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

2. Eggs mature and are released according to hormonal cycles.
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) regulate egg production.
meiosis produces 1 egg and 3 polar bodies
each egg has 23 chromosomes
Meiosis is started while in the womb (Prophase I,) put on hold
2 million cells ready to enter Meiosis after puberty starts
Every 28 days a cell (oocyte)
is released. Meiosis II complete
with fertilization.
potential
egg
first polar
body
second polar
ovum (egg)
Meiosis I
Completed
Meiosis II
only after
sperm
enters

3. FSH, LH, and estrogen stimulate the release of eggs.
follicle ruptures at ovulation
egg travels into fallopian tube (fertilized) 5-7 days
Release 400 to 500 eggs in a lifetime
ruptured follicle becomes corpus luteum (yellow body)
fallopian
tube
egg cell
egg released
corpus luteum
uterine wall
ovary
follicle
uterus
5 to 7 days to uterus

4. The menstrual cycle has three phases. Every 28 days
flow phase: endometrium sheds Day 1 to 5
blood, mucus, tissue fluid contractions = cramps
2. follicular phase: ovulation occurs Day 6 to 14

5. High levels of estrogen cause the endometrium to thicken.
High levels of LH, cause the follicle to rupture – releases the egg. Ovulation – about day 14
3. luteal phase: corpus luteum turns yellow Day 15 to 28
Corpus luteum breaks down and stops secreting hormones. Causes you to shed lining and flow begins.

6. 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, early onset menopause in 30’s can be caused by
hysterectomy, ovarian cancer,
hormonal issues

7. Testosterone, FSH, and LH stimulate sperm production.
Sperm production in the testes is controlled by hormones. Starts during puberty.
Testosterone, FSH, and LH stimulate sperm production.
one sex cell divides into four sperm
each sperm has 23 chromosomes
Males produce millions
of sperm a day
(approx. 85 million
per testicle)
Ejaculate about 300 million.
potential
sperm
4 sperm cells
Meiosis I
Meiosis II

8. Sperm cells fully mature in the epididymis.
head contains acrosome and nucleus (secretes enzymes to allow penetration of egg)
midpiece contains
mitochondria which makes ATP
tail (flagellum)
allows mobility
Sperm production declines
with age. defective
acrosome
head
midpiece
tail
mitochondria
nucleus with 23 chromosomes

9. 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

10. Multiple zygotes can result from fertilization.
identical twins from the
same egg/sperm
Also called “monozygotic”
fraternal twins from two separate eggs
Also called “Dizygotic”

11. Infertility makes reproduction difficult or impossible.
Sperm count is sometimes low due to toxins in the environment. 10% of U.S. couples or 6.1 million

12. IVF – Invitro Fertilization
Cost can be $12,000 and up per treatment.
1978 Louise Brown in England “1st test tube baby”

13. 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 (HPV) (cervical cancer – vaccine now available), and HIV

14. 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.