16. Human Reproductive System_Notes.docx

Lower Secondary Science Secondary 2 Express / Normal (Academic) Name: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ ( ) Class: \_\_\_\_\_ Date: \_\_\_\_\_\_\_\_\_\_\_\_\_\_ **Chapter 16: Human Sexual Reproduction System NotesCore Ideas** (a) recognise that the union of the nuclei of an egg...

Lower Secondary Science Secondary 2 Express / Normal (Academic) Name: \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ ( ) Class: \_\_\_\_\_ Date: \_\_\_\_\_\_\_\_\_\_\_\_\_\_ **Chapter 16: Human Sexual Reproduction System NotesCore Ideas** (a) recognise that the union of the nuclei of an egg and a sperm (inputs of a system) forms a fertilised egg which develops into a new individual (output of a system) (b) recognise that the sexual reproductive system facilitates heredity (the passing down of genetic material from one generation to the next) (c) \*recognise that a new individual formed through sexual reproduction receives a unique combination of genetic information from the mother (via the egg) and the father (via the sperm), resulting in similarities and differences between individuals and their parents, as well as among siblings (d) state some of the physical changes that occur during puberty and early adolescence as a result of the effect of hormones on other systems (Note: Details of the hormonal system are not required) (e) describe briefly how the parts of the human male and female reproductive systems are involved in fertilisation (f) describe how parts of the female reproductive system are involved in the menstrual cycle (g) outline how temporary and permanent birth control methods prevent conception by disrupting certain processes and/or the functions of certain organs in the reproductive system (h) state the harmful consequences of sexually transmitted infections (STIs) like syphilis, gonorrhoea and AIDS (i) state that some bacterial STIs can be cured by antibiotics, but not viral STIs **Practices** \(j) evaluate the consequences and issues relating to abortion and pre-marital sex **Values, Ethics, and Attitudes** (k) show an awareness that drug abuse (e.g., smoking, alcohol consumption and substance abuse) can have negative effects on the foetus (l) \*suggest reasons for the world's growing human population (e.g., advances in medicine, improved sanitation) **\*Optional for NA**. 1 ***16.1 What is the Function of the Human Sexual Reproductive System?* Sexual Reproduction** Many organisms reproduce [sexually]. This means their young are formed when the [nuclei of two sex cells join together]. The sex cells in humans are an [egg] cell and a [sperm] cell. These two cells are produced by different parts of the male and female reproductive systems.  The fusion of sex cells is called [fertilisation]. When an egg cell is fertilised, it develops into an embryo and develops into a new individual. This new individual contains the [genetic material (DNA)] from both its parents. **Heredity** The [passing down of genetic material] from one generation to the next during sexual reproduction is called heredity. **Family Resemblance & Variations (Optional for NA)** Children [inherit traits or chacteristics] from their parents. Children are not identical to their parents and possess a mix of traits from both their parents. During sexual reproduction, the individual [receives genetic material from the mother via the egg,] [and from the father via a sperm]. [Inheriting any trait is a random process]. An offspring can inherit any possible combination of traits from its parents. This explains why an individual is different from their parents and even their siblings. The genetic traits that are passed down [can be desirable, undesirable or neutral] to the next generation. Therefore, certain disorders or diseases such as sickle cell anaemia, or cystic fibrosis can be passed down from parent to offspring.. 2 ***16.2 How do the Parts of Each Reproductive System Work Together?* Puberty** Period when an adolescent becomes capable of reproducing and experiences rapid growth and development ▪ Sex and growth hormones cause changes to other body systems such as the skeletal and muscular systems o Boys will have heavier bones and an increase in muscle growth o Girls will experience an increase in the amount of fat tissues at the breasts, hips and pubic region +-----------------------------------+-----------------------------------+ | Boys | Girls | +===================================+===================================+ | Height and weight increases | | | | | | Armpit hair growth | | | | | | Pubic hair growth | | +-----------------------------------+-----------------------------------+ | Facial hair growth | Breasts begin to develop and | | | uterus enlarges | | Voice-box enlarges and voice | | | deepens Muscle strength | Hips become broader and rounder | | increases | Maturation of eggs and | | | menstruation begins | | Penis and testes increase in | | | size Production of sperms and | | | ejaculation occurs | | +-----------------------------------+-----------------------------------+. 