1. Chapter 46:
Animal Reproduction

2. Figure 46.8 Insect reproductive anatomy
Ovary 1
Accessory gland 4
Ejaculatory duct 1
Testis
Oviduct 2
Spermatheca 5
Penis 2
Vas deferens
Vagina 3 3
Seminal vesicle
Accessory gland
(a) Male honeybee. Sperm form in the testes, pass through the sperm duct (vas deferens), and are stored in the seminal vesicle. The male ejaculates sperm along with fluid from the accessory glands. (Males of some species of insects and other arthropods have appendages called claspers that grasp the female during copulation.)
(b) Female honeybee. Eggs develop in the ovaries and then pass through the oviducts and into the vagina. A pair of accessory glands (only one is shown) add protective secretions to the eggs in the vagina. After mating, sperm are stored in the spermatheca, a sac connected to the vagina by a short duct.

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

4. 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

5. 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

6. 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

7. 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

8. 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)

9. 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

10. 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