1. Chapter 46
Animal Reproduction

2. Figure 46.2 Asexual reproduction of a sea anemone (Anthopleura elegantissima)

3. Figure 46.3 Sexual behavior in parthenogenetic lizards
Time
Ovary size
Hormones
Behavior
Ovulation
Progesterone
Estrogen
Female- like
Male- like
(a) Both lizards in this photograph are C. uniparens females. The one on top is playing the role of a male. Every two or three weeks during the breeding season, individuals switch sex roles.
(b) The sexual behavior of C. uniparens is correlated with the cycle of ovulation mediated by sex hormones. As blood levels of estrogen rise, the ovaries grow, and the lizard behaves like a female. After ovulation, the estrogen level drops abruptly, and the progesterone level rises; these hormone levels correlate with male behavior.

4. Figure 46.1 Earthworms mating

5. Figure 46.5 External fertilization
Eggs

6. Figure 46.9 Reproductive anatomy of the human female
Glans
(Rectum)
Cervix
Vagina
Bartholin’s gland
Vaginal opening
Ovary
Oviduct
Labia majora
Labia minora
(Urinary bladder)
(Pubic bone)
Uterus
Urethra
Shaft
Prepuce
Clitoris

7. Vagina
Uterus
Cervix
Ovaries
Oviduct
Uterine wall
Endometrium
Follicles
Corpus luteum

8. Figure 46.13b Oogenesis

9. Figure 46.9x Ovary (left) and follicle (right)

10. Figure 46.10 Reproductive anatomy of the human male
Erectile tissue
of penis
Prostate gland
(Urinary bladder)
Bulbourethral gland
Vas deferens
Epididymis
Testis
Seminal
vesicle
(behind
bladder)
Urethra
Scrotum
Glans penis

11. Seminal vesicle
(Rectum)
Vas deferens
Ejaculatory duct
Prostate gland
Bulbourethral gland
(Urinary
bladder)
(Pubic bone)
Erectile
tissue of
penis
Urethra
Glans penis
Prepuce
Epididymis
Testis
Scrotum

13. Activity
Work in groups to tell me about the travel of a group of sperm to see the legendary follicle
Each member of your group will need to choose a role from below:
Leader, Reporter, Recorder, Noise monitor
Start out in the seminiferous tubules and work your way to the follicle
Be sure to include structure and function
This is a G rated classroom

14. Figure 46.12 Human Spermatogenesis
Epididymis
Seminiferous tubule
Testis
Cross section
of seminiferous
tubule
Sertoli cell
nucleus
Lumen of
Spermatogonium
Primary spermatocyte
(in prophase of meiosis I)
Secondary spermatocyte
Early
spermatids
Spermatids
(at two stages of
differentiation)
Differentiation
(Sertoli cells provide
nutrients)
Meiosis II
Meiosis I completed
Mitotic division,
producing large numbers
of spermatogonia
Sperm cells
Acrosome
Nucleus
Mitochondria
Neck
Tail
Plasma membrane
Head
Midpiece 2n n
Differentiation and
Onset of meiosis I

15. Figure 46.12 Structure of a human sperm cell

16. Figure 46.11 Human Oogenesis
Ovary
Primary germ cell in embryo
Differentiation
Oogonium
in ovary
Mitotic
division
Primary oocyte,
arrested in prophase
of meiosis I
(present at birth)
Completion of meiosis I
and onset of meiosis II
Primary
oocyte
within
follicle
Secondary oocyte,
arrested at meta-
phase of meiosis II
First
polar
body
Ovulation
Entry of
sperm triggers
completion of
meiosis II
Ovum
Growing
Mature follicle
Ruptured
Ovulated
secondary oocyte
Corpus luteum
Degenerating
corpus luteum 2n n
Second
polar
body

17. Figure 46.13 The reproductive cycle of the human female
Control by hypothalamus
Inhibited by combination of
estrogen and progesterone
Hypothalamus
Stimulated by high levels
of estrogen 1
GnRH
Anterior pituitary
Inhibited by low levels of
estrogen 2
FSH LH
(b)
Pituitary gonadotropins
in blood 6 LH
FSH
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation 3
(c)
Ovarian cycle 7 8
Growing follicle
Mature
follicle
Corpus
luteum
Degenerating
corpus luteum
Follicular phase
Ovulation
Luteal phase
Estrogen secreted
by growing follicle in
increasing amounts
Progesterone and
estrogen secreted
by corpus luteum 4
(d)
Ovarian hormones
in blood
Peak causes
LH surge 5 10
Estrogen
Progesterone 9
Estrogen level
very low
Progesterone and estro-
gen promote thickening
of endometrium
(e)
Uterine (menstrual) cycle
Endometrium
Menstrual flow phase
Proliferative phase
Secretory phase
Days 5 10 14 15 20 25 28

18. Activity
Work in pairs to compare the timing of the menstrual and ovarian cycles
Answer:
“Why does it make sense that each phase occurs when it does?”

