Human
Reproduction
& Development
Meiosis
 An Overview of Meiosis
 In human beings, nearly all cells have paired sets of chromosomes, meaning these
cells are diploid. Meiosis is the process by which a single diploid cell divides to
produce four haploid cells—that contain a single set of chromosomes.
 The haploid cells produced through meiosis are called gametes. Female gametes
are eggs; male gametes are sperm. They are the reproductive cells of human
beings and many other organisms.
 When the haploid sperm and haploid egg fuse, a diploid fertilized egg (or zygote) is
produced, setting into development a new generation of organism.
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Meiosis
 There are two stages of meiosis, namely, meiosis I and meiosis II. The parent cell or
the dividing cell undergoes a preparatory phase, known as interphase, before entering
the two stages of meiosis.
 In the interphase, the parent cell synthesizes more DNA and proteins, increasing the
overall size and mass of the cell. As a part of the preparatory phase, the dividing cell
duplicates or doubles its chromosomes. With these major changes, the parent cell
enters the first stage of meiosis.
The following is a brief description about the two stages and their phases:
Meiosis I:
 Prophase I: Duplicated chromatin condenses. Each chromosome consists of two,
closely associated sister chromatids. Crossing-over can occur during the latter part
of this stage.
 Metaphase I: Homologous chromosomes align at the equatorial plate.
 Anaphase I: Homologous pairs separate with sister chromatids remaining together.
 Telophase I: Two daughter cells are formed with each daughter containing only one
chromosome of the homologous pair.
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Meiosis
Meiosis II:
 Prophase II: DNA does not replicate.
 Metaphase II: Chromosomes align at the equatorial plate.
 Anaphase II: Centromeres divide and sister chromatids migrate separately to each
pole.
 Telophase II: Cell division is complete. Four haploid daughter cells or gametes are
formed.
 The resulting four gametes are haploid; meaning they contain half the number of
chromosomes. This is the reason as to why meiosis cell division is also referred to as
reduction division. During fertilization, two gametes, one from the mother and another
from the father, fuse, thus resulting in doubling of chromosome number. The fusion
of gametes leads to the production of a zygote thus has the same chromosome number
of the parents. Variation occurs in the resulting zygote due to the process of meiosis
and fertilization of gametes. Zygote after attaining maturity, is capable of dividing into
daughter cells.
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Figure 1: Meiosis
Overview:
 1st Division is very important as it
reduces the numbers of chromosomes
by half.
 Prophase I has the homologous
chromosomes (chromosomes that
appear identical to one another because
they carry the same genes, one comes
from our mom, and the other comes
from our dad) crossing over to
exchange material.
 Metaphase I have the homologous
pairs line up at the equator of the cell
and in Anaphase I, the homologous
chromosomes separate and thus
reducing the chromosome number in
each cell.
 2nd Division of Meiosis is exactly like
mitosis, except that 2 cells start off in
prophase 2 and you end up with 4
daughter cells that are completely
different from each other.
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Gametogenesis
 Gametogenesis is the development and
production of the male and female germ
cells required to form a new individual.
 The male and female germ cells are called
gametes.
 In males, the gametes (sperm) are
produced by the testes.
 In females, the gametes (eggs or ova) are
produced by the ovaries.
 During sexual intercourse, an ejaculated
sperm cell penetrates an egg and unites with
it (fertilizes it). The fertilized egg is called the
zygote.
 Figure 2 : Gametogenesis
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Oogenesis
 Oogenesis is the formation of the ovum (female sex cells), which begin as hundreds of
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thousands of oogonia (stem cells) in the fetal ovaries.
In the ovaries of human females, primary oocytes with 46 chromosomes divide
meiotically to form two cells, each with 23 duplicated chromosomes.
One of the cells, a secondary oocyte, receives most cytoplasm; the other cell, a polar
body, disintegrates or divides again.
A secondary oocyte begins meiosis II and then stops at metaphase II.
At ovulation, the secondary oocyte leaves the ovary and enters an oviduct where it may
meet a sperm.
