2. Reproduction: Mitosis vs. Meiosis
Cells and tissues get
damaged or simply wear
out
Damaged or worn-out
cells and tissues must be
repaired or replaced
Asexual reproduction,
or mitosis, is the process
by which cells make exact
copies of themselves,
and is essential to
maintain a healthy body
3. Meiosis to Carry On the Species
Ultimately, cellular
reproduction needed for
complicated process by
which humans produce
new humans: sexual
reproduction
Without this ability, the
human species would
die out and journey for
human race would end
4. Reproduction: Mitosis vs. Meiosis
Cellular reproduction:
process of making new
cell
Asexual reproduction:
cells make identical
copies of themselves
without involvement of
another cell
Most cells can
reproduce themselves
asexually, whether
animal cells, plant cells, or
bacteria
5. Reproduction: Mitosis vs. Meiosis
Includes how cell is to
function within body and
blueprints for
reproduction
All chromosomes must
be copied before cell can
divide
Mitosis is only way
eukaryotic cells can
reproduce asexually
Any time cells must be
replaced, mitosis is
method used to replace
them
6. Reproduction: Mitosis vs. Meiosis
Without mitosis, body
would not be able to
grow or replace old
or damaged cells
Chief difference:
meiosis pairs
homologous (similar
in size, shape and
genetic content)one
from each human
7. Meiosis to Carry On the Species
Sexual
reproduction: to
perpetuate
species
Union of cell from
one organism with
cell from another
organism of same
species
8. Gametes- Sperm and Egg
In animals, females produce
eggs (ova), males produce
sperm, and special cells
called gametes
Gametes produced by
meiosis (reduction division)
because daughter cells
produced at end of
meiosis have half as
many chromosomes as
original mother cell
9. Meiosis to Carry on the Species
Daughter cells must have
half as many
chromosomes because
they will fuse together
during sexual reproduction
In humans, total number is
46 chromosomes; there
are 23 pairs of
chromosomes
Each pair of chromosomes
consists of one
chromosome from your
father and one from your
mother
10. 23rd Chromosome-Determines
Sex of the Child
23rd “pair” is sex
chromosome, so
named because they
determine sex of baby
XX is female, XY is
male; father
determines sex of
baby because mother
can only contribute X
chromosomes
11. The Human Life Cycle-Egg and
Sperm
Eggs and sperm, with
only half as many
chromosomes as
other cells, are
produced by
meiosis in
specialized organs
known as gonads
Testes (male);
ovaries (female)
12. The Human Life Cycle
During sexual reproduction, gametes unite and
combine their genetic material; union is called
fertilization
Fertilized egg (zygote) has 46 chromosomes
Zygote reproduces millions of times via mitosis and
develops within female to change from embryo to
fetus
14. Human Reproductive System
Reproductive organs called
genitalia and are divided into:
Primary genitalia:
gonads that produce
gametes
Secondary genitalia:
other structures that aid
in reproductive process
15. Human Reproductive System
o Primary genitalia are ovaries
o Secondary genitalia are
Fallopian tubes, uterus, vagina,
external genitalia called vulva
o Ovaries are paired
structures, about 3 cm long,
in peritoneal cavity, with one
ovary on either side of
uterus
16. Figure 17-3
Internal female reproductive organs
o Ovaries covered by
fibrous capsule called
tunica albuginea.
Interior has cortex,
which contains eggs
o Uterine tubes
(oviducts or Fallopian
tubes) are
passageways for eggs
to get to uterus
18. The Uterus
Thick-walled and
pear-shaped;
found in pelvic
cavity posterior
and superior to
urinary bladder
and anterior to
rectum
19. The Uterus
Consists of three layers:
Perimetrium:
outermost layer,
visceral peritoneum
Myometrium: consists
of smooth muscle
Endometrium: inner
lining is mucosa layer
of columnar
epithelium and
secretory cells with
two divisions
Basal layer: responsible for
regenerating uterine lining each
month
Functional layer: sheds about every
28 days when woman has her period
20. The Vagina
Smooth muscle tube with
mucous membrane lining;
10 cm long, running from
uterus to outside of body
Purpose is to receive penis
during intercourse and
allow for passage of
menstrual fluid out of
uterus
Also called birth canal,
since another function is to
allow movement of baby
out of uterus during
childbirth
21. The Vagina
External opening may be
covered by a
perforated membrane
(hymen)
Torn hymen once
thought to “prove” that
woman had intercourse
Many hymens are highly
perforated and easily
ruptured by day-today activities such as
riding a bike or jogging
22. The Cervical Canal and Cervix
Cervix is valve
like portion of
uterus that
protrudes into
vagina, while
cervical canal
connects with
vagina
23. Screening for Cervical Cancer
A PAP smear is
done during a pelvic
exam that involves
scraping cervical
cells, checking for
cancer
Cervical cancer is
now known to be a
sexually transmitted
disease caused by
specific strains of
HPV (human
papilloma virus)
24. Figure 17-5
The external female genitalia
o Collectively known as
vulva; complex and
important part of
reproduction
o Vulva surrounded by two
prominences called labia
majora; rounded fat
deposits that surround
entrance to vagina
o Labia majora meet
anteriorly to form mons
pubis, covered by
pubic hair
25. Figure 17-6
The mammary glands.
