Download Chapter 27 Student Notes

BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 27
Reproduction and Embryonic
Development
Module 27.1
From PowerPoint® Lectures for Biology: Concepts & Connections
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Mating Without Males
• There are no male desert-grassland whiptail
lizards
• The species reproduces without copulation or
fertilization
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• This photo shows a ritual behavior that primes
a female to lay eggs
– The female on top behaves much like a male in
other species of whiptail lizards
• Mating behavior
seems to be an
evolutionary
leftover
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• All animal species have three stages of
embryonic development
– __________________
– __________________
– ________________________________
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ASEXUAL AND SEXUAL REPRODUCTION
Sexual and asexual reproduction are both common
among animals
• Asexual reproduction
– __________
– __________
– __________, accompanied by
regeneration
– Development of an unfertilized
egg, known as _____________
– bees, wasps & some lizards
(turkeys)
Figure 27.1A
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__________– happens in fungi (mushrooms and molds),
Release specialized cells (NOT SEEDS) for reproduction.
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• Advantages of asexual reproduction
– A __________ individual reproduces
– Many offspring are produced __________
• Disadvantage of asexual reproduction
– Little or no __________ __________
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• Sexual reproduction
– The fusion of two haploid __________ from two parents to form
a diploid __________
– Each parent contributes one ____ of chromosomes to their
offspring to restore the chromosome number for the species
__________
Figure 27.1D
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• Advantages of sexual reproduction
– Increases genetic __________
– Enhances reproductive success in __________
environments
• Disadvantage of sexual reproduction
– Locating a __________
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• Rotifers can reproduce
both _______ and
_______
“Head”
Intestine
Ovary
Eggs
• Hermaphroditism
– A single individual
has both ______
and _____
reproductive systems
Figure 27.1B, C
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Where can fertilization happen?
• Externally
– Usually in a __________
environment (sperm swim)
• Advantages
– Produces large number of
__________
• Disadvantages
– Not all eggs are __________
– Not all offspring _________
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Where can fertilization happen?
• Internally
– Usually happens inside of
the __________.
• Advantages
– All eggs ________ (usually)
– Better __________ for
offspring (parental care)
• Disadvantages
– Parental __________
(time and energy)
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Where can development happen?
• Externally
– Happens outside of the female’s
__________
• Advantages
– ________ by parents (sometimes)
– Parental care by some birds and
some reptiles (__________)
• Disadvantages
– Little parental care in most ____,
________ and some ________.
– Exposure to __________
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Where can development happen?
• Internally
– Inside of females body
(__________ or __________)
• Advantages
– High __________ of offspring
– __________ of offspring
• Disadvantages
– High parental __________
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Ways to develop internally
• Usually mammals
• __________
– Egg layers
• Platypus
• Spiny Anteater
• __________
– Pouched mammal, some yolk
• Kangaroo, Opossum
• __________ __________
– Development using placenta and umbilical cord
• Humans, dogs, cats, deer
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Bladder
(excretory
system)
Seminal
vesicle
(behind
bladder)
Prostate gland
Bulbourethral
gland
Urethra
Erectile tissue
of penis
Vas deferens
Scrotum
Epididymis
Testis
Glans of
penis
Figure 27.3B
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Bladder
(excretory
system)
Seminal vesicle
Rectum
(digestive system)
Pubic bone
Vas deferens
Ejaculatory
duct
Erectile tissue
of penis
Prostate gland
Urethra
Vas deferens
Bulbourethral gland
Epididymis
Testis
Scrotum
Glans of penis
Prepuce
Figure 27.3A
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Reproductive anatomy of the human male
• Semen
– __________, which are expelled through the ducts during ejaculation
– __________ __________ that carry, nourish, and protect the sperm
• Testes
– Produce __________
– Located outside abdominal cavity within the __________
• Epididymis
– Place where sperm __________(16-18 hours), grow tails.