If a sperm enters secondary oocyte, the oocyte is activated to continue meiosis II to
completion; the result is a mature egg and another polar body, each with 23 daughter
chromosomes.
Meiosis produces one egg and three polar bodies; polar bodies serve to discard
unnecessary chromosomes and retain most of the cytoplasm in the egg.
The cytoplasm serves as a source of nutrients for the developing embryo.
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Figure 3: Oogenesis
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Spermatogenesis
 Spermatogenesis is the production of mature sperm cells.
 In the testes of males, primary spermatocytes with 46 chromosomes divide
meiotically to form two secondary spermatocytes, each with 23 duplicated
chromosomes.
 Secondary spermatocytes divide to produce four spermatids, also with 23 daughter
chromosomes.
 Spermatids then differentiate into sperm.
 Meiotic cell division in males always results in four cells that become sperm.
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Figure 4: Spermatogenesis
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Female Reproductive Anatomy
 The female reproductive system is designed to carry out several functions as follows:
 It produces the female egg cells necessary for reproduction, called the ova or
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oocytes.
The system is designed to transport the ova to the site of fertilization.
Conception, the fertilization of an egg by a sperm, normally occurs in the fallopian
tubes.
After conception, the uterus offers a safe and favorable environment for a baby to
develop before it is time for it to make its way into the outside world.
If fertilization does not take place, the system is designed to menstruate (the
monthly shedding of the uterine lining).
In addition, the female reproductive system produces female sex hormones that
maintain the reproductive cycle.
 During menopause the female reproductive system gradually stops making the female
hormones necessary for the reproductive cycle to work. When the body no longer
produces these hormones a woman is considered to be menopausal.
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Internal Female Reproductive
Anatomy
 The female reproductive anatomy includes internal and external structures.
 The internal reproductive organs include:
 Vagina: The vagina is a canal that joins the cervix (the lower part of uterus) to the
outside of the body. It also is known as the birth canal.
 Uterus (womb): The uterus is a hollow, pear-shaped organ that is the home to a
developing fetus. The uterus is divided into two parts: the cervix, which is the lower
part that opens into the vagina, and the main body of the uterus, called the corpus.
The corpus can easily expand to hold a developing baby. A channel through the
cervix allows sperm to enter and menstrual blood to exit.
 Ovaries: The ovaries are small, oval-shaped glands that are located on either side
of the uterus. The ovaries produce eggs and hormones.
 Oviducts : Also known as fallopian tubes, are narrow tubes that are attached to the
upper part of the uterus and serve as tunnels for the ova (egg cells) to travel from
the ovaries to the uterus. Conception, the fertilization of an egg by a sperm,
normally occurs in the fallopian tubes. The fertilized egg then moves to the uterus,
where it implants to the uterine wall.
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External Female Reproductive
Anatomy
 The function of the external female reproductive structures (the genital) is twofold: To
enable sperm to enter the body and to protect the internal genital organs from
infectious organisms. The main external structures of the female reproductive system
include:
 Labia majora: The labia majora enclose and protect the other external
reproductive organs. Literally translated as "large lips," the labia majora are
relatively large and fleshy, and are comparable to the scrotum in males. The labia
majora contain sweat and oil-secreting glands. After puberty, the labia majora are
covered with hair.
 Labia minora: Literally translated as "small lips," the labia minora can be very
small or up to 2 inches wide. They lie just inside the labia majora, and surround the
openings to the vagina (the canal that joins the lower part of the uterus to the
outside of the body) and urethra (the tube that carries urine from the bladder to
the outside of the body).
 Bartholin’s glands: These glands are located next to the vaginal opening and
produce a fluid (mucus) secretion.
 Clitoris: The two labia minora meet at the clitoris, a small, sensitive protrusion that
is comparable to the penis in males. The clitoris is covered by a fold of skin, called
the prepuce, which is similar to the foreskin at the end of the penis. Like the penis,
the clitoris is very sensitive to stimulation and can become erect.