o Another set of external
accessory sexual organs
in female; milk
production glands
housed in breasts
o In young children,
mammary tissue virtually
identical in boys and
girls
o At puberty, estrogen
and progesterone
stimulate breast
development in girls
27. The Menstrual Cycle
Takes approximately
28 days; involves
ovaries, uterus,
pituitary gland, and
hypothalamus
Ovarian cycle involves
monthly maturation
and release of eggs
from ovary
Uterine cycle consists of
monthly buildup,
decaying, and
shedding of uterine
lining
28. The Menstrual Cycle
Cycles begin in woman’s
teen years, during
puberty with menarche;
end during her 40s or 50s in
menopause
Goal is to release egg for
fertilization and prepare
uterus to receive and
nourish fertilized egg
should pregnancy result
If pregnancy does not
result, uterine lining will
shed and cycle will begin
again
29. The Menstrual Cycle
Begins with first
day of
menses; time
period when
uterine lining is
shed
Menstruation:
term referring to
actual
shedding of
endometrium
30. The Menstrual Cycle
Menses can last 4 to
5 days; can be
longer or shorter in
different women;
can vary month to
month in same
woman
31. The Menstrual Cycle
The smooth
muscle layer of
the uterus
responsible for
muscular
contractions with
childbirth and the
cramping that
occurs with
menstruation
32. The Follicular Phase & Luteal Phase
From day 1–14 oocyte (egg
cell) undergoing number of
developmental changes
getting ready for
ovulation on day 14 with
increase in ESTROGEN
Ovulation: release of
mature egg from ovary
followed by the increase of
PROGESTERONE on days
15-28 or second half of
the cycle
33. Menstrual Cycle
If oocyte fertilized by sperm,
it will implant in thickened
endometrium
If egg doesn’t implant within
few days, endometrium will
begin to decay and
menstruation will occur
within two weeks
34. Hormonal Control-Ovarian &
Pituitary
FOUR HORMONES
control menstrual cycle:
Ovarian hormones: estrogen
and progesterone
Pituitary hormones
luteinizing hormone (LH) and
follicle-stimulation hormone
(FSH)
35. Menstrual Cycle
It is the CORPUS
LUTEUM (what remains
of the ruptured
follicle after ovulation)
that secretes
progesterone to
maintain the
endometrial lining of
the uterus to support
the fertilized egg
36. Menstrual Cycle
Decreasing progesterone
cause degeneration of
endometrium, followed
by menstruation
Decreased progesterone
also releases
hypothalamus and
pituitary from inhibition
FSH and LH levels rise
and cycle begins again
37. Menstrual Cycle
EXTRA CREDIT Essay on
the Final Exam will have
questions on the ovarian
hormones involved in
menstrual cycle, the
pituitary hormones
involved and the timing of
the menstruation as well
as the hormone measured
in pregnancy test
TO PREPARE: Watch the
video on “Ovulation and
the Menstrual Cycle” and
use your book, Page 494
38. Menstrual Cycle
Premenstrual Syndrome is
characterized by
predictable cognitive,
physical, emotional and
behavioral symptoms
associated with the luteal
phase (approximately 5
days before menses)
No screening test to
detect
Treatment depends on
severity
39. Menstrual Cycle
Increased stress and/or
illness can affect the onset
or frequency of menstrual
cycle due to it’s affect on the
hypothalamus — an area
of the brain that controls the
hormones that regulate the
menstrual cycle.
