Reproduction & Development RQ
1.
2.
3.
4.
5.
How many sperm can a mature man make in a
day?
Normally, how many mature eggs does a
female’s ovaries release over her life?
Through what process are gametes produced?
How many days after fertilization does the
baby blastocyst implant in the uterine wall?
What hormone does the embryo secrete
telling the mom’s body that she’s pregnant?
1. What are the two functions of
the male reproductive system?
1.
Production
of sperm
2. Delivery of
sperm to
the female
2. Where do sperm form and what are the
associated structures that help transport them?
• Sperm are made in the testes, which are housed by
the scrotum (which needs to stay cool for sperm production)
• Maturation of sperm after meiosis takes about 74
days (can make 300 million sperm every day)
• Epididymis – tubes where the sperm mature
• Vas deferens – sperm hang out here for 2 – 3 months
until they go to the urethra
• Seminal vesicles – secrete sugar-rich fluids for the
sperm for energy
• Prostate gland – secretes an alkaline fluid for the
sperm to move & survive
• Bulbourethral glands – secrete fluid that will
neutralize the female’s acidic environment
• ALL of this stuff together = semen
3. What happens to males during puberty?
Which hormones are specifically involved?
• Puberty = development of secondary sex
characteristics for sexual maturity
• The hypothalamus tells the pituitary to
secrete FSH and LH
– FSH will stimulate the production of sperm
cells
– LH will cause testosterone production
• Testosterone causes the growth & maintenance
of the sex organs, increases body hair, muscle
mass, and bone length, and deepens the voice 
4. Briefly describe the basic parts of
the female reproductive system.
• Functions – to produce eggs, to receive sperm,
and provide an environment for an embryo to
grow and develop
• Ovaries – allow for egg maturation
• Oviducts – tube for egg transport from the
ovary to the uterus
• Uterus – muscular organ where the baby
develops
• Cervix – narrow opening out the uterus into
the vagina (how the baby leaves) 
5. What happens to females during
puberty?
• The hypothalamus tells the pituitary to
secrete FSH and LH
– FSH stimulates the development of
follicles in the ovary
• A follicle is a group of epithelial cells that
surround a developing egg
– FSH causes the ovaries to release estrogen
• Estrogen causes the development of the
secondary sex characteristics in females
– Growth & maintenance of sex organs, growth of bones
& broadening of hips, body hair, fat deposits, and of
course the menstrual cycle 
6. How are eggs produced and released?
• When a female is born, she already has 2 million
potential eggs (primary oocytes) that have
stopped development at Prophase 1 of meiosis
– Most of these will break down, and at puberty the
ovaries only have @ 40,000
• Once a month several of these oocytes finish
meiosis and one egg ruptures out of the ovary
(ovulation) and passes into the oviduct
• About 400 eggs will be ovulated over the course
of a female’s life 
7. Briefly overview the flow, follicular,
and luteal phases of the menstrual cycle.
• Menstrual cycle – the series of changes
that occur to produce an egg and
prepare the uterus for a baby
• Repeats about once a month
• The corpus luteum (the part of the
follicle left from the egg being
released) secretes progesterone and
estrogen
– Progesterone maintains the lining of the
uterus in preparation for fertilized egg
implantation 
Continued… (using a 28 day cycle)
• Flow phase: Day 1-5
– The lining of the uterus (the endometrium) passes out
of the uterus through the cervix
– Contractions (cramps) help expel this stuff
• Follicular phase: Day 6 -14
– A developing primary oocyte secretes estrogen which
repairs the endometrium
– Estrogen levels peak, and LH causes ovulation
• Luteal phase: Day 15 – 28
– Named for the corpus luteum, which produces
estrogen and progesterone which thickens the
endometrial lining in prep for a zygote
– If no fertilization, back to the flow phase
– If implantation, endometrium begins nourishment 
8. Describe the process of fertilization
and implantation of an egg.
•
Released egg only stays alive for 24 hours
sperm (can live for 48 hours) must be present in the
oviduct in those first hours of ovulation for
fertilization to occur
•
300 to 500 million sperm are delivered, but
most die because of the acidic female
environment
–
•
Only a few hundred make it to the oviducts
Once a sperm gets to the egg, the egg
membrane changes electric charge, preventing
other sperm from fertilizing 
Continued…
• Egg nucleus + sperm nucleus = fertilized
egg (zygote)
• This zygote continues to the uterus,
undergoing mitosis as it goes
• After 6 days the zygote gets to the
uterus, and is now a hollow ball of cells
called a blastocyst
• When this attaches to the uterine
lining, it has “implanted”
9. List and describe the purpose of
the various embryonic membranes.