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Female Reproductive Anatomy
(Continued)
 Mammary Glands
 They are not part of the female reproductive tract but are important secondary
reproductive organs.
 The mammary glands develop in the tissue underneath the skin but on top of the
muscles of the chest.
 Both males and females start with the same tissues, but normally only females
generate the correct hormonal signals to promote development of the mammary
glands at puberty.
 The full ability of mammary glands to synthesize and secrete milk does not occur
unless a woman is exposed to the hormonal changes of pregnancy.
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Figure 5: Female Reproductive
Anatomy
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Male Reproductive Anatomy
 The purpose of the organs of the male reproductive system is to perform the following
functions:
 to produce, maintain, and transport sperm (the male reproductive cells) and
protective fluid (semen);
 to discharge sperm within the female reproductive tract during sex; and
 to produce and secrete male sex hormones responsible for maintaining the male
reproductive system.
 The entire male reproductive system is dependent on hormones, which are chemicals
that regulate the activity of many different types of cells or organs. The primary
hormones involved in the male reproductive system are follicle-stimulating hormone,
luteinizing hormone, and testosterone.
 Follicle-stimulating hormone is necessary for sperm production (spermatogenesis) and
luteinizing hormone stimulates the production of testosterone, which is also needed to
make sperm. Testosterone is responsible for the development of male characteristics,
including muscle mass and strength, fat distribution, bone mass, facial hair growth,
voice change, and sex drive.
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External Male Reproductive
Anatomy(Continued)
 Most of the male reproductive system is located outside of the body. These external
structures include the following:
 Penis: This male organ is used in sexual intercourse. It has three parts: the root,
which attaches to the wall of the abdomen; the body, or shaft; and the glans,
which is the cone-shaped part at the end of the penis. The glans, also called the
head of the penis, is covered with a loose layer of skin called foreskin. This skin is
sometimes removed in a procedure called circumcision. The opening of the
urethra, the tube that transports semen and urine, is at the tip of the penis. The
penis also contains a number of sensitive nerve endings.
 Scrotum: The scrotum is a thin sac of skin and thin muscle in which lie the
testicles. The scrotum acts as a climate control system, allowing the testicles to be
slightly away from the rest of the body and keeping them slightly cooler than
normal body temperature for optimal sperm development.
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External Male Reproductive
Anatomy (Continued)
 Testicles (testes): The testes (or testicles) are two olive-sized oval bodies, one on
the right side and one on the left side. The testes have two main functions: to
produce sperm (the male sex cell) and to produce testosterone (the male sex
hormone).
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Internal Male Reproductive
Anatomy
 The internal organs of the male reproductive system, also called accessory organs,
include the following:
 Epididymis: The epididymis is a long, coiled tube that rests on the backside of each
testicle. It functions in the transport and storage of the sperm cells that are
produced in the testes. It also is the job of the epididymis to bring the sperm to
maturity, since the sperm that emerge from the testes are immature and incapable
of fertilization. During sexual arousal, contractions force the sperm into the vas
deferens.
 Vas deferens: The vas deferens is a long, muscular tube that travels from the
epididymis into the pelvic cavity, to just behind the bladder. The vas deferens
transports mature sperm to the urethra in preparation for ejaculation.
 Ejaculatory ducts: These are formed by the fusion of the vas deferens and the
seminal vesicles. The ejaculatory ducts empty into the urethra.
 Urethra: The urethra is the tube that carries urine from the bladder to outside of
the body. It has the additional function of expelling (ejaculating) semen when the
man reaches orgasm. When the penis is erect during sex, the flow of urine is
blocked from the urethra, allowing only semen to be ejaculated at orgasm.
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Internal Male Reproductive
Anatomy (Continued)
 Seminal vesicles: The seminal vesicles are sac-like pouches that attach to the vas
deferens near the base of the bladder. The seminal vesicles produce semen, a fluid
that activates and protects the sperm after it has left the penis during ejaculation.
