Unit 16: Human Reproductive System Flashcards
Sexual Reproduction
4pt
- Requires two parents, a male and a female, and involves special cells called gametes (sex cells)
- Occurs in multicellular organisms
- The new organisms are not identical to the parents
- inherit characteristics from both parents
Asexual Reproduction
4pt
- Production of new organisms from a single parent
- Usually occurs in unicellular organisms such as the amoeba
- New cells identical to the parent
- A single amoeba reproduces itself by dividing into two new cells (division)
what is puberty
3pt
- Puberty is a period where the body undergoes various physical changes and matures sexually
- Puberty is necessary for the human body to prepare itself for sexual reproduction
- Puberty begins when sex hormones are produced in the reproductive organs
- eg oestrogen in ovaries and testosterone in testis
Physical Changes during Puberty
Changes in Female only
4pt
Ovaries release Ova (Egg)
Menstruation Begins
Breasts begins to develop
Hips become broader and rounder
Physical Changes during Puberty
Changes in both Male and Female
4pt
Sex Hormones released
Hair grows in armpits and around reproductive organs
Sex organs become larger
Height and weight increase
Physical Changes during Puberty
Changes in Male only
4pt
Testis produce Sperms
Voice Deepens
Hair grows on face and body
Muscle strength increase
Sex Glands
3pt
- Produce fluids in which the sperms swim in
- The mixture of sperms and fluid is called semen
- Semen contains nutrients and lubricating effect to help the sperm move better
Scrotum
2pt
- A bag of skin which holds the testes outside the body
- The testes are outside the body because it requires a lower body temperature to produce healthy sperms (enrichment)
Testis (plural: Testes)
3pt
- The testes produce male sex cells called sperms.
- Each sperm is very small and shaped like a tadpole.
- The sperm is the smallest cell in the human body
Sperm Duct
1pt
- Carries sperms from the testis to the penis
Urethra
1pt
- A tube which carries sperms and urine at different times
Penis
1pt
- The organ from which sperm-carrying fluid leaves the body and is deposited in the body of the female
Ovary (Plural: Ovaries)
4pt
- The ovaries produce eggs or ova (singular: ovum).
- Normally, one ovum is produced (released) each month.
- The ovum is the female sex cell.
- It is the largest cell in the human body (and is the size of this full stop).
Oviduct (fallopian tube)
2pt
- A tube which carries ova released from the ovary to the uterus
- It waits for the sperm to reach for a few days before getting passed out of the system
Uterus
1pt
- A pear-shaped structure where an embryo grows and develops
Cervix
1pt
- The narrow opening of the uterus; it widens during the birth of a baby
Vagina
2pt
- A tube which links the uterus to the outside of the body
- Organ in which sperms are deposited and the passage though which a baby is born
Uterine Lining
1pt
- To provide nutrients to embryo if fertilised or sheds if egg is unfertilised and repairs itself every menstrual cycle
Human Sexual Reproduction
3pt
- The fusion of sex cells is called fertilization
- 3 stages in human reproduction on how life is formed: Fertilisation, Pregnancy, Birth
- Nucleus of the cell contains the genetic information (DNA) in chromosomes
Sperm
Movement ability
Location of Nucleus
No. of Chromosomes
No. of cells
Can move on its own with the help of the tail
Nucleus located in the head segment
Nucleus containing 23 chromosomes
About 2 million of sperms per ejaculation
Egg (Ovum)
Movement ability
Location of Nucleus
No. of Chromosomes
No. of cells
Cannot move on its own
Nucleus located in the cell
Nucleus containing 23 chromosomes
Only one egg released in every 28-day cycle
Heredity
6pt
- The process of passing down the genetic material from one generation to the next during sexual reproduction is called heredity
- The nucleus in each human cell contains 46 chromosomes (23 pairs)
- The chromosomes carry genes containing information that controls the growth and appearance of a child
- Unlike ordinary cells, the ovum and the sperm have 23 single chromosomes each
- During fertilisation, the 23 single chromosomes in each nucleus come together to form 23 pairs of chromosomes
- Thus, a child receives half its genetic information from the mother (through the ovum) and half from the father (through the sperm)
Menstrual Cycle
Day
1 to 5
Events
4pt
- The thickened lining of the uterus is shed if fertilisation does not take place
- It is discharged through the vagina together with blood
- Menstruation occurs
- Unfertilised egg, uterine lining and blood is discharged
Menstrual Cycle
Day 6 to 9
Events
2pt
- The lining on the wall of the uterus thickens with many blood vessels formed in it.