Ovulation and menstruation
may stop as a result.
40. Pregnancy and HCG Levels
If pregnancy does result,
implanted fertilized egg
secretes hormone called
human chorionic
gonadotropin (HCG)
HCG stimulates corpus
luteum to keep
secreting progesterone
and a little estrogen to
maintain the uterine lining
41. Pregnancy and HCG Levels
This is the hormone
that is measured in
the blood or urine
when a pregnancy
test is done
43. Figure 17-9
Oxytocin and breast feeding
At the end of
pregnancy, oxytocin
is responsible for
causing uterine
contractions to
begin labor as well as
stimulating the
release of milk from
the breasts
45. Figure 17-10
Male reproductive anatomy
Testes (gonads):
primary genitalia,
producing male
gamete, and sperm
Unlike female,
primary male
genitalia are
external
46. Figure 17-10
Male reproductive anatomy
Accessory genitalia:
•penis (spermdelivery organ),
•epididymis,
•vas deferens, and
urethra (sperm
ducts)
Several accessory
glands: prostate
gland, seminal
vesicles, and
bulbourethral glands
47. The Testes (Testicles)
Paired organs
suspended in sac
called scrotum,
hanging on either
side of penis
During embryonic
development, testes
formed in abdomen;
in last three
months of
development,
migrate into
scrotum
48. Epididymis-Ducts of Male
Several ducts in male
reproductive system:
•Epididymis is commashaped duct on
posterior and lateral
part of testes
•Sperm mature here
Epididymis
49. Vas Deferens
Runs from
epididymis as pair
of tubes, one on
each side, into
abdominal wall
and pelvic cavity,
medially over
urethra and along
posterior bladder
wall
Vas deferens
50. Seminal Vesicle
Seminal vesicle
then lead to
ejaculatory
duct, which then
passes through
prostate gland
and empties into
urethra
Seminal vesicle
52. Hormonal Control of Male
Reproduction
Testosterone most
important sex
hormone
Before birth, secretion
of HCG by placenta
stimulates
embryonic testes to
secrete
testosterone,
masculinizing fetus
53. Hormonal Control of Male
Reproduction
At puberty, two
hormonal changes occur
that signal beginnings of
maturity
Testosterone
secretion by testes
increases
Change in
relationship
between
testosterone and
GnRH, LH, and FSH
54. Hormonal Control of Male
Reproduction
Testosterone secretion at
puberty responsible for
obvious physical
changes of male
secondary sexual
characteristic:
Body, facial, pubic hair
growth
Deepening of voice
Increased muscle and
bone mass
55. Hormonal Control of Male
Reproduction
LH and FSH affect males
exactly as they do
females
Stimulate gamete
development
Controlled same way
in males as in
females
GnRH released
from
hypothalamus,
which stimulates LH
and FSH secretion
from pituitary
56. Ejaculation-Expulsion of Sperm
• In order for sperm
to leave body
during erection,
ejaculation,
expulsion of
semen (sperm and
assorted
chemicals), must
occur
• First sperm are
made in testes
57. Ejaculation-Expulsion of Sperm
Smooth muscle
contracts throughout
ducts and glands of
male reproductive
system and propels
sperm from
epididymis into
vas deferens, and
into pelvic cavity
As sperm passes
seminal vesicles,
sugar and chemicals
added
58. Ejaculation-Expulsion of Sperm
Sperm and
chemicals enter
ejaculatory
duct, passing
though
prostate
gland, where
fluid is added,
liquefying
semen
59. Ejaculation-Expulsion of Sperm
Semen then passes
by bulbourethral
glands; adds
mucus to semen
and protects
sperm from acid
environment of
vagina by secretion
of alkaline substance
Semen enters
urethra and
carried outside
body
60. Fertilization of Human Ovum
Female reproductive
system not
hospitable to
sperm and many
will not survive
journey
If there is an egg
waiting to be
fertilized, sperm
will find egg and
attempt to
penetrate it for
fertilization
61. Fertilization of Human Ovum
New research suggests
that egg is not
passive participant
in fertilization, but
may actually engulf
sperm and even
choose which to allow
inside
Only one sperm will
fertilize egg
62. FINAL EXAM Chapters 15-17
Final Exam Study
Guide for
Chapters 15-17
available in FILES
on CANVAS