 Prostate gland: The prostate gland is a walnut-sized structure that is located below
the urinary bladder in front of the rectum. The prostate gland contributes
additional fluid to the ejaculate. Prostate fluids also help to nourish the sperm. The
urethra, which carries the ejaculate to be expelled during orgasm, runs through the
center of the prostate gland.
 Bulbourethral glands: The bulbourethral glands, or Cowper’s glands, are pea-sized
structures located on the sides of the urethra just below the prostate gland. These
glands produce a clear, slippery fluid that empties directly into the urethra. This
fluid serves to lubricate the urethra and to neutralize any acidity that may be
present due to residual drops of urine in the urethra.
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Figure 6: Male Reproductive
Anatomy
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Human Sexual
Cycles & Response
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Kinds of Physiological Reactions
Myotonia
Vascongestion
 Defined as increased muscle
tension
 During this kind of response,
muscles can contract rather
quickly or can slow down
 Is what usually happens with an
orgasm
•Happens when tissue in the body
is filled with blood
•Blood flows very fast through the
arteries of that tissue
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Figure 7: Sexual Response Cycle
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Phases of the Sexual
Response Cycle
 1) Excitement
 The first part is really mental. Once this occurs, the brain send signals that make
blood pressure and the heart rate go up, which increases blood flow to the genitals,
called engorgement. Vaginal lubrication happens. Here, the inner part of the vagina
expands, the labia lips open and get bigger, then the clitoris swells and pulls back
against the pubic bone. For males, the penis becomes erected. Here, it is enlarged
and stiffened with blood rushing within it (vasocongestion).Tight muscles at the
base of the penis hold the blood in.
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Phases of the Sexual
Response Cycle (Continued)
 2) Plateau
 Muscle tensions and the heart rate increase. The outer part of the vagina swells up
and gets tighter and the inner part expands. When this occurs, the uterus is in a
certain position where it can get the sperm that has passed through the vagina,
assuming there is sperm. It tends to form a dent-like shape, that sperm can easily
fall into.
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Phases of the Sexual
Response Cycle (Continued)
 3) Orgasm
 The ultimate goal of sexual intercourse, also called coitus, is the orgasm. Muscle
tensions reach their highest point and are released, usually in a series of involuntary
muscle contractions from the genitals. For males, first the glands and ducts contract
(emission), forcing semen to go into the urethra, where sperm comes out through
ejaculation
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Phases of the Sexual
Response Cycle (Continued)
 4) Resolution
 The end of the cycle where everything slows down and goes back to normal within
5 minutes. Muscles relax, making the genitals return to their usual shape, size, and
color. Major sex organs such as the penis and clitoris can take longer than 5
minutes to return to their normal being.
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Hormonal Control of the
Male Reproductive System
 Testosterone and other androgens
 Are directly responsible for the primary and secondary sex characteristics of the
male
 Androgen secretion and sperm production
 Are both controlled by hypothalamic and pituitary hormones
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Figure 8 & 9: Hormonal Control of
the Male Reproductive System
Stimuli from other
areas in the brain
Hypothalamus
GnRH from the
hypothalamus regulates FSH and LH
release from the
anterior pituitary.
FSH acts on the
Sertoli cells of the
seminiferous
tubules, promoting
spermatogenesis.
Figure 46.14
Anterior
pituitary
Negative
feedback
LH stimulates the
Leydig cells to make
testosterone, which
in turn stimulates
sperm production.
Leydig cells
make
testosterone
Sertoli cells
Spermatogenesis
Primary and
secondary sex
characteristics
Testis
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Important Male Sex Hormones
Key hormones are androgens, such as testosterone. Testosterone is a steroid that is
made in the testes by Leydig cells.
 It makes up many male characteristics such as the making of sperm and the genitals,
hair growth and deeper voices
 It controls sexual behavior/sex drive
 In addition to testosterone, hormones and glands such as the anterior pituitary and
hypothalamus control the amount of androgen being released and sperm production in
the testes
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Figure 10: Testosterone
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Reproductive Cycles of the Female
 The Ovarian Cycle
1.