3 **Human Reproductive Systems Male Reproductive System** kidney  bladder sperm duct testis male sex glands urethra penis sperm duct penis urethra bladder male sex glands ^scrotum^ scrotum testis [Diagram showing frontal view and side view of male reproductive system ] +-----------------------------------+-----------------------------------+ | Structure | Function | +===================================+===================================+ | Scrotums | ▪ Holds the testes outside body | | | | | (singular: scrotum) | | +-----------------------------------+-----------------------------------+ | Testes | ▪ Produce sperm & male hormones | | | | | (singular: testis) | | +-----------------------------------+-----------------------------------+ | Male sex glands | ▪ Secrete fluid containing | | | nutrients and enzymes | | | | | | o Fluid provides sperms with | | | energy to move | +-----------------------------------+-----------------------------------+ | Urethra | ▪ Tube that passes through the | | | centre of the penis, from bladder | | | to outside body | | | | | | ▪ During sexual intercourse, | | | sperms pass from testes into | | | sperm ducts to urethra to the | | | external environment | | | | | | ▪ Carries urine and semen | +-----------------------------------+-----------------------------------+ | Penis | ▪ Contains numerous blood | | | capillaries which fills with | | | blood during sexual intercourse | | | to allow the penis to become | | | erect | | | | | | ▪ Sperms are ejaculated through | | | penis during intercourse | +-----------------------------------+-----------------------------------+ | Sperm duct | ▪ Muscular tube that carries | | | sperms from testis to urethra | +-----------------------------------+-----------------------------------+ Structure of sperm head middle piece tail [Diagram of a sperm ]. 4 **Female Reproductive System** ovary fallopian tube  uterus cervix vagina [Diagram showing frontal view of female reproductive system ] +-----------------------------------+-----------------------------------+ | Structure | Function | +===================================+===================================+ | Ovaries | ▪ Produces eggs and female sex | | | hormones | | (singular: | | | | ▪ One of the ovaries produces an | | ovary) | egg every month | +-----------------------------------+-----------------------------------+ | Fallopian tube/ Oviduct | ▪ Narrow muscular tube connecting | | | ovary to the uterus ▪ Walls of | | | oviduct contract to push egg | | | toward uterus | +-----------------------------------+-----------------------------------+ | Uterus | ▪ Pear shaped organ with thick | | | muscular walls | | | | | | ▪ Inner surface is covered by | | | uterine lining | +-----------------------------------+-----------------------------------+ | Cervix | Circular ring of muscle at the | | | lower end of the uterus | +-----------------------------------+-----------------------------------+ | Vagina | ▪ Muscular tube which joins | | | cervix to the outside of the body | | | ▪ Site of sperm deposition during | | | intercourse | +-----------------------------------+-----------------------------------+ Structure of egg  [Diagram of an egg] ▪ Contains nucleus which contains hereditary information to be pass down from one generation to the next. 5 **Menstruation** ▪ Menstruation is the monthly discharge of blood, uterine lining and unfertilised egg from the uterus via vagina ▪ Typically 28 days cycle +-----------------------+-----------------------+-----------------------+ | Process | Day | Description | +=======================+=======================+=======================+ | Menstruation | 1 to 5 | If a sperm does not | | | | fertilise an egg, | | | | uterine lining breaks | | | | down and menstruation | | | | begins. | | | | | | | | Discharge of blood, | | | | uterine lining and | | | | unfertilised egg | | | | through the vagina. | +-----------------------+-----------------------+-----------------------+ | Repair of uterine | 6 to 10 | Uterine lining is | | lining | | repaired. | +-----------------------+-----------------------+-----------------------+ | Further thickening of | 11 to 17 | Uterine lining grows | | uterine lining | | thicker & becomes | | | | rich with blood | | | | capillaries. | +-----------------------+-----------------------+-----------------------+ | Ovulation | 14 days before [next | Release of egg from | | | ] | one ovary into | | | | fallopian tube. | | | menstruation | | | | | | | | **(Day 14 in a 28-day | | | | cycle)** | | +-----------------------+-----------------------+-----------------------+ | Fertile period | 4 days before and 1 | If sexual intercourse | | | day after ovulation | takes place within | | | | this period, it is | | | **(Day 10 to 15 in a | likely to result in | | | 28-day cycle)** | pregnancy. | +-----------------------+-----------------------+-----------------------+ | Maintenance of | 18 to 28 | Uterine lining | | | | remains thick to | | thickness of the | | supply embryo with | | | | nutrients and oxygen | | uterine lining | | for growth. | +-----------------------+-----------------------+-----------------------+. 6 **Fertilisation and pregnancy** ▪ During sexual intercourse, sperms are deposited in the vagina and move up the uterus to the oviduct to the egg ▪ If an egg is present, fertilisation may occur o Fertilisation is the **[fusion]** of the **[nucleus]** of the sperm and **[nucleus]** of an egg ▪ Fertilised egg then divides repeatedly to form an embryo ▪ Embryo moves into uterus and implants in the uterine lining. The woman is now pregnant. ▪ Embryo develops into a foetus ▪ At the end of the 9 months of pregnancy, muscles of uterus contract to push the foetus out; cervix enlarges to allow foetus to pass through during birth The diagram summaries the process of fertilisation and heredity in sexual reproduction. ^name\ of\ cell\ --\ egg^ name of cell -- sperm nucleus nucleus name of cell -- fertilised egg (zygote) (formed by process called fertilisation, involving the fusion of the nucleus of the egg and nucleus of the sperm) \`. 7 ***16.3 How Can the Function of the Human Reproductive System be Disrupted?* Substance abuse** Smoking, consumption of alcohol and abuse of controlled drugs are harmful. During pregnancy, it also harms the foetus. Effects of Substance Abuse: babies may be born premature babies may be born with low birth weight smoking may affect the development of the foetus' heart, lungs and brain alcohol consumption and abuse of drugs can lead to physical, intellectual and behavioural challenges in the child. **Birth Control** refers to the methods and devices used to prevent pregnancies. **Temporary methods** +-----------------------+-----------------------+-----------------------+ | Methods that prevent | | | | **[fertilisation]{.un | | | | derline}** | | | +=======================+=======================+=======================+ | Rhythm Method | Sexual intercourse |  | | (Calendar method) | fertile period of the | | | | menstrual cycle. | | | | (avoid fertile period | | | | of menstrual cycle). | | +-----------------------+-----------------------+-----------------------+ | Condom | The condom collects | | | | sperms so that the | | | | sperms are not | | | | released into a | | | | woman's vagina. | | +-----------------------+-----------------------+-----------------------+ | Diaphragm | The diaphragm blocks |  | | | so that sperms cannot | | | | pass from the vagina | | | | into the uterus. | | +-----------------------+-----------------------+-----------------------+ | Spermicide | chemicals used to | | | | kill sperms | | +-----------------------+-----------------------+-----------------------+. 8 +-----------------------+-----------------------+-----------------------+ | Methods that prevent | | | | **[ovulation]{.underl | | | | ine}** | | | +=======================+=======================+=======================+ | Contraceptive Pills / | Contains hormones |  | | Birth Control Pills | | | | | prevent release of | | | | egg from ovary | | +-----------------------+-----------------------+-----------------------+ | Methods that prevent | | | | **[implantation]{.und | | | | erline}** | | | +-----------------------+-----------------------+-----------------------+ | Intra-uterine device | Coil which is | | | (IUD) | inserted into the | | | | uterus to prevent the | | | | | | | | implantation of the | | | | embryo into uterine | | | | wall | | +-----------------------+-----------------------+-----------------------+ **Permanent methods** **Surgical method** Also known as sterilisation Most reliable form of contraception Usually irreversible a\) **Male sterilisation: Vasectomy** Sperm ducts are cut and tied, preventing sperms from reaching penis. Sexual characteristics are not affected: Testes continue to secrete male hormones.  