IGCSE Biology - Reproduction (Human)

Fertilization

When male and female gametes fuse to produce a zygote that undergoes cell division.

Sperm

Male gametes that are made in the testes all the time after puberty.

Ova

Female gametes that are produced every 28 days from one of the two ovaries from puberty until menopause.

Semen

The liquid substance that is ejaculated from the penis into the vagina during sexual intercourse.

Bladder

The muscular bag that stores urine.

Vas deferens

Long, narrow tube that carries sperm from epididymis to ejaculatory duct.

Seminal vesicle

This sac makes the semen for sperm to swim in.

Scrotum

The sac that hangs behind the penis and holds the testicles.

Testicles

The two small, egg-shaped glands that produce sperm.

Urethra

The tube which carries sperm through the penis during ejaculation; urine also exits the body through the urethra.

Ovaries

Produces ova and female sex hormones.

Endometrium

Thickens during the menstrual cycle in preparation for a possible baby.

Cervix

The opening of the uterus.

Vagina

Where sperm are deposited; unfertilized eggs exit through here during the menstrual cycle.

Uterus

The organ where an embryo grows.

Fallopian tube

A muscular tube that carries the ovum from the ovary to the uterus.

Oestrogen

This hormone causes the lining of the uterus to thicken and stimulates the release of LH (luteinizing hormone) which releases the ova.

Progesterone

When the egg is released, this hormone is released from the corpus lutem, where it is produced, and maintains the lining of the womb. The lining comes away when levels of this hormone fall.

Placenta

Lets the blood of the embryo and mother get very close and exchange food, oxygen and waste.

Amniotic membrane

This membrane is full of amniotic fluid which protects the embryo against knocks and bumps.

Oestrogen

This hormone causes secondary sexual characteristics in females: breasts develop in preparation for breastfeeding,

hips grow in preparation for childbirth, the menstrual cycle begins, hair grows (pubic regions, armpits) and acne may form

Testosterone

This hormone causes secondary sexual characteristics in males: voice breaks, sperm production begins, muscles and penis grow, hair grows (pubic regions, armpits, chest), and acne may form