The hormone GnRH (gonadotropin releasing hormone) is released, which gets the
pituitary gland to release FSH (follicle-stimulating hormone) and LH (luteinizing
hormone)
2.
FSH works with LH to stimulate follicle growth to make estrogen. As estrogen is
secreted, it goes through the follicular phase. Out of the many follicles being made,
one follicle survives and grows. FSH and LH levels are low due to low estrogen
levels
3.
Estrogen levels increase as the follicle rises, also increasing LH and FSH levels and
GnRH levels that were secreted, stimulated by the hypothalamus.
4.
The follicle responds more to LH because it has receptors for it. Increasing LH
levels are caused by increasing estrogen secretions from the follicle (positive
feedback)
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The Ovarian Cycle (Continued)
5.
The follicle continues to grow, forming barriers around itself. It then moves towards
an ovary and eventually attaches itself to it, causing ovary rupture and releases a
secondary oocyte (a haploid cell resulting from meiosis). From the time this cell
moves from the ovary to its discharge unless fertilized is ovulation
6.
After ovulation, the luteal phase occurs. Here, LH stimulates the changing of the rest
of the follicular tissue that was left behind after the secondary oocyte was released. It
forms the corpus luteum. Once this is stimulated, it secretes estrogen and
progesterone, leading to the secretion of LH ad FSH. If the corpus luteum
disintegrates, levels of estrogen and progesterone decrease. This alerts the pituitary
gland of what just happened, allowing it to make new follicles for the next time, and
the cycle starts all over again.
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Important Hormones Related To
the Female Reproductive System
•Cyclic secretion of GnRH from the hypothalamus
And of FSH and LH from the anterior pituitary orchestrates the
female reproductive cycle
•Five kinds of hormones
Participate in an elaborate scheme involving both positive and
negative feedback
Figure 11: Estriol (a form of estrogen)
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Figure 11: The Ovarian Cycle
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The Uterine/Menstrual Cycle
1.
After ovulation, estrogen and progesterone given off by the corpus luteum still
continue to stimulate the endometrium, which is the inner lining of the uterus that
has many blood vessels. Glands within it release nutrients that are for an embryo,
even if there is no embryo to nurture. As time goes on, the secretory phase is
initiated. Here, blood lining becomes thicker.
2.
The corpus luteum disintegrates and arteries in the uterine lining are not getting
enough blood. When this happens, about 2/3 of the endometrium disintegrates as
well, resulting in menstruation. Menstruation can last an average of 5 days and
occurs an average of every 28 days, where the cycle starts all over again.
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Figure 12: The Uterine/Menstrual
Cycle
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Menopause
 Human females can have an average of 450 menstruation cycles in their lifetime
 Menopause is the stage of a female’s life where she stops producing hormones such as
LH and FSH in the ovaries. This means that without the proper hormones, a female
can no longer have children. This happens to women between the ages of 46 and 54,
and sometimes earlier or later
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Conception,
Embryonic
Development, &
Birth
40
Pregnancy
 Humans are placental (eutherian) mammals.
 Gestation or pregnancy takes place in humans
 It is the condition of carrying one or more embryos in the uterus.
 Human pregnancy averages from 266 days (38 weeks) from fertilization of the egg,
or 40 weeks from the start of the last menstrual cycle.
 A pregnancy includes a first, second, and third trimester.
 Human gestation can be divided for convenience into three trimester of about three
months each.
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Fertilization
• Once the sperm meets the egg, fertilization occurs and the egg begins to divide.
• Immediately after fertilization, the gender is determined.
• The fertilized egg begins to divide repeatedly and the zygote grows in size.
• The inner cells will become the embryo while the outer group of cells will become the
placenta
• The mother is beginning to produce progesterone and estrogen, the pregnancy
hormones that will be responsible for a host of bodily changes (and symptoms like
morning sickness) to come.
 It makes its way down the fallopian tube to the uterus where it will implant itself to
the uterine wall.
