Grade 12 Life Science: Human Reproduction

Flashcards covering human reproduction concepts for Grade 12 Life Sciences.

What is puberty?

Time period during which sex organs develop and gametes are produced; sexual maturity occurs between 11-15 for boys and 10-14 for girls.

List some male secondary sexual characteristics.

Increased muscle mass, development of a deeper voice, enlargement of sexual organs, production of sperm, increased production of sweat, increase in facial and body hair, skin becomes more oily, and behavioral changes.

What is puberty?

Refers to the period during which sexual maturity occurs.

What structures comprise the male reproductive system?

Testes, epididymis, vas deferens, urethra, seminal vesicles, prostate gland, Cowper's gland, and penis.

Describe the testes.

Lie outside the abdominal cavity to maintain a temperature 2-3°C lower than body temperature for optimal sperm production; covered by the scrotum.

What are the functions of the testes?

Produce and release sperm cells and produce testosterone.

What is the epididymis?

The seminiferous tubules join to form this coiled tube behind the testes where spermatozoa are stored and mature.

What is the function of the vas deferens?

Its function is to transport sperm from the epididymis to the urethra using peristalsis.

What is the function of the urethra?

Transports urine and semen to the exterior (but not at the same time).

What is the function of the seminal vesicle secretion?

The main food source for sperm.

What are the functions of the prostate fluid?

Ensures maximum motility of sperm and protects sperm against the low pH of the urethra and vagina.

What are the functions of the Cowper's gland secretions?

Contributes to greater motility of sperm, clears the urethra of urine residue, and lubricates the head of the penis.

What is the function of the penis?

To transfer semen to the female.

What is an erection?

hardening of the penis.

What is ejaculation?

Release of semen.

List some female secondary sexual characteristics.

Increase in fat deposited under the skin, widening of hips, development of breasts, increase in height, development of egg cells in the ovaries, start of menstruation, growth of body hair, skin becomes more oily, and behavioral changes.

What structures comprise the female reproductive system?

A pair of ovaries, the fallopian tube, the uterus and cervix, vagina and vulva and the clitoris.

What is the function of germinal epithelium?

Produces follicles, which then produce egg cells or ova by oogenesis; also produce oestrogen and progesterone.

What is the function of the fallopian tubes?

Transport the egg cell/zygote from the ovary to the uterus and is the site of fertilization.

What is the function of the uterus?

Care of the embryo.

What is the function of the vagina?

The penis releases sperm into the vagina, and it forms the birth canal to deliver a baby.

What is the structure of the vagina and vulva?

Muscular tube that opens to the exterior through the vulva with an acidic environment to prevent diseases.

What is the function of the clitoris?

Sexual excitement.

What is Gametogenesis?

Refers to the process by which gametes are produced from the germinal epithelium of the male and female sex organs.

What is Spermatogenesis?

The process by which spermatozoa are produced from the germinal epithelium of the testes.

What is Oogenesis?

The process during which ova are produced from the germinal epithelium of the ovary.

What are the parts of a sperm head?

Nucleus with 23 chromosomes and the acrosome, which has enzymes for penetrating the ovum.

What does a sperm midpiece have?

A large number of mitochondria that provide energy for movement of the sperm.

What is the structure of an Ovum?

Haploid nucleus with 23 chromosomes, cytoplasm known as the yolk, plasma membrane, yolk membrane, zona pellucida, and corona radiata.

What is the menstrual cycle?

Changes that occur in the ovary and uterus of a female over a period of 28 days.

What does the ovarian cycle describe?

The changes that occur within the ovary during the development of the egg cell within the Graafian follicle.

What controls the ovarian cycle?

Controlled by FSH and LH.

What are the three important changes that are happening in the ovarian cycle?

The development of the primary follicles into the Graafian follicle, the rupturing of the follicle and release of the immature ovum during ovulation and the formation of the corpus luteum.

What does FSH control?

FSH controls the maturing of follicles into the Graafian follicle.

What does LH cause to happen to the Graafian follicle.

LH causes the Graafian follicle to rupture releasing egg cell.

What is the corpus luteum?

The remnants of the Graafian follicle turns into this, which then produces progesterone.

What does the uterine cycle refer to?

The changes that occur in the walls of the uterus as it thickens until menstruation occurs.

What are the hormones of the uterine cycle for?

To develop the endometrium for implantation of the embryo with Oestrogen to thicken it, increase the blood vessels and it create more glands, while Progesterone helps to maintains the endometrium.

What is menstruation?

The breakdown of the upper endometrial layers that is discharged together with blood.

What does FSH do?

Secreted from the pituitary gland to stimulate the development of the primary follicles into Graafian follicles.

What does Oestrogen do?

Secreted from the Graafian follicle to stimulate the development of endometrial tissue and inhibit the release of FSH.

