3 (a) Reproduction in Humans

urethra

• tube which carries sperm through the penis during ejaculation

• urine also passes through the urethra to exit the body

erectile tissue

• swells when filled with blood

• to make the penis erect

testes

• where sperm is made

glands

• produce the liquid that’s added to sperm to make semen

sperm duct

• muscular tube that carries sperm from testes towards the urethra

scrotum

• hangs behind the penis and contains the testes

oviduct

• muscular tube that carries the ovum from the ovary to the uterus

uterus (womb)

• the organ where an embryo grows

ovary

• the organ that produces ova and sex hormones

endometrium (uterus lining)

• has a good blood supply for implantation of an embryo

cervix

neck of the uterus

vagina

where the sperm are deposited

oestrogen

• produced in the ovaries

• cause the lining of the uterus to grow

• stimulates the release of LH, which causes the release of an egg

progesterone

• produced in the ovaries by the remains of the follicle after ovulation

• maintains the lining of the uterus during the second half of the cycle

• when the level of progesterone falls, the lining breaks down

• inhibits the release of LH and FSH

role of the placenta in the nutrition of the developing embryo

• lets the blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste

oestrogen in women causes

• extra hair on underarms and pubic areas

• hips to widen

• development of breasts

• ovum release and start of periods

testosterone in men causes

• extra hair on face and body

• muscles to develop

• penis and testicles to enlarge

• sperm production

• deepening of voice

how is the developing embryo is protected by amniotic fluid

• the amnion membrane forms, which surrounds the embryo and is full of amniotic fluid

• amniotic fluid protects the embryo against knocks and bumps