- This process prepares the uterus for the implantation of the embryo if fertilisation occurs
Menstrual Cycle
day 10 to 15
2pt
- One ovary will release an egg into the oviduct on around day 14. This is known as ovulation.
- A woman is most fertile during this period and having sexual intercourse is likely to lead to pregnancy
Menstrual Cycle
day 16 to 28
events
1pt
- The uterine lining will continue to thicken. If no fertilisation occurs, menstruation will occur again after day 28
Disruptions to the Human Reproductive System
3 ways
- The function of the human reproductive system can be disrupted by:
1. Substance abuse - Taking drugs without doctors’ prescription (e.g Accutane – to control acne)
2. Birth control methods (Contraception) - E.g. abstinence, rhythm method and condoms
3. Abortion - The deliberate termination of a pregnancy
Family Planning
3pt
Family Planning
* Often, married couples plan when to have a baby and how many to have. This is called family planning
* If a couple does not want to have a baby, they need to practise some form of birth control to prevent pregnancy
* Birth control methods can be classified into two main groups — temporary and permanent methods
Birth Control Methods
Temporary - 7pt
Permanent - 2pt
Temporary
1. Rhythm Method
2. Abstinence
3. Spermicide
4. Condoms
5. Pills (Birth control pills)
6. IUD (intra-uterine device)
7. Diaphragm
Permanent
1. Tubal ligation
2. Vasectomy
Temporary Birth Control methods
3pt
- Artificial means - Use of chemicals or mechanical devices to prevent pregnancies and work by disrupting processes or functions
- Intra-uterine devices prevent the embryo from being implanted in the wall of the uterus
- STDs are transferred via body fluids
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Abstinence
Not having sexual intercourse at all Natural
Fertilisation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Rhythm Method
refraining from sexual intercourse during ovulation / fertile period (usually days 11-17, ±4 days from day 14 which is ovulation day)
Natural
Fertilisation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Condom
A thin rubber tube that is put on the erect penis before intercourse
Prevents sperms from being deposited in the vagina
Mechanical
Fertilisation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Diaphragm
A rubber or plastic barrier that is fitted by a doctor over the cervix
Prevents sperms from entering the uterus
Mechanical
Fertilisation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Intra-uterine device (IUD)
A plastic or metal coil or loop inserted by a doctor or trained person (metal coil destroys ovum)
Prevents the fertilised ovum from being implanted in the uterine wall
Mechanical
Implantation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Spermicide
Substance that kills sperms
Applied in the vagina before intercourse
May be in the form of creams, jellies, foam and tablets
Chemical
Fertilisation
Temporary Birth Control Method Description
Nature of Method
Mode of Prevention
Birth Control pills
Contain chemicals that mimic female hormones that prevent ovulation
Chemical
Ovulation
Permanent birth control methods
3pt
- These methods are carried out by a doctor to make a person incapable of reproducing. This is also known as sterilisation
- Sterilisation is irreversible
- Vasectomy for male sterilisation and Tubal Ligation for female sterilisation
Vasectomy – Male sterilisation
3pt
- The sperm ducts are cut and tied
- No sperm can be released through the penis
- Ejaculation is still possible but semen does not contain sperm
Tubal Ligation – Female sterilisation
3pt
- The oviducts are cut and tied
- The ova will not be able to reach the uterus
- As a result, sperm cannot reach the ova (fertilisation cannot occur)
Social and Moral issues relating to human reproduction
* Premarital sex – having sex before marriage
3pt
- Premarital sex – having sex before marriage
Problems relating to premarital sex - Unplanned pregnancies
- Abandoning of babies or giving them up for adoption
- Feelings of loss, grief, rejection and identity issues in abandoned or adopted babies
Social and Moral issues relating to human reproduction
* Abortion – the deliberate ending of a pregnancy
4pt
- Abortion – the deliberate ending of a pregnancy
Problems relating to abortion - Infections of the uterus and oviducts, leading to difficulty in getting pregnant in the future
- Accidental puncturing of the uterus, resulting in heavy bleeding
- Massive bleeding from the vagina may result in death
- Feelings of guilt and depression
Sexually Transmitted Diseases/Infections (STD/STI)
- STDs are transmitted via body fluids.
- There are 2 types of STI: Viral and Bacterial STIs.
- Bacteria STIs can be treated with antibiotics while Viral STIs cannot be treated with antibiotics.
How does medical advancement impact the human reproductive system and survival?
2pt
- Increase in food supply, the development of medicines, and improved sanitation, improved transportation
- This has resulted in more people being born each year than people dying, and increased lifespan
