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Chapters 46 and 47 Campbell 9th
Oviduct
Ovary
Uterus
(Urinary bladder)
(Pubic bone)
(Rectum)
Cervix
Vagina
Urethra
Body
Clitoris
Glans
Prepuce
Labia minora
Labia majora
Major vestibular
(Bartholin’s) gland
Vaginal opening
Ovaries
Oviduct
Follicles
Corpus luteum
Uterus
Uterine wall
Endometrium
Cervix
Vagina
(Urinary bladder)
Seminal vesicle
(Urinary duct)
(Rectum)
Vas deferens
Ejaculatory duct
Prostate gland
Bulbourethral gland
(Pubic bone)
Vas deferens
Epididymis
Testis
Scrotum
Erectile
tissue
Urethra
Glans
Prepuce
Penis



Gametogenesis, the production of gametes,
differs in male and female, reflecting the distinct
structure and function of their gametes
Sperm are small and motile and must pass from
male to female
Eggs are larger and carry out their function within
the female
© 2011 Pearson Education, Inc.



Spermatogenesis, the development of sperm, is
continuous and prolific (millions of sperm are
produced per day; each sperm takes about 7
weeks to develop
Oogenesis, the development of a mature egg, is
a prolonged process
Immature eggs form in the female embryo but do
not complete their development until years or
decades later
© 2011 Pearson Education, Inc.

Spermatogenesis differs from oogenesis in three
ways
◦ All four products of meiosis develop into sperm
while only one of the four becomes an egg
◦ Spermatogenesis occurs throughout adolescence
and adulthood
◦ Sperm are produced continuously without the
prolonged interruptions in oogenesis
© 2011 Pearson Education, Inc.
Epididymis
Seminiferous tubule
Testis
Primordial germ cell in embryo
Cross section of
seminiferous tubule
Mitotic divisions
Spermatogonial
stem cell
2n
Mitotic divisions
Sertoli cell
nucleus
Spermatogonium
2n
Mitotic divisions
Primary spermatocyte
2n
Meiosis I
Secondary spermatocyte
Lumen of
seminiferous tubule
Neck
Tail
Plasma
membrane
n
n
Meiosis II
Spermatids
(two stages)
Early
spermatid
n
n
n
n
Differentiation
(Sertoli cells
provide nutrients)
Midpiece Head
Acrosome
Nucleus
Mitochondria
Sperm cell
n
n
n
n
Primordial germ cell in embryo
Mitotic divisions
2n
Spermatogonial stem cell
Mitotic divisions
Spermatogonium
2n
Mitotic divisions
Primary spermatocyte
2n
Meiosis I
Secondary spermatocyte
n
n
Meiosis II
Early
spermatid
Sperm cell
n
n
n
n
Differentiation
(Sertoli cells
provide nutrients)
n
n
n
n
Primary
oocyte
within
follicle
Ovary
Primordial germ cell
Growing
follicle
In embryo
Mitotic divisions
2n
Oogonium
Mitotic divisions
Primary oocyte
(present at birth), arrested
in prophase of meiosis I
2n
First
polar
body
Completion of meiosis I
and onset of meiosis II
n
n
Secondary oocyte,
arrested at metaphase of
meiosis II
Ovulation, sperm entry
Mature follicle
Ruptured
follicle
Ovulated
secondary
oocyte
Completion of meiosis II
Corpus luteum
Second
polar
n
body
n
Fertilized egg
Degenerating
corpus luteum
Primordial germ cell
Mitotic divisions
2n
In embryo
Oogonium
Mitotic divisions
Primary oocyte
(present at birth), arrested
in prophase of meiosis I
2n
First
polar
body
Completion of meiosis I
and onset of meiosis II
n
n
Secondary oocyte,
arrested at metaphase of
meiosis II
Ovulation, sperm entry
Completion of meiosis II
Second
polar
n
body
n
Fertilized egg

Stop Here and Do the Handout first



Human reproduction is coordinated by hormones
from the hypothalamus, anterior pituitary, and
gonads
Gonadotropin-releasing hormone (GnRH) is
secreted by the hypothalamus and directs the
release of FSH and LH from the anterior pituitary
FSH and LH regulate processes in the gonads
and the production of sex hormones
© 2011 Pearson Education, Inc.



