Human Reproduction

Chapter 15 pp 485

Image credit: Dennis Kunkel

Male Anatomy

• Diagram 487 *****

• sex organs - testes

Testes• suspended in an external

sac - scrotum

• develop in the abdominal cavity and normally descend before birth

• temp 1.5 degrees lower

Sex cells - sperm

– swim by flagella– develop in

seminiferous tubules– stored in the epidiymis

Sperm con’t

– fluids produced by seminal vessicles, prostate gland and Cowper’s gland

– sperms + fluids = semen– travel from the epididymis to

urethra by vas deferens

Female Anatomy

• Diagram - page 490 *****

• Sex organs - ovaries

Ovaries

• In abdominal cavity

• groups of cells called follicles surround the egg and cause them to mature

• eggs travel from the ovary to the uterus through the oviducts (fallopian tubes)

Uterus• the uterus is a thick-walled muscular organ

in which the embryo develops (womb)

• the lining of the uterus is the endometrium

• the small opening at the lower end of the uterus is the cervix

• the cervix open to the vagina (birth canal)– note: the vagina is separate from the urethra

which excretes urine.

Fertilization:

• the union of a monoploid (haploid) egg and sperm forming a diploid zygote.

• Ovum can only be fertilized for about 18-24 hours after release

• sperm can survive for 3-5 days in a woman’s reproductive tract

Sequence of events in fertilization:

• Millions of sperm ejaculated into the vagina– as ovulation approaches cervical mucus

becomes watery allowing sperm to swim through

• If egg is fertilized, the implanted embryo produces Human Chorionic Gonadotrophin (HCG)

Sequence of events con’t

• HCG keeps the corpus luteum viable and allows continued production of progesterone.

– Progesterone production continues during pregnancy. 1st by CL, then by placenta.

– Progesterone inhibits FSH