 This generally takes a week before the zygote enters the uterus and 72 hours
before it is implanted in the uterine wall when it does reach the uterus.
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Figure 13: Formation of the zygote
and early postfertilization events
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First Trimester
 Is the main period of organogenesis
 Development of body organs
 During the first trimester:
 Fertilized egg implants in uterine lining
 Placenta and umbilical cord develop
 Spinal cord and embryo’s three layers that will eventually become organs form
 Heart begins to beat and blood is pumped
 At the end of the third month, fetus is completely formed
 At week 11 Baby is now officially described as a fetus.
 The fifth week of pregnancy, or the third week after conception, marks the beginning
of the embryonic period. This is when the baby's brain, spinal cord, heart and other
organs begin to form.
Second Trimester
 During this trimester, the fetus grows to about 30 cm and is very active.
 The mother may feel movements during the early part of the second trimester.
 The uterus grows enough for pregnancy to be obvious.
 Fetal activity may be visible through the abdominal wall by the middle of this
time period.
 There are some changes with hormones during this time
 Hormone levels stabilize as HCG declines.
 The corpus luteum deteriorates.
 The placenta completely takes over the production of progesterone which
maintains the pregnancy
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Third Trimester
 During this trimester the growth of the fetus is about 3-4 kg and 50 cm.
 Fetal activity may decrease because there is less room for movement.
 As the fetus grows and the uterus expands around it the mother’s abdominnal
organs become compressed and displaced, leading to frequent urination, digestive
blockages, and strain in the back muscles.
 A complex interplay of local regulators (prostaglandins) and hormones (mostly
estrogen and oxytocin) induces and regulates labor.
 Labor- the process by which childbirth occurs.
 Estrogen- is thought to induce oxutocin receptors on the uterus, it reaches its
highest level in the mother’s blood during the last weeks of pregnancy.
 Oxytocin- it is produced by the fetus and the mother’s posterior pituitary.
 It stimulates the placenta to secrete prostaglandins, which enhance powerful
contractions.
 Physical and emotional stresses associated with the contractions stimulate the
release of more oxytocin and prostaglandins, a positive feedback system, that
underlies the process of labor.
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Figure 14: Induction of Labor
from
ovaries
Oxytocin
from fetus
and mother's
posterior pituitary
Induces oxytocin
receptors on uterus
Stimulates uterus
to contract
Positive feedback
Estrogen
Stimulates
placenta to make
Prostaglandins
Figure 46.18
Stimulate more
contractions
of uterus
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Parturition & Lactation
 Parturition- or birth is brought about by a series of strong, rhythmic uterine
contractions.
 The process of labor has three stages:
 1. The opening up and thinning of the cervix, ending with complete dilation.
 2. The expulsion, or delivery of the baby.
Continuous strong contractions force the fetus down and out of the uterus and
vagina.
 3. The delivery of the placenta, which normally follows the baby.
 Lactation- release of milk from the mammary glands that is controlled by oxytocin,
 This is unique to mammals.
 After birth decreasing levels of progesterone free the anterior pituitary from
negative feedback and allow prolactin secretion.
 Prolactin stimulates milk production after a delay of 2 or 3 days.

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Figure 15: The Three Stages of
Labor
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
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Contraception
& Abortion
50
Contraception: A Summary
 Is the deliberate prevention of pregnancy
 Can be achieved in different ways
 Some prevent the release of mature eggs
 Others keep the sperm and the egg apart
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Weakest Forms of Contraception
 Withdrawal (Pull-Out Method) Withdrawal is also called coitus interruptus or the "pull
out method"
 A man who uses withdrawal will pull his penis out of the vagina before ejaculation
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— the moment when semen spurts out of his penis.
Withdrawal prevents pregnancy by keeping sperm out of the vagina. Pregnancy
cannot happen if there is no sperm present.
Requires great self-control, experience, and trust
Is not for men who ejaculate prematurely
Is not for men who don't know when to pull out
Is not recommended for teens and sexually inexperienced men because it takes lots
of experience before a man can be sure to know when he's going to ejaculate
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Weakest Forms of Contraception
 Spermicide
 Spermicides prevent pregnancy by keeping sperm from joining with an egg.