• Amnion: filled with amniotic fluid
– Shock absorber and temperature regulation
• Allantois: outgrowth of the digestive tract
– Blood vessels from this form the umbilical cord
which attaches the embryo to the uterine wall
• Chorion: outer membrane (surrounds amnion)
– 12 days after fertilization, chorionic villi begin
to grow into the uterine wall
– These two together form the placenta 
10. What structures allow the exchange
of materials between embryo and mom?
• The placenta deliver nutrients and carries
wastes away from the embryo
• Maternal blood vessels lie very close to the
embryo’s chorionic villi, allowing the diffusion
of these nutrients from mom and wastes from
baby across the placenta, which is connected
by the umbilical cord
• The waste products are excreted by the mom

11. How is a pregnancy maintained?
1. the developing zygote implants
2. it starts to secrete hCG (human
chorionic gonadotropin)…
3. which keeps the corpus luteum alive &
secreting progesterone…
4. which in turn maintains the
endometrial lining…
5. Until the 3rd or 4th month when the
placenta takes over 
12. What are the three different
processes of fetal development?
1. Growth – the actual increase in the
number of cells
2. Development – as these cells move and
arrange themselves into specific organs
3. Cellular differentiation – these cells
begin to perform specific tasks and
functions 
13. What happens during the first
trimester?
• A woman may not know she is pregnant
– The embryo is very sensitive to outside influences
• Drugs, environmental influences, malnourishment
• All the organ systems are formed by the 8th
week and is now a “fetus”
• At the end of this trimester, the baby is 28
grams (1 ounce) and 7.5cm (3 inches) from
head to butt
• Gender can be determined 
14. What happens during the second
trimester?
• 4th month is mostly limited to fetal body
growth
• 5th month mom can feel the fetus
• 6th month – eyes are open & lashes form
• Baby could possibly survive outside of the
womb with lots of medical intervention
• At the end of this trimester the baby is
650 grams (22 ounces) and 34cm (13
inches) long 
15. What happens during the third
trimester?
• Mass of fetus more than triples
• Kid is kicking, stretching, and moving
freely
• 8th month fat is deposited beneath the
skin in preparation for newborn insulation
• Baby’s systems are developed and can now
survive outside of the uterus
• By the end of this trimester, the baby is
on average 3300 grams (7 pounds) and
51cm (20 inches) long 
16. How can genetic disorders be predicted?
• Genetic counseling
– Will use medical histories of the parents
and families (pedigrees)
– Biochemical analyses of bloodwork
– Karyotypes
– DNA analysis 
17. What is the first stage of birth?
Describe how this happens. (Oww…)
• Dilation of the cervix
• Mild contractions are stimulated by the baby
pushing on the cervix
• This causes the release of the hormone oxytocin
• The contractions open (dilate) the cervix to allow
the baby to leave the uterus
– Dilation needs to get to 10cm (4 inches)
• Contractions get closer together and intensify
• Usually the amniotic sac will rupture (water
breaking) 
18. What happens during the
“expulsion” stage?
• The cervix is fully dilated
• The uterine contractions get so strong
that the baby is forced out of the
uterus, through the cervix, and into the
birth canal
• The mom’s abdominal muscles contract
with the uterus, pushing even stronger
• This stage USUALLY lasts 20 minutes
to an hour 
19. What is the placental stage of birth?
• Happens 10 – 15 minutes after the baby
is born
• The placenta separates from the
uterine wall and all membranes are
released from the mom’s body (afterbirth)
• Uterine muscles keep contracting,
constricting the uterine blood vessels to
mom doesn’t excessively bleed 
You might not want to see this…
20. Which hormone regulates
growth? How does it do this?
• Human growth hormone (hGH) is
secreted by the pituitary
• Acts on all cells, but mostly on the
skeleton and skeletal muscles
• Works by increasing the rate of protein
synthesis and fat metabolism
• Thyroxin, estrogen, and testosterone
help too 
21. What changes occur during infancy?
• First two years of life
• Lots of growth
– 2x birth weight by 5 months old
– 3x birth weight by 12 months old
– 4x birth weight by 24 months old
• Increase in physical coordination
– Learns to roll, sit, crawl, and walk
• Increase in mental development
– Begins to speak 
22. What happens as someone grows
from child to adult?
• Childhood- period from infancy to puberty
– Relatively steady growth
– Develops ability to reason and solve problems
• Adolescence- from puberty till max growth
– Growth spurts are typical
• 5-8cm in one year for some teenage boys
– Maximum height is achieved
• Determined by heredity, nutrition and environment
– Organs have reached maximum mass 
23. What kinds of stuff happens to
your body as you get older?
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Metabolism and digestion are slower
Skin loses some elasticity
Less pigment is produced (gray hair)
Bones become thinner and more brittle
Vertebral disks get compressed (shorter)
Vision and hearing diminish
Some people stay just as smart and
active as always! 