19. Figure 46.14 Hormonal control of the testes
Stimuli from other
areas in the brain
Hypothalamus
GnRH from the
hypothalamus reg-
ulates FSH and LH
release from the
anterior pituitary.
FSH acts on the
Sertoli cells of the
seminiferous
tubules, promoting
spermatogenesis.
LH stimulates the
Leydig cells to make
testosterone, which
in turn stimulates
sperm production.
Anterior
pituitary
Negative
feedback
Leydig cells
make
testosterone
Primary and
secondary sex
characteristics
Sertoli cells
Spermatogenesis
Testis

20. From ovulation to implantation Implantation of blastocyst
Figure Formation of the zygote and early postfertilization events
Ovary
Uterus
Endometrium
From ovulation to implantation
Inner cell mass
Cavity
Blastocyst
Trophoblast
Ovulation releases a
secondary oocyte, which
enters the oviduct. 1
The blastocyst implants
in the endometrium
about 7 days after conception. 5
Cleavage continues.
By the time the embryo
reaches the uterus,
it is a ball of cells.
It floats in the uterus for
several days, nourished by
endometrial secretions. It
becomes a blastocyst. 4
Fertilization occurs. A sperm
enters the oocyte; meiosis of
the oocyte finishes; and the
nuclei of the ovum and sperm
fuse, producing a zygote. 2
Cleavage (cell division)
begins in the oviduct
as the embryo is moved
toward the uterus
by peristalsis and the
movements of cilia. 3
(a)
Implantation of blastocyst
(b)

21. Figure 46.16 Placental circulation
Umbilical cord
Chorionic villus
containing fetal
capillaries
Maternal blood
pools
Uterus
Fetal arteriole
Fetal venule
Maternal portion
of placenta
Fetal portion of
placenta (chorion)
Umbilical arteries
Umbilical vein
Maternal
arteries
veins

22. Figure 46.17 Human fetal development
5 weeks. Limb buds, eyes, the
heart, the liver, and rudiments
of all other organs have started
to develop in the embryo, which
is only about 1 cm long.
(a)
14 weeks. Growth and development
of the offspring, now called a fetus,
continue during the second trimester.
This fetus is about 6 cm long.
(b)
20 weeks. By the end of the
second trimester (at 24 weeks),
the fetus grows to about 30 cm
in length.
(c)

23. Figure 46.18 A model for the induction of labor
Estrogen
Oxytocin
from
ovaries
from fetus
and mother's
posterior pituitary
Induces oxytocin
receptors on uterus
Stimulates uterus
to contract
Stimulates
placenta to make
Prostaglandins
Stimulate more
contractions
of uterus
Positive feedback

24. Figure 46.19 The three stages of labor
Placenta
Umbilical
cord
Uterus
Cervix
Dilation of the cervix
Expulsion: delivery of the infant
(detaching)
Delivery of the placenta 1 2 3

25. Figure 46.20 Mechanisms of some contraceptive methods
Male
Female
Method
Event
Production of
viable sperm
viable oocytes
Vasectomy
Combination
birth control
pill (or injection,
patch, or
vaginal ring)
Sperm transport
down male
duct system
Ovulation
Abstinence
Condom
Coitus
interruptus
(very high
failure rate)
Sperm
deposited
in vagina
Capture of the
oocyte by the
oviduct
Tubal ligation
Spermicides;
diaphragm;
cervical cap;
progestin alone
(minipill, implant,
or injection)
movement
through
female
reproductive
tract
Transport
of oocyte in
Meeting of sperm and oocyte
in oviduct
Morning-after
pill (MAP)
Union of sperm and egg
Implantation of blastocyst
in properly prepared
endometrium
Birth
Progestin alone

26. Figure 46.21 Ultrasound image
Head
Body

27. 46.21 Ultrasound Of Fetus 1

28. 46.21 Ultrasound Of Fetus 2