1. KEY CONCEPT Human reproductive processes depend on cycles of hormones.

2. Eggs mature and are released according to hormonal cycles.
potential
egg
first polar
body
second polar
ovum (egg)
Meiosis I
Completed
Meiosis II
only after
sperm
enters
Follicle-stimulating hormone (FSH) and lutenizing hormone (LH) regulate egg production.
meiosis produces eggs and polar bodies
each egg has 23 chromosomes
meiosis is completed at fertilization

3. FSH, LH, and estrogen stimulate the release of eggs.
follicle ruptures at ovulation
egg travels into fallopian tube
ruptured follicle becomes corpus luteum
fallopian
tube
egg cell
egg released
corpus luteum
uterine wall
ovary
follicle
uterus
5 to 7 days to uterus

4. Eggs mature and are released according to hormonal cycles.
The menstrual cycle has three phases.
flow phase: endometrium sheds
follicular phase: ovulation occurs
luteal phase: corpus luteum forms

5. The menstrual cycle stops at menopause.
cycle continues until a woman’s mid-40’s or 50’s
decline in hormone levels make cycles irregular
eventually, cycle stops altogether

6. Sperm production in the testes is controlled by hormones.
Testosterone, FSH, and LH stimulate sperm production.
one sex cell divides into four sperm
each sperm has 23 chromosomes
potential
sperm
4 sperm cells
Meiosis I
Meiosis II

7. Sperm cells fully mature in the epididymis. head contains acrosome
midpiece contains ATP
tail allows mobility
acrosome
head
midpiece
tail
mitochondria
nucleus with 23 chromosomes

8. Fertilization occurs when a sperm cell joins an egg cell.
Sperm penetrates an egg.
membrane keeps out other sperm
nucleus of sperm joins with egg
zygote formed

9. Multiple zygotes can result from fertilization.
identical twins from the same egg
fraternal twins from two separate eggs
Infertility makes reproduction difficult or impossible.

10. Sexually transmitted diseases affect fertility and overall health.
Sexually transmitted diseases (STDs) are passed from one person to another during sexual contact.
bacterial STDs include chlamydia, syphilis, gonorrhea
viral STDs include hepatitis B, genital herpes, human papillomavirus, and HIV
HIV

11. Viral STDs can be treated, but there is no cure for these diseases.
Bacterial STDs can be treated, and in many cases, cured with antibiotics
A parasite causes trichomoniasis, which can affect fertility.
Viral STDs can be treated, but there is no cure for these diseases.
STDs attack reproductive organs.
can cause infertility
untreated, some can be fatal
STDs can be avoided by abstinence or by using a condom.