++++ S9: Human Reproduction Flashcards
gametes definition
Gametes are sex cells
Fertilisation definition
Fertilisation happens when the nucleus of the sperm joins with the nucleus of the egg to form a zygote.
Zygote definition
A zygote is a fertilised egg
Explain all of the functions of the parts of the male reproductive system (list 9 in the diagram)
testis: To produce sperm, to produce testosterone
Scrotum: To hold the testis.
vas deferens/sperm duct: A tube carrying the sperm from the testis to the penis. Collects seminal fluid from glands.
Urethra- neck of the bladder: Sperm ducts enter the urethra.
Penis: Passes semen into the female vagina.
prostate glands: Produces part of the seminal fluid.
Seminal vesicles: Produces part of the seminal fluid.
Both secrete seminal fluid to nourish sperm
Mention the following in a diagram: Ureter, bladder, sperm duct, penis, scrotum, testis, urethra, prostate gland, seminal fluid,
What is testosterone and what does it do?
Testosterone is a hormone that controls male characteristics: Development of sex organs Broad shoulders Deeper voice Sex-drive Growth of body hair
Explain all of the functions of the parts of the female reproductive system
Ovary: to produce eggs. To produce oestrogen
Fallopian tubes/oviduct: To collect eggs from the ovary. Where fertilisation occurs.
Uterus/womb: Where a baby grows and develops.
Cervix: Very narrow opening that allows passage between the uterus and the vagina.
vagina: Where the penis is placed during sexual intercourse. The birth canal
Mention all of the above in a labelled diagram.
What is oestrogen and what does it do?
Oestrogen controls female characteristics:
Development of sex organs
Development of breasts
Widening of the hips (In preparation for having a baby)
Growth of pubic and underarm hair.
Where does the word menstrual come from and what does it mean?
The word ‘menstrual’ comes from the Latin word ‘mens’ meaning month.
Menstrual cycle definition
The menstrual cycle is the monthly series of changes a woman’s body goes through in preparation for the possibility of pregnancy.
How long is the menstrual cycle usually?
it is usually 28 days long
Explain what happens during the menstrual cycle for the ovary and uterus (include days)
Ovary: 1-5: egg/s mature 5-14: egg continues to mature 14: egg is released from the ovary - ovulation (it will die soon as it is not fertilised) 14-28: hormones are released 1-5: Another egg/s starts to mature
Uterus:
1-5: menstruation - blood and tissue lost through the vagina.
5-14: blood and tissue are building up in the uterus again
14: blood and tissue continue to build up in the uterus
14-28: Blood and tissue remain built up in the uterus.
1-5: menstruation - blood and tissue is lost from the uterus - through the vagina.
When and what is the fertile period?
The fertile period occurs during the menstrual cycle. Fertilisation leading to pregnancy can occur from approximately day 11 to day 17 of the female cycle.
In order for fertilisation, what must happen? Explain this in detail
In order for fertilisation to happen, there must be an egg and a sperm in the fallopian tube at the same time.
An egg or eggs are usually released into the fallopian tube around day 14 of the cycle. The egg will only live for 12-24 hours after release.
Sperm may survive in the human female system for up to 3 days. This means that sexual intercourse happening three days before ovulation (release of an egg) can result in fertilisation and pregnancy.
It also means that the egg could still be alive up to 2 days after it is released and therefore it could be fertilised as well.
When does sexual intercourse occur? And for this to happen what must occur?
Sexual intercourse occurs when the penis is placed in the vagina.
For this to happen:
the penis becomes stimulated, fills with extra blood and gets hard and erect.
the vagina becomes stimulated and produces fluid which moistens it.
it is then possible for the penis to be placed in the vagina.
Due to further stimulation of the penis ejaculation occurs.
Once the sperm is in the female reproductive system it will move up towards the egg in the fallopian tube. A chemical produced by the egg to attract the sperm causes this to happen.
Once it reaches the egg both cells join together. the nucleus from the egg fuses with the nucleus of the sperm. The resulting cell is called a zygote.
What does a fertilised egg do?
Once the egg is fertilised it becomes a zygote and begins to divide (cell division). The fertilised egg divides many times to form the embryo in the uterus.
Explain the development of a baby
Once the egg is fertilised it becomes a zygote and begins to divide (cell division).
It becomes a ball of many cells and these become the embryo. The embryo makes its way down the fallopian tube towards the uterus.
Implantation takes place 9 days after fertilisation where the embryo arrives in the uterus and attaches to the lining of tissue that is built up in it.
Cell division continues at a faster rate.
At around 7 weeks, when bone starts to develop, the embryo becomes a foetus.
After 12 weeks, all of the systems are formed and now the baby needs to grow and become stronger.
What is the placenta and when is it fully developed?
The placenta is fully developed by around week 12.
The placenta is a mass of tissue that passes nutrients and oxygen from the mother’s blood to the baby and passes waste as carbon dioxide from the baby to the mother’s blood.