In females, the secretion of hormones and the
reproductive events they regulate are cyclic
Prior to ovulation, the endometrium thickens with
blood vessels in preparation for embryo
implantation
If an embryo does not implant in the endometrium,
the endometrium is shed in a process called
menstruation
© 2011 Pearson Education, Inc.
(a)
Control by hypothalamus
GnRH
1
Anterior pituitary
2
(b)
Inhibited by combination of
estradiol and progesterone

Hypothalamus
FSH

Stimulated by high levels
of estradiol

Inhibited by low levels of
estradiol
LH
Pituitary gonadotropins
in blood
6
LH
FSH
3
(c)
Ovarian cycle
7
Growing follicle
Maturing
follicle
8
Follicular phase
Corpus
luteum
Ovulation
Ovarian hormones
in blood
Degenerating
corpus luteum
Luteal phase
Estradiol secreted
by growing follicle in
increasing amounts
4
(d)
LH surge triggers
ovulation
FSH and LH stimulate
follicle to grow
Progesterone and
estradiol secreted
by corpus luteum
Peak causes
LH surge
(see 6 )
5
10
9
Estradiol
Progesterone
Progesterone and estradiol promote thickening
of endometrium
Estradiol level
very low
Uterine (menstrual) cycle
(e)
Endometrium
Days
Menstrual flow phase Proliferative phase
0
5
10
14 15
Secretory phase
20
25
28

Hypothalamus
GnRH


FSH
LH
Leydig cells
Sertoli cells
Inhibin
Spermatogenesis
Testis
Testosterone
Negative feedback
Negative feedback
Anterior pituitary



During its first 2 to 4 weeks, the embryo obtains
nutrients directly from the endometrium
Meanwhile, the outer layer of the blastocyst,
called the trophoblast, mingles with the
endometrium and eventually forms the placenta
Blood from the embryo travels to the placenta
through arteries of the umbilical cord and returns
via the umbilical vein
© 2011 Pearson Education, Inc.
Maternal
arteries
Placenta
Umbilical
cord
Maternal
veins
Maternal
portion of
placenta
Chorionic
villus,
containing
fetal
capillaries
Fetal
portion of
placenta
(chorion)
Maternal
blood pool
Uterus
Fetal arteriole
Fetal venule
Umbilical cord
Umbilical
arteries
Umbilical vein
from
ovaries
Oxytocin

from fetus
and mother’s
posterior pituitary
Activates oxytocin
receptors on uterus
Stimulates uterus
to contract
Stimulates
placenta to make
Prostaglandins
Stimulate more
contractions
of uterus

Positive feedback
Estradiol
Placenta
Umbilical cord
Uterus
Cervix
1 Dilation of the cervix
2 Expulsion: delivery of the infant
Uterus
Placenta
(detaching)
Umbilical cord
3 Delivery of the placenta
The importance of cell-cell communication.
Zygote
2-cell
stage
forming
Gray crescent
0.25 mm
8-cell stage (viewed
from the animal pole)
4-cell
stage
forming
8-cell
stage
Animal
pole
0.25 mm
Blastula (at least 128 cells)
Vegetal pole
Blastula
(cross
section)
Blastocoel




Gastrula
Morula
Blastula
Zygote
ZYGOTE
MORULA
SOLID BALL
BLASTULA
(BLASTOCYST IN
MAMMALS)
GASTRULA
EMBRYO


After cleavage, the rate of cell division slows and
the normal cell cycle is restored
Morphogenesis, the process by which cells
occupy their appropriate locations, involves
◦ Gastrulation, the movement of cells from the
blastula surface to the interior of the embryo
◦ Organogenesis, the formation of organs
© 2011 Pearson Education, Inc.

Gastrulation rearranges the cells of a blastula
into a three-layered embryo, called a gastrula
© 2011 Pearson Education, Inc.

The three layers produced by gastrulation are
called embryonic germ layers
◦ The ectoderm forms the outer layer
◦ The mesoderm partly fills the space between the
endoderm and ectoderm
◦ The endoderm lines the digestive tract

Each germ layer contributes to specific structures
in the adult animal
© 2011 Pearson Education, Inc.
ECTODERM (outer layer of embryo)
• Epidermis of skin and its derivatives (including sweat glands,
hair follicles)
• Nervous and sensory systems
• Pituitary gland, adrenal medulla
• Jaws and teeth
• Germ cells
MESODERM (middle layer of embryo)
• Skeletal and muscular systems
• Circulatory and lymphatic systems
• Excretory and reproductive systems (except germ cells)
• Dermis of skin
• Adrenal cortex
ENDODERM (inner layer of embryo)
• Epithelial lining of digestive tract and associated organs
(liver, pancreas)
• Epithelial lining of respiratory, excretory, and reproductive tracts
and ducts
• Thymus, thyroid, and parathyroid glands

The four extraembryonic membranes that form
around the embryo arise from the amniotic egg
◦
◦
◦
◦
The chorion functions in gas exchange
The amnion encloses the amniotic fluid
The yolk sac encloses the yolk
The allantois disposes of waste products and
contributes to gas exchange
© 2011 Pearson Education, Inc.