b\) **Female sterilisation: Tubal ligation** Both oviducts are cut and tied, preventing the sperms from reaching the oviduct to fertilise the egg.. 9 **Abortion (Not a form of birth control)** Abortion is the deliberate termination of a pregnancy Foetus is removed using medication or surgical means Complications that might arise from abortion: 1\) damage to the uterus a\. resulting in bleeding b\. resulting in infertility (inability to conceive) 2\) developing an infection after the procedure ***16.4 How Do Medical Advancements Impact Human Reproduction and Survival?* Sexually Transmitted Infections (STIs)** +-------------+-------------+-------------+-------------+-------------+ | **STI & | **Signs &** | **Mode of** | **Treatment | **Preventio | | causes** | | | methods** | n** | | | **Symptoms* | **transmiss | | | | | * | ion** | | **methods** | +=============+=============+=============+=============+=============+ | 1) | ▪ Can | ▪ Sexual | ▪ Can be | ▪ Avoid | | Gonorrhea | become | | | having | | | | intercourse | cured by | multiple | | ▪ *caused | infertile | | | sexual | | by* | | (exchange | antibiotics | | | | ▪ Babies | of | | partners | | *bacteria* | can | | | | | | | body fluids | | ▪ Avoid | | | become | of | | sharing | | | blind if | | | instruments | | | | reproductiv | | | | | bacteria | e | | that can | | | enters | | | break | | | | system) | | | | | eye during | | | the skin | | | birth | ▪ | | and | | | | Contaminate | | | | | | d | | be | | | | blood | | | | | | | | contaminate | | | | ▪ | | d | | | | Childbirth | | | | | | | | with blood, | | | | ▪ | | like | | | | Breast-feed | | | | | | ing | | razors, | | | | | | | | | | | | toothbrushe | | | | | | s | | | | | | | | | | | | ▪ Ensure | | | | | | that | | | | | | | | | | | | needles | | | | | | used | | | | | | | | | | | | for ear | | | | | | | | | | | | piercing, | | | | | | | | | | | | acupuncture | | | | | | | | | | | | are | | | | | | properly | | | | | | | | | | | | sterilised | | | | | | or | | | | | | | | | | | | insist on | | | | | | | | | | | | disposables | | | | | | | | | | | | ▪ Donated | | | | | | blood | | | | | | should be | | | | | | | | | | | | screened | | | | | | for | | | | | | | | | | | | HIV before | | | | | | use | +-------------+-------------+-------------+-------------+-------------+ | 2) Syphilis | ▪ May | | | | | | become | | | | | ▪ *caused | blind ▪ | | | | | by* | Inability | | | | | | to move | | | | | *bacteria* | parts of | | | | | | the body ▪ | | | | | | Can lead to | | | | | | heart | | | | | | failure, | | | | | | insanity | | | | | | | | | | | | and death | | | | | | if left | | | | | | | | | | | | untreated | | | | +-------------+-------------+-------------+-------------+-------------+ | 3) Acquired | ▪ During | | ▪ No cure, | | | | late stage | | | | | Immunodefic | of HIV | | drugs only | | | iency | infection, | | present to | | | Syndrome | person | | | | | (AIDS) | suffers | | alleviate | | | | | | | | | ▪ *caused | from weight | | symptoms | | | by Human | loss, lung | | | | | Immunodefic | infections | | and | | | iency | | | | | | Virus | and brain | | control | | | which* | | | | | | | infections | | progress | | | *attacks | | | | | | immune* | | | of | | | | | | | | | *system* | | | infection | | +-------------+-------------+-------------+-------------+-------------+. 10 **Growth in World Population (Optional for NA)** The world population grew greatly in the twentieth century due to the following factors: **Medical Advancements** New drugs, vaccines and medical treatments helped people to survive and live longer lives. New diagnostic techniques allowed faster and more accurate diagnosis for patients. Inventions like pacemakers, defibrillators and lung machines helped patients that would have died otherwise. **Increased Food Production** Overall food supply increased, which allowed less people to die from hunger These factors increased overall food supply: Advances in technology allowed plants to be grown in poor soil. Farm animals had more food and were kept healthier with new drugs. More efficient breeding methods allowed more abundant and cheaper farm food. **Improved Transportation** Improvement in technology allowed goods such as food and medicine to be supplied to more regions in a shorter time. **Improved Sanitation** Better sanitation and waste management reduced the spread of deadly diseases such as cholera and typhoid through human waste containing the bacteria.. 11