What does LH do?

Secreted from the pituitary gland to stimulates the process of ovulation.

What does Progesterone do?

Produced by the corpus luteum, it plays a role in maintaining of the endometrium and inhibits the release of FSH and LH.

What is the negative feedback mechanism?

The increase in one hormone results in the decrease or inhibition of another hormone.

What happens during copulation?

Sperm cells are deposited into the vagina with an erect penis, then The spermatozoa swim up the vagina through the cervix, through the uterus, into the fallopian tube.

What happens during fertilisation?

The nucleus of the sperm cell (n) fuses with the nucleus of the mature ovum (n) forming a diploid cell together called a zygote and with 46 chromosomes with genetic material from both parents.

What is a foetus?

Name given to the embryo from week 9.

What is the placenta?

A temporary vascular tissue made up of the chorionic villi and the uterine tissue, that never mix fetal blood with maternal blood but transfer via diffusion.

What are the functions of the placenta?

Nutrition, excretion, gaseous exchange, acts as a microfilter, and endocrine function.

What are the umblical arteries and veins?

Carries deoxygenated blood with nitrogenous waste from the foetus to the placenta and Carries oxygenated blood rich in nutrients from the placenta to the foetus.

What are Amniotic fluid functions?

Provides watery medium for foetus to move freely in and develop and Protects foetus from shocks, dehydration and temp changes.

What is the Amnion?

A membrane found on the inside of the chorion.

What is the chorion?

Outmost membrane around the foetus.

What is Foetal alcohol syndrome?

Occurs when the foetus is exposed to high levels of alcohol during pregnancy, which affects the growth and development of the foetus.

What happens during kraam/labour?

The foetus starts to turn head-down in the last few weeks of pregnancy which stimulates the secretion of oxytocin from the pituitary gland, which stimulates the muscles of the uterine wall to contract = contractions.

What does it mean about a term: Pregnancy or gestation period?

A period during which the embryo develops within the uterus until the baby is born.

What happens during the First stage – Labour?

The contractions cause the cervix to dilate to about 10cm, the amniotic membrane ruptures and releases the amniotic fluid, and the Eerste fase – Kraam.

What happens during the Second stage – Expulsion of baby?

Cervix is completely dilated and the baby passes through the cervical opening and vagina to the exterior and the umbilical cord is clamped and cut

What happens during the Third stage – Release of afterbirth?

Omtrent 20-30 min after birth, contractions start again to push out the placenta, membranes and umbilical cord

What hormones affect the mammary glands?

Oestrogen and progesterone stimulate milk glands, duct development and growth during pregnancy and Oxytocin causes the release of milk from the glands

What is laktasie/milk production?

Milk production, and Estrogeen and progesteroon stimuleer die ontwikkeling en groei van melkkliere en buise tydens swangerskap. Then Oksitosien veroorsaak die vrystelling van melk vanaf die kliere.

What is Contraceptives?

The voluntary regulation of the number of births by preventing pregnancy, with Natural - withdrawal, Barrier - condom, Chemical - pills and injection, Surgical - tying.

What is withdrawal from sex?

The penis is withdrawn from the vagina before ejaculation which can be hard to control

What is ritme method for contraceptives?

The menstrual cycle is used, Seksuele omgang word vermy ‘n paar dae voor en na ovulasie, but this can be hard to avoid days.

How doe Barrier methods work for contraption?

Prevents the sperms from getting into the vagina. If this is used correctly, it can be a reliable method.

How doe Contraceptive pills work for contraption?

This have a chemical substance that kills sperm cells on contact in creams and tablets.

How does a vasectomy help with contraceptives?

The vas deferens are cut and tied from both testes, so Sperm cells are still produced but can’t move past this point.

What is Infertility?

The inability to achieve pregnancy after one year of unprotected sex for couples.

How does Fertility enhancers help with Infertility?

FSH and LH is given to stimulate ovulation. increases chances of multiple births, because multiple ova are released.

How does In vitro fertilisation (IVF) help with Infertility?

Fertilisation occurs outside of the body cause the womans fallopian tubes are blocked, but still produce normal ova.

How does Gamete-Intra-Fallopian-Transfer (GIFT) help with Infertility?

Fertilisation occurs in the fallopian tube, its More natural process Cheaper than IVF and helps woth male infertility.

What is Surrogacy?

When a woman carries and gives birth to a baby on behalf of a couple, as surrogaatskap is gedoen when there are no other options.

What is Syphilis?

caused by a bacterium – Treponema pallidum, this infects the mucous membranes of the sex organs, caused by - Sexual contact with an infected person of Mother infecting baby.

What is Gonorrhoea?

a bacterium – Neisseria gonorrhoeae this affects the urinary and reproductive systems, caused by - Sexual contact with an infected person, mother of baby has