• Scrotum
– External pouch that holds testes, adjusts temp to ______ than
body temperature
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Reproductive anatomy of the human male
• Vas deferens
– Tube that carries semen (__________) from ________ to _______
• Seminal Vesicle
– Produces fluid rich in __________(energy)
• Prostate Gland
– Produces __________ (__________ pH)
• Bulbourethral (Cowper’s) Gland
– Produces __________ to allow sperm to swim through __________
• Urethra
– Tube that carries semen ____________________
• Penis
– Delivers semen into __________
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• __________ stimulate sperm production
– They also maintain homeostasis by a
__________ __________ mechanism that
inhibits the secretion of FSH (folliclestimulating hormone) and LH (luteinizing
hormone)
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The formation of sperm and ova requires meiosis
• Spermatogenesis
– Produces __________ in the male
• Oogenesis
– Produces __________ in the female
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• Spermatogenesis
– Increases genetic __________
– Primary __________ are produced throughout
a male’s reproductive years
– Diploid cells undergo meiosis to form four
__________ __________
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Epididymis
Testis
Scrotum
Penis
Diploid cell
Differentiation and
onset of MEIOSIS I
Testis
Seminiferous tubule
PRIMARY SPERMATOCYTE
MEIOSIS I completed
Cross section of
seminiferous
tubule
(in prophase of MEIOSIS I)
SECONDARY SPERMATOCYTE
(haploid; double chromatids)
MEIOSIS II
Developing sperm cells
(haploid; single chromatids)
Differentiation
SPERM CELLS
(haploid)
Center of
seminiferous
tubule
Figure 27.4A
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HUMAN REPRODUCTION
Reproductive anatomy of the human female
• Ovaries
– Contain
__________
that nurture
eggs
– Produce
____ __________
• Oviducts (fallopian
tubes)
– Convey eggs
to the __________
– Usual site of _________
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Ovaries
Oviduct
Corpus luteum Follicles
Uterus
Cervix
(“neck” of uterus)
Wall of uterus
Endometrium
(lining of uterus)
Vagina
Figure 27.2A
• Uterus
– __________
of fertilized egg
– Opens into
the ________
Ovaries
• Vagina
– Receives
penis during
intercourse
– Forms the
__________
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Oviduct
Corpus luteum Follicles
Uterus
Cervix
(“neck” of uterus)
Wall of uterus
Endometrium
(lining of uterus)
Vagina
Figure 27.2A
Oviduct
Ovary
Uterus
Bladder
(excretory system)
Rectum
(digestive system)
Pubic bone
Cervix
Urethra
(excretory system)
Shaft
Vagina
Glans
Bartholin’s gland
Clitoris
Prepuce
Labia minora
Labia majora
Vaginal opening
Figure 27.2C
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• Oogenesis
– Most of the process occurs within the ______
– Lifetime supply of _______ ______ is present
at birth
– One primary oocyte __________ each month
to form a secondary oocyte
– If the secondary oocyte is __________, it
completes meiosis and becomes a haploid
_______
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Diploid cell
In embryo
Differentiation and
onset of MEIOSIS I
PRIMARY OOCYTE,
arrested in prophase
of MEIOSIS I
Present at birth
Completion of MEIOSIS I
and onset of MEIOSIS II
SECONDARY OOCYTE,
arrested at metaphase
of MEIOSIS II;
released from ovary
First
polar body
Entry of sperm triggers
completion of MEIOSIS II
OVUM
(haploid)
Second
polar body
Figure 27.4B
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• Ovulation
– An egg cell is released from a __________ at
the surface of an ovary
– The orange mass below the ejected oocyte is part
of the ovary
Egg
cell
Figure 27.2B
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• Development of an ovarian follicle
Degenerating
corpus luteum
Start:
PRIMARY OOCYTE
within follicle
CORPUS LUTEUM
Growing
follicles
Mature follicle
SECONDARY
OOCYTE
Ovary
OVULATION
Ruptured follicle
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Figure 27.4C
Stimuli from other
areas in the brain
Hypothalamus
Anterior
pituitary
FSH
Negative feedback
Releasing
hormone
LH
Androgen
production
Testis
Sperm
production
Figure 27.3D
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Human Menstrual Cycle
• Happens in females, begins at __________
and ends at __________(45-50), regulates
the reproductive cycle, average cycle is
__________.
• Four “parts”/phases to a menstrual cycle.
