Secondary 2 Science Chapter 8: Human Sexual Reproductive System

Vocabulary practice flashcards covering terms, organs, processes, contraception methods, STIs, and key concepts from Chapter 8: Human Sexual Reproductive System.

Sexual Reproduction

The production of new organisms by combining genetic information from two individuals of different sexes through fertilisation.

Gamete

A specialised sex cell (such as a sperm cell or egg cell) containing half the normal number of chromosomes.

Fertilisation

The union of the nucleus of a male gamete (sperm) with the nucleus of a female gamete (egg) to form a fertilised egg.

Zygote

A fertilised egg cell formed by fertilisation that contains a full set of $46$ chromosomes ($23$ pairs in humans).

Embryo

A ball of cells formed through multiple cell divisions of a zygote that embeds into the uterine lining.

Foetus

The stage of prenatal development when major organs have formed from the embryo and continue to grow until birth.

Heredity

The passing down of genetic material (DNA) from one generation to the next during sexual reproduction.

Meiosis

A type of cell division that results in four daughter cells, each containing half the number of chromosomes of the parent cell.

Differentiation

The normal process by which a less specialised cell undergoes maturation to become more distinct in form and function.

CRISPR

Clustered Regularly Interspersed Short Palindromic Repeat; a gene editing technique used to artificially change the genetic material of an organism.

Fraternal Twins

Non-identical twins produced when two separate eggs are released at about the same time and fertilised by two different sperms.

Puberty

A period of active growth in adolescence when an individual becomes physically mature and capable of reproducing due to sex hormones.

Testis

Male reproductive organ (plural: testes) that produces sperms and male sex hormones such as testosterone.

Epididymis

Organ in the male reproductive system that stores inactive sperms from the testis before they are released into the sperm duct.

Scrotum

A pair of pouch-like sacs holding the testes outside the main body cavity to maintain them at a lower temperature for healthy sperm development.

Sperm Duct

The pathway through which sperms travel from the testes to the urethra.

Semen

A mixture of sperms and nutrient- and enzyme-rich fluids released by male sex glands (such as the prostate gland) that activate the sperms.

Urethra

A tube extending from the urinary bladder through the penis where urine and semen are passed out of the body.

Ejaculation

The process in which semen leaves the male reproductive system.

Penis

An erectile organ with spongy tissue filled with blood that enters the vagina during sexual intercourse to deposit sperm-containing semen.

Ovaries

Female reproductive organs that produce eggs/ova and female sex hormones such as oestrogen and progesterone.

Oviduct

A narrow muscular tube leading from the ovary to the uterus where fertilisation takes place.

Uterus

The female reproductive organ in which the foetus develops during pregnancy.

Uterine Lining

Soft inner lining of the uterus (endometrium) that thickens to prepare for embryo implantation and breaks down when fertilisation does not occur.

Cervix

A circular ring of muscles at the lower end of the uterus that contracts to retain the foetus during pregnancy and dilates during birth.

Vagina

The muscular passage where semen is deposited during sexual intercourse and through which birth occurs.

Sperm Cell Structure

Male reproductive cell about 60\n\mu m long, composed of a head (containing nucleus and enzyme-filled acrosome), middle piece (containing mitochondria), and tail/flagellum.

Ovum Structure

Spherical female reproductive cell (120\n\mu m to 150\n\mu m wide) consisting of a nucleus, large amount of cytoplasm, and a cell surface membrane surrounded by an outer membrane.

Acrosome

An enzyme-containing structure in the head of a sperm cell that releases enzymes to break down part of the egg membrane during fertilisation.

Implantation

The process where the embryo reaches the uterus and gets embedded in the thickened uterine lining.

Placenta

An organ formed after implantation that allows the exchange of substances between the mother and the developing foetus.

Umbilical Cord

A flexible structure that connects the foetus to the placenta.

Menstruation

The discharge of the broken-down uterine lining, blood vessels, and unfertilised egg through the vagina (Days $1$ to $5$ of the cycle).

Ovulation

The release of a mature egg from the ovary into the oviduct, typically occurring around Day $14$ of the menstrual cycle.

Fertile Period

The period during the menstrual cycle (typically Days $10$ to $15$) when having sexual intercourse is most likely to result in pregnancy.

Contraceptive Pills

A temporary birth control method containing female sex hormones taken daily to prevent ovulation.

Abstinence

A birth control method of refraining entirely from sexual intercourse to prevent pregnancy and STIs.

Vasectomy

A permanent surgical birth control method for males involving the cutting and tying of the sperm ducts to prevent sperm release.

Tubal Ligation

A permanent surgical birth control method for females involving the cutting and tying of both oviducts to prevent sperms from reaching the egg.

Diaphragm

A dome-shaped rubber cap positioned over the cervix to prevent sperms from entering the uterus and oviducts.

Condom

A thin rubber sheath covering the penis that blocks sperm entry into the uterus and protects against sexually transmitted infections.

Spermicide

A chemical placed in the vagina to kill sperms, typically used in combination with a condom or diaphragm.

Intra-uterine Device (IUD)

A plastic or metal device inserted into the uterus by a doctor to immobilise/kill sperm and prevent embryo implantation.

Sexually Transmitted Infection (STI)

An infection passed from person to person through sexual contact via blood, semen, or vaginal fluid.

AIDS

Acquired Immunodeficiency Syndrome; an incurable STI caused by HIV that destroys white blood cells and severely impairs immune function.

Syphilis

A bacterial STI causing initial painless sores and rashes, which can lead to organ damage or death if untreated, but is curable with antibiotics.

Gonorrhoea

A bacterial STI causing burning sensations during urination, which can lead to infertility, but is curable with antibiotics.

Pre-marital Sex

Sexual intercourse before marriage, which carries risks of unwanted pregnancies and sexually transmitted infections.

Abortion

The medical or surgical termination of a pregnancy by removing the embryo or foetus from the uterus.