During organogenesis, various regions of the
germ layers develop into rudimentary organs
Early in vertebrate organogenesis, the notochord
forms from mesoderm, and the neural plate forms
from ectoderm
© 2011 Pearson Education, Inc.
Eye
Neural folds
Neural
fold
Tail bud
Neural plate
SEM
1 mm
Neural
fold
Somites
Neural tube
Neural
plate
Notochord
Neural
crest cells
1 mm
Neural
crest
cells
Coelom
Notochord
Somite
Ectoderm
Mesoderm
Endoderm
Neural
crest cells
Outer layer
of ectoderm
Archenteron
(a) Neural plate formation
Neural
tube
(b) Neural tube formation
Archenteron
(digestive
cavity)
(c) Somites


The neural plate soon curves inward, forming the
neural tube
The neural tube will become the central nervous
system (brain and spinal cord)
© 2011 Pearson Education, Inc.



Neural crest cells develop along the neural tube
of vertebrates and form various parts of the
embryo (nerves, parts of teeth, skull bones, and
so on)
Mesoderm lateral to the notochord forms blocks
called somites
Lateral to the somites, the mesoderm splits to
form the coelom (body cavity)
© 2011 Pearson Education, Inc.
Eye
SEM
Neural tube
Notochord
Coelom
Somites
Tail bud
1 mm
Neural
crest
cells
Somite
(c) Somites
Archenteron
(digestive
cavity)

The embryonic cells in a limb bud respond to
positional information indicating location along
three axes
◦ Proximal-distal axis
◦ Anterior-posterior axis
◦ Dorsal-ventral axis
© 2011 Pearson Education, Inc.
2
Digits
Anterior
3
4
Ventral
Distal
Proximal
Dorsal
Posterior
(b) Wing of chick embryo
EXPERIMENT
Anterior
New
ZPA
Donor
limb
bud
Host
limb
bud
ZPA
Posterior
RESULTS
4
What role does the zone of
polarizing activity (ZPA) play in
limb pattern formation in
vertebrates?
3
2
2
4
3



Sonic hedgehog is an inductive signal for limb
development
Hox genes also play roles during limb pattern
formation
Read Cell Fate Determination and Pattern
Formation 1039-1051
© 2011 Pearson Education, Inc.



Ciliary function is essential for proper specification
of cell fate in the human embryo
Motile cilia play roles in left-right specification
Monocilia (nonmotile cilia) play roles in normal
kidney development
◦ Almost every cell has one that acts as a transporter and
an antenna to receive info from other cells
© 2011 Pearson Education, Inc.
Lungs
Heart
Liver
Spleen
Stomach
Large intestine
Normal location
of internal organs
Location in
situs inversus
Epididymis
Seminiferous tubule
Testis
Primordial germ cell in embryo
Cross section of
seminiferous tubule
Mitotic divisions
Spermatogonial
stem cell
2n
Mitotic divisions
Sertoli cell
nucleus
Spermatogonium
2n
Mitotic divisions
Primary spermatocyte
2n
Meiosis I
Secondary spermatocyte
Lumen of
seminiferous tubule
Neck
Tail
Plasma
membrane
n
n
Meiosis II
Spermatids
(two stages)
Early
spermatid
n
n
n
n
Differentiation
(Sertoli cells
provide nutrients)
Midpiece Head
Acrosome
Nucleus
Mitochondria
Sperm cell
n
n
n
n
Primary
oocyte
within
follicle
Ovary
Primordial germ cell
Growing
follicle
In embryo
Mitotic divisions
2n
Oogonium
Mitotic divisions
Primary oocyte
(present at birth), arrested
in prophase of meiosis I
2n
First
polar
body
Completion of meiosis I
and onset of meiosis II
n
n
Secondary oocyte,
arrested at metaphase of
meiosis II
Ovulation, sperm entry
Mature follicle
Ruptured
follicle
Ovulated
secondary
oocyte
Completion of meiosis II
Corpus luteum
Second
polar
n
body
n
Fertilized egg
Degenerating
corpus luteum