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• Phase 1: happens from days 1-13
– __________ : anterior pituitary secretes
follicle stimulating hormone (FSH) and
luteinizing hormone (LH) which stimulates the
development of an ovum from a follicle and the
production of estrogen from the ovaries
respectively. Levels of LH spike on day 13
– __________ : the secretion of estrogen by the
ovaries causes the lining of the uterus
(__________) to accumulate fluid and cells to
support the developing embryo.
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• Phase 2: happens on day 14
– __________ : the spike in LH on day 13
causes the egg cell to be released from the
follicle, the egg cell is then transported down the
__________ toward the uterus by the
“current” formed from the cilia lining the
oviduct.
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• Phase 3: happens days 15-28
– __________ : the empty follicle shell fills with
fluid and materials and becomes a yellow body
called a __________ __________. The
corpus luteum secretes progesterone (more
estrogen also), which continues the _______ of
the endometrium. This also inhibits the
secretion of FSH and LH by the pituitary gland.
Around day 25 if the egg wasn’t fertilized the
corpus luteum starts to deteriorate, which
decreases the levels of __________ and
__________.
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• Phase 4: days 1-5 (overlap of next cycle)
– __________ : the endometrium breaks down
and the fluid and cells are __________ off of
the uterine lining. The anterior pituitary begins
secreting FSH and LH again (__________
above phases again).
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Hormones synchronize cyclical changes in the
ovary and uterus
Table 27.5
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(1)
Inhibited by combination
of estrogen and
progesterone
CONTROL BY HYPOTHALAMUS
Hypothalamus
Stimulated by high
levels of estrogen
Releasing
hormone
Anterior pituitary
FSH
(2)
LH
PITUITARY HORMONES
IN BLOOD
LH peak triggers
ovulation and
corpus luteum
formation
LH
FSH
FSH
LH
Figure 27.5
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(3) OVARIAN CYCLE
Growing
follicle
Mature
follicle
Ovulation
Corpus
luteum
Degenerating
corpus
luteum
Post-ovulatory phase
Pre-ovulatory phase
Progesterone
and estrogen
Estrogen
(4) OVARIAN HORMONES
IN BLOOD
Estrogen
Progesterone
Progesterone
and estrogen
Estrogen
(5) MENSTRUAL CYCLE
Endometrium
Menstruation
Days
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Figure 27.5 (continued)
PRINCIPLES OF EMBRYONIC DEVELOPMENT
Fertilization results in a zygote and triggers
embryonic development
• The shape of a human sperm cell is adapted to
its function
Plasma membrane
Middle
piece
Neck
Head
Tail
Mitochondrion
(spiral shape)
Nucleus
Acrosome
Enzyme tip, helps sperm
penetrate ovum
Figure 27.9B
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• Only ____ of these
sperm will penetrate
this human egg cell
to initiate
__________
– Fertilization is the
union of a sperm
and an egg to form a
diploid zygote
Figure 27.9A
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• Process of
fertilization
1 The sperm
approaches
the egg
2 The sperm’s
acrosomal enzymes
digest the
egg’s jelly
3 Proteins on the
coat
sperm head bind
to egg receptors
SPERM
4 The plasma membranes
of sperm and egg fuse
Sperm
head
5 The sperm
nucleus
enters
the egg
cytoplasm
Nucleus
Acrosome
Acrosomal
Plasma
membrane enzymes
6 A
fertilization
envelope
forms
Receptor protein
molecules
Plasma
membrane
Jelly
coat
Vitelline
layer
Cytoplasm
EGG CELL
Sperm
nucleus
Egg
nucleus
7 The nuclei
of sperm
and egg fuse
Zygote
nucleus
Figure 27.9C
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Cleavage produces a ball of cells from the zygote
• __________ is the first major phase of
embryonic development
– It is the rapid succession of cell __________
– It creates a __________ embryo from the
__________
– It partitions the multicellular embryo into
developmental __________
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• Cleavage in a
sea urchin
• Cleavage:
mitotic cell
divisions,
______ the
cell number
with each
division
without
______ the
overall size of
the object.