How is the baby protected in the uterus?
The baby is protected in the uterus by amniotic fluid which is contained within a skin-like membrane known as the amnion.
What connects the baby to the placenta?
the umbilical cord connects the baby to the placenta.
When is a baby ready to be born?
The baby will continue to grow and develop until around week 40 when it will be ready to be born.
What are the three stages in the process of birth?
Labour, birth and the removal of the placenta
Explain the first stage of birth
- Labour:
The birth canal gets wider.
The amnion bursts and the amniotic fluid flows out. The baby is pushed further down the uterus by contraction of the muscles in the uterus.
Explain the second stage of birth
- Birth:
The muscles of the uterus continue to contract and the baby is pushed through the birth canal to the outside world.
Explain the third stage of birth
3. Removal of the placenta: The placenta (known as the afterbirth) is then pushed out of the uterus.
What is produced in the mother’s body once the baby is born, where?
Once the baby is born the mother’s body produces a hormone that causes milk to be produced by the mammary glands (the breasts).
What are the advantages of breastfeeding?
In the first few days after birth, the milk has extra nutrients and antibodies.
the milk continues to give the baby the right balance of nutrients.
the milk continues to pass immunity to infection from mother to baby.
Breastfeeding promotes a bond between mother and baby.
The baby is less likely to get gastro-enteritis (infection of the stomach and gut).
What is contraception? What are the two types of contraception?
Contraception is preventing pregnancy by preventing fertilisation or implantation.
There are two types of contraception: Natural and artificial.
Explain natural contraception
This involves methods of contraception that are based on knowing the time during the menstrual cycle when the woman is fertile and avoiding sexual intercourse at that time.
There are a number of natural methods of contraception, all of which require training on how to effectively use them.
Being familiar with her cycle also means that a woman can know when she is most likely to conceive should she want to have a baby.
What does artificial contraception mean?
Artificial contraception means using mechanical or chemical methods to avoid pregnancy.
What are mechanical methods of contraception? Give examples
Mechanical methods of contraception means using mechanical methods to avoid pregnancy.
Condom: A sheath placed over the penis to collect sperm after ejaculation
Diaphragm: A specially fitted device placed in the woman’s vagina to prevent sperm from passing into the uterus.
What are chemical methods of contraception? Give examples
Chemical methods of contraception involve using types of chemical to prevent pregnancy.
The pill: A pill with a hormone to prevent the woman from producing eggs each month.
The bar: A rod that is implanted under the skin of the woman. It releases a hormone that works just like the pill.
What does IVF stand for?
In Vitro Fertilisation
Give a simple description of in vitro fertilisation
Eggs are removed from the woman’s ovary.
The eggs are placed in a petri dish with special nutrients.
Sperm is collected from the man and added to the dish.
When the eggs have been fertilised they are left in the nutrients to develop into embryos.
Some of the embryos (usually more than one to ensure success) are then surgically transferred to the uterus of the woman.
Time is allowed for the embryo/s to implant in the uterus.
If the procedure is a success, the woman will become pregnant, the surplus embryos may be frozen to be used at another time.
What does in vitro mean and why is it called this?
In Vitro means ‘in glass’. This name was given to this method of fertilisation because the fusion of the egg and sperm usually happened in a glass petri dish.
What does ethics mean?
Ethics means whether something is right or wrong
What are some ethical issues to do with in vitro fertilisation?
What happens to the frozen embryos when they are no longer needed?
Will the embryos be destroyed?
Could the embryos be donated to childless couples?
Will the excess embryos be used in stem cell research?
Is it ok for couples to pick and choose certain traits they want in their baby?
Will in vitro fertilisation be used to choose only embryos that don’t have any genetic disorders?
What does sexual reproduction mean?
Sexual reproduction means that two parents are needed to form the new offspring.
What do hormone imbalances affect and in what?
Hormone imbalances that affect the reproduction of gametes can occur in both males and females.
How are hormone imbalances treated?
The problem of hormone imbalances is often treated with hormone replacement therapy (HRT).
What happens during HRT?
During HRT the person is given doses of whatever hormone is missing or in short supply in their body.
Explain the symptoms, causes and treatments of 2 medical issues that can arise in the human reproductive system.
Medical issue > symptoms > possible causes > possible treatments
Medical issue > symptoms > possible causes > possible treatments
Absence of ovulation: No eggs released from ovary > Low hormone levels > HRT
Low sperm count: Insufficient sperm for fertilisation to occur > low hormone levels, alcohol abuse, smoking > HRT, stop drinking/smoking.
Any method used to assist couples to become pregnant is known as what?
Any method used to assist couples to become pregnant is known as assisted human reproduction (AHR).
What can be very costly with AHR?
AHR is usually very expensive, particularly IVF treatment.
Hormone replacement therapy can also be costly.
