happen and the placenta is a temporary organ that allows the exchange of nutrients and oxygen between the mother and fetus.

References:

• Stoppler. M, Female reproductive system https://www.medicinenet.com/female-reproductive-system/article.htm#what-do-the-reproductive-organs-look-like-picture
• Anatomy and physiology pg. 187 chapter 27.1 The reproductive system https://opentextbc.ca/anatomyandphysiology/chapter27-1-anatomy-and-physiology-of-the-male-reproductive-system/
• Fertilisation, implantation and the foetal and placental circulation. Antenatal care module 5 http://www.open.edu/openlearncreate/mod/ovcontent/view.php?id35&
• How hormone depletion affects you, North-western University 2013. https://www.menopause.northwestern.edu/content/how-hormone-depletion-affects-you
• Labour and delivery by the Mayo clinic staff https://www.mayoclinic.org/healthy-lifestyle/labour-and-delivery/in-depth/stages-of-labour/art-20046545
• Contents page:
• Page one – Introduction, findings: male reproductive system, female reproductive system.
• Page two – Findings: female reproductive system continued, gametogenesis, puberty, pregnancy.
• Page three – Findings: pregnancy continued, menopause, events during fertilisation, implantation, foetal development and childbirth.
• Page four – Findings: events during fertilisation, implantation, foetal development and childbirth continued, conclusion.
• Page five – Conclusion continued, references