ZYGOTE
2 cells
4 cells
8 cells
Blastocoel
Many cells
(solid ball)
(Morula)
Figure 27.10
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BLASTULA
(hollow ball)
Cross section
of blastula
Gastrulation produces a three-layered embryo
• __________ is the second major phase of
embryonic development
– It adds more cells to the __________
– It sorts all cells into three distinct cell
__________
– The embryo is transformed from the
__________ into the __________
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• The three layers produced in gastrulation
– __________, the outer layer
– __________, an embryonic digestive tract
– __________, which partly fills the space
between the ectoderm and endoderm
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Animal pole
• Development of
frog gastrula
Blastocoel
1
Vegetal pole
BLASTULA
GASTRULATION
2
Blastopore
forming
Blastopore
forming
Blastocoel
shrinking
Archenteron
3
Archenteron
Ectoderm
Mesoderm
Endoderm
4
Yolk plug
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Yolk plug
GASTRULA
Figure 27.11C
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Organs start to form after gastrulation
• Embryonic tissue layers begin to differentiate
into specific tissues and organ systems
• In __________
– the notochord develops from the __________
– the neural tube develops from the __________
• The neural tube becomes the __________
and __________
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Table 27.12
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• The tissues and organs of a tadpole emerge
from cells of the ectoderm, mesoderm, and
endoderm
Figure 27.12D
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Changes in cell shape, cell migration, and
programmed cell death give form to the
developing animal
Ectoderm
• Tissues and organs
take shape in a
developing embryo
as a result of
– cell shape changes
– cell migration
Figure 27.13A
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– programmed
cell death
(________)
Cell
suicide
Dead cell
engulfed and
digested by
adjacent
cell
Figure 27.13B
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Embryonic induction initiates organ formation
• __________ is the mechanism by which one
group of cells influences the development of
tissues and organs from ectoderm, endoderm,
and mesoderm
– Adjacent cells and cell layers use chemical
signals to influence __________
– Chemical signals turn on a set of genes whose
expression makes the receiving cells differentiate
into a __________
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HUMAN DEVELOPMENT
The embryo and placenta take shape during the
first month of pregnancy
• Gestation is __________
– It begins at conception and continues until birth
– Human gestation is __________
(_________________)
– Mouse gestation is __________
– Elephant gestation is __________
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• Human development begins with fertilization
in the __________
Cleavage starts
Fertilization
of ovum
Ovary
Oviduct
Secondary
oocyte
Blastocyst
(implanted)
Ovulation
Endometrium
Uterus
Figure 27.16A
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• When the embryo implants into the uterus it
sends a chemical signal to the ovaries, this
signal is called ___ (_______ _______
_______ _______). This hormone signals
the ovaries to keep making progesterone and
stops the corpus luteum from breaking down.
Later when the placenta develops it secretes
hormones that inhibit the pituitary gland.
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• Cleavage produces
a blastocyst
ENDOMETRIUM
Inner cell mass
– A __________ is a
fluid-filled cavity
– The __________
of the blastocyst
form the baby
– The outer cells form
the embryo
__________
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Cavity
Trophoblast
Figure 27.16B
• The trophoblast secretes enzymes to enable the
blastocyst to __________ in the uterine wall
ENDOMETRIUM
Blood vessel
(maternal)
Future embryo
Multiplying cells
of trophoblast
Future
yolk sac
Trophoblast
UTERINE CAVITY
Figure 27.16C
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• Gastrulation occurs and organs develop from
the ectoderm, endoderm, and mesoderm
Amniotic
cavity
Amnion
Mesoderm
cells
Chorion
Yolk sac
Figure 27.16D
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• Meanwhile, the four embryonic membranes
develop
– ________
– ________
– ________
________
Chorion
Chorionic villi
Amnion
EMBRYO:
Allantois
Ectoderm
Mesoderm
Endoderm
Yolk sac
Figure 27.16E
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What do the embryonic membranes do in humans?