 Spermicides are inserted deep into the vagina shortly before intercourse. They
 block the cervix, so sperm cannot reach an egg
 keep sperm from moving, so they cannot join with an egg
 If not used exactly as directed, spermicides may not form a good barrier over the
cervix. This may make the spermicide less effective.
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Condoms
 Male Condom
 Condoms are thin latex or plastic
sheaths that are worn on the penis
during intercourse.
 They prevent pregnancy and reduce
the risk of sexually transmitted
diseases (STDs).
 Like all birth control methods,
condoms are more effective when
you use them correctly.
 Female Condom
 The female condom is a plastic pouch
that is used during intercourse to
prevent pregnancy and reduce the risk
of sexually transmitted diseases.
 It has flexible rings at each end.
 Just before vaginal intercourse, it is
inserted deep into the vagina.
 The ring at the closed end holds the
pouch in the vagina.
 The ring at the open end stays outside
the vaginal opening during intercourse.
 Female condoms work to prevent
pregnancy by covering the inside of the
vagina. They collect pre-cum and semen
when a man ejaculates. This keeps
sperm from entering the vagina.
Rhythm Method
 Depends on abstaining or using condoms during intercourse when conception is most
likely.
 Must keep track of ovulation with the help of:
 Changes in the cervical mucus and body temperature during the menstrual cycle
Diaphragm and Sponge
 Diaphragm
 Is a shallow, dome-shaped cup with
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


a flexible rim.
It is made of latex.
Covers the cervix
The diaphragm must be used with
spermicide cream or jelly.
Together the diaphragm blocks the
opening to the uterus and the
spermicide stops sperm from
moving.
 Sponge
 The sponge is made of plastic foam
and contains spermicide.
 It is soft, round, and about two
inches in diameter.
 It has a nylon loop attached to the
bottom for removal.
 It is inserted deep into the vagina
before intercourse.
 The sponge covers the cervix and
blocks sperm from entering the
uterus.
 The sponge also continuously
releases a spermicide that keeps
sperm from moving.
Birth Control Patch and The Pill
 Birth Control Patch (Ortho Evra)
 The birth control patch is a thin, beige,
plastic patch that sticks to the skin.
 The hormones in the patch are the same
hormones as in the birth control pill —
estrogen and progestin.
 The hormones work by keeping a
woman’s ovaries from releasing eggs —
ovulation.
 Also thickens cervical mucus and causes
the lining of the uterus to become
thinner
 The birth control patch is very effective.
It works best when it is always placed
on the skin on time. That keeps the
correct level of hormone in a woman’s
body.
 The Pill
 Birth control pills are a kind of
medication that women can take daily to
prevent pregnancy
 The hormones in the pill work by
keeping a woman’s ovaries from
releasing eggs — ovulation.
 The hormones in the pill also prevent
pregnancy by thickening a woman’s
cervical mucus. The mucus blocks
sperm and keeps it from joining with an
egg.
The hormones also thin the lining of
the uterus. In theory, this could prevent
pregnancy by keeping a fertilized egg
from attaching to the uterus.
 Birth control pills are very effective.
Vasectomy and Tubal Sterilization
Vasectomy
Tubal Sterilization
 A vasectomy closes or blocks the tubes
that carry sperm.
 Closes or blocks a woman's fallopian
tubes.
 When the tubes are closed, sperm
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cannot leave a man's body and
cause pregnancy.
Vasectomy blocks each vas deferens and
keeps sperm out of the seminal fluid.
The sperm are absorbed by the body
instead of being ejaculated.
Nearly 100 percent effective.
But usually takes 3 months to be
effective
It is meant to be permanent
 Can be done in several ways:
 One way is by tying and cutting the
tubes — this is called tubal ligation.
 Can be sealed using an instrument
with an electrical current
 Closed with clips, clamps, or rings
 A small piece of the tube can be
removed
 Nearly 100 percent effective
 Also permanent
Abortion
 Is the termination of pregnancy.