• 1. __________ will fill with fluid and
become a protective sac
• 2. __________ will become part of the
placenta
• 3. __________ will form part of the
umbilical cord and part of the urinary tract
• 4. __________ does not contain yolk and
will help form initial cells
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• The embryo floats in the fluid-filled amniotic
cavity, while the chorion and embryonic
mesoderm form the embryo’s part of the
placenta
Placenta
• The placenta’s
__________
absorb food
and oxygen
from the
mother’s
blood
Mother’s blood
vessels
Allantois
Yolk sac
Amniotic
cavity
Amnion
Embryo
Chorion
Chorionic
villi
Figure 27.16F
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• Although the reproduction method of desertgrassland whiptails is unusual, their embryonic
development is similar to all other animal
species
• Reptiles, birds,
and mammals
have four
embryonic
membranes
Chorion
Embryo
Amnion
Allantois
Yolk
Yolk sac
Shell
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Embryonic membranes
• __________
– Contains yolk (fat) for energy
• __________
– Outermost membrane, gas exchange
• __________
– Stores nitrogenous wastes from metabolism
• __________
– Surrounds developing embryo/fetus, contains amniotic fluid
(cushion and protect)
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• The __________ allows for a variety of
substances to pass from mother to fetus
– Protective antibodies
– German measles virus
– HIV
– Drugs (prescription and nonprescription)
– Alcohol
– Chemicals in tobacco smoke
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Human development from conception to birth is
divided into three trimesters
• First trimester
– First __________
– The __________ changes occur during the
first trimester
Figure 27.17A, B
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• Second trimester
– Increase in __________
– General __________ of human features
Figure 27.17C, D
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• Third trimester
– Growth and
__________
for birth
Figure 27.17E
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Childbirth is hormonally induced and occurs in
three stages
• Hormonal changes induce birth
– Labor is controlled by a __________ feedback
mechanism
– __________ released from the ovaries
increases the sensitivity of the uterus to
__________
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• __________ is a powerful stimulant for the
smooth muscles of the uterus
– Oxytocin also stimulates the placenta to make
__________ that stimulate the uterine
muscles to __________ even more
• Uterine contractions stimulate the release of
more and more oxytocin and prostoglandins
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from
ovaries
OXYTOCIN
From fetus
and pituitary
Induces oxytocin
receptors on uterus
Stimulates uterus
to contract
Positive feedback
ESTROGEN
Stimulates
placenta to make
PROSTAGLANDINS
Stimulates more
contractions
of uterus
Figure 27.18A
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• There are three
stages of labor
Placenta
• __________ of the
Umbilical
cord
cervix is the first
stage
Uterus
Cervix
– Cervix reaches full
______ at 10cm
– __________ of
labor (6-12 hours or
longer)
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1
Dilation of the cervix
Figure 27.18B, part 1
• _______ is the second stage
– Period from full
dilation of the cervix to
delivery of the infant
– Uterine contractions
occur every _______
– Mother feels urge to
push down with her
abdominal muscles
– Infant is forced down
and out of uterus and
vagina within a period
of __________
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2
Expulsion: delivery of the infant
Figure 27.18B, part 2
• The delivery of the
________ is the
final stage of labor
Uterus
– Usually occurs
within ________
after the birth of the
baby
Placenta
(detaching)
Umbilical
cord
3
Delivery of the placenta
Figure 27.18B, part 3
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• Hormones continue to be important after the
baby and placenta are delivered
– Decreasing progesterone and estrogen levels
allow the uterus to return to its __________
state
– Oxytocin and prolactin stimulate __________
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Connection: Reproductive technology increases our
reproductive options
• Reproductive technology
– Hormone therapy can increase sperm or egg
production
– Surgery can correct blocked oviducts
• Assisted reproductive
technology
– In vitro fertilization
(IVF)
• Surrogate motherhood
Figure 27.19
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Connection: Sexual activity can transmit disease
Table 27.7
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Connection: Contraception prevents unwanted
pregnancy
• Contraception prevents pregnancy in one of
three ways
– Blocking the
release of
gametes
– Preventing
fertilization
– Preventing
implantation
Figure 27.8
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Table 27.8
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