 This includes miscarriages
 Done before the fetus is viable
 Two legal ways:
 The abortion pill
 In-clinic abortion
Legal Abortion Methods
Abortion Pill (RU-486 or
mifepristone)
In-Clinic Procedures
 The abortion pill is a medicine that ends
an early pregnancy
 Done after the ninth week of pregnancy
 Can be used up until the ninth week of
 Most common is aspiration
pregnancy
 The abortion pill works by blocking the
hormone progesterone. Without
progesterone, the lining of the uterus
breaks down, and pregnancy cannot
continue.
 Another pill must be taken which causes
the uterus to empty
 Uses a vacuum to empty the uterus
 Used up to 16 weeks
 Another is D&E (Dilation and
Evacuation)
 Empties the uterus after expanding
the cervix
 Used after 16 weeks
Figure 16: Mechanisms of some
contraceptive methods
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Modern Reproductive Technology
 Recent scientific and technological advances
 Have made it possible to deal with many reproductive problems
 Amniocentesis and chorionic villus sampling
 Are invasive techniques in which amniotic fluid or fetal cells are obtained for
genetic analysis
 Noninvasive procedures
 Usually use ultrasound imaging to detect fetal condition
 Modern technology
 Can help infertile couples by in vitro fertilization
 During in vitro fertilization oocytes are mixed with sperm in culture dishes and
allowed time to fertilize. Then the cells that form are inserted into the woman’s
uterus and allowed to implant.
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Word Find: Fetal Development
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Words to find
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Ectoderm
fertilization
uterine wall
embryo quickening
progesterone
estrogen
zygote
pancreas
sucking motions
fat stores
vernix caseosa
lanugo
red blood cells
primitive circulatory
amniotic fluid
development of external genitalia
blastocyst
embryonic period
fetus
mesoderm
endoderm
umbilical cord
neural tube
Solution
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Fill In’s
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Fill In’s Continued
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Fill In’s Continued
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Fill In’s Continued
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Cross Word Puzzle
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Clues
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Solution
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Study Sites
The following are helpful study sites organized by topic:
 Cell Division: Meiosis and Sexual Reproduction:
 http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmeiosis.html
 Sexual Reproduction:
 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Sexual_Reproduction.html
 http://www.cliffsnotes.com/study_guide/The-Male-Reproductive-System.topicArticleId-22032,articleId22026.html
 The Reproductive System:
 http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookREPROD.html
 http://library.thinkquest.org/2935/Natures_Best/Nat_Best_Low_Level/Reproductive_page.L.html
 All Systems: Male/Female Reproductive anatomy:
 http://www.innerbody.com/htm/body.html
 http://www.brown.edu/Courses/BI0032/abortion/femrepcycle.html
 http://www.billings-ovulation-method.org.au/act/physiolo.shtml
 Gametogenesis
 http://staff.um.edu.mt/acus1/GAMETOGENESIS.htm
 http://science.jrank.org/pages/2915/Gametogenesis.html
 http://www.biology-questions-and-answers.com/gametogenesis.html
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Study Sites Continued
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Oogenesis
http://www.brown.edu/Courses/BI0032/gentherp/oogIC.html
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=dbio&part=A4695
http://main.uab.edu/show.asp?durki=19786
Spermatogenesis
http://www.rci.rutgers.edu/~uzwiak/HumanSexuality/HSSpringLect3.htl (pictures don’t seem to work but the
info is good)
http://main.uab.edu/show.asp?durki=19482
Embryonic Development
http://www.answersingenesis.org/home/area/cfol/ch1-development.asp
http://virtualhumanembryo.lsuhsc.edu/HEIRLOOM/Stages/HEP.htm
http://embryology.med.unsw.edu.au/wwwhuman/Stages/CStages.htm
Sexual Hormones
http://www.gfmer.ch/Endo/Lectures_08/sexual_hormones.htm
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexHormones.html
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