Transcript Chapter 16 The Female Reproductive System

Chapter 16
The Female
Reproductive System
The Reproductive System
 Gonads – primary sex organs
 Testes in males
 Ovaries in females
 Gonads produce gametes (sex cells) and
secrete hormones
 Male – sperm (gametes) and testosterone
(hormones)
 Female - Ova (eggs) and progesterone and
estrogen (hormones)
Female Reproductive System
 Function:
 Produce eggs
and sex
hormones
 Estrogen and
progesterone
 Prepare to
nurture a
developing
embryo for
nine months
Female Reproductive System
 Ovaries
 Duct System
 Uterine tubes
(fallopian
tubes)
 Uterus
 Vagina
 External
genitalia
Female Reproductive System
Figure 16.8a
Ovaries
 Paired ovaries
located in the
peritoneal cavity
 Composed
of ovarian follicles
(sac-like
structures)
 Structure of
an ovarian
follicle
 Oocyte - immature
egg
 Follicle cells
Figure 16.7
Ovarian Follicle Stages
 Primary follicle –
contains an
immature oocyte
 Graafian (vesicular)
follicle – growing
follicle with a
maturing oocyte
 Ovulation – when
the egg is mature
the follicle ruptures
 Occurs about
every 28 days
 The ruptured follicle
is transformed into
a corpus luteum
Support for Ovaries
 Suspensory ligaments – secure ovary to lateral walls
of the pelvis
 Ovarian ligaments – attach medially to uterus
 Broad ligament – a fold of the peritoneum, supports
the uterine tubes, uterus and vagina
Female Reproductive System
 Ovaries
 Duct System
 Uterine tubes
(fallopian
tubes)
 Uterus
 Vagina
 External
genitalia
Uterine (Fallopian) Tubes
 Receive the ovulated oocyte
 Provide a site for fertilization
 Attaches to the uterus
 Does not physically attach to the ovary
 Some eggs are lost
Uterine Tube Function
 Fimbriae – finger-like projections at the distal
end that receive the oocyte
 Cilia inside the uterine tube and peristalsis
slowly move the oocyte towards the uterus
(takes 3–4 days)
 Fertilization occurs inside the uterine tube
Uterine Tube Function
 Gonorrhea bacteria sometimes infects the
periotoneal cavity - between the ovary and
fallopian tube because it is not connected
 Causes severe inflammation called pelvic
inflammatory disease (PID)
 Major cause of female infertility
Uterus (womb)
 Never been pregnant – size and shape of a pear
 Located between the urinary bladder and rectum
 Hollow, thick-walled organ
 Functions of the uterus
 Receives, retains and nourishes a fertilized egg
Regions of the Uterus
 Body – main portion
 Fundus – area where uterine tube enters
 Cervix – narrow outlet that protrudes into the
vagina
Three Layers (walls) of the Uterus
 Endometrium
 Inner layer
 Allows for implantation of a fertilized egg
 Sloughs off if no pregnancy occurs (menses)
 Myometrium
 Middle layer of smooth muscle; contractions
and orgasms
 Serous layer
 Outer visceral peritoneum
Vagina
 Extends from cervix to exterior of body
 Behind bladder and in front of rectum
 Serves as the birth canal
 Receives the penis during sexual
intercourse
 Hymen – partially closes the vagina until it
is ruptured
External Genitalia (Vulva)
 Mons pubis
 Fatty area overlying
the pubic symphysis
 Covered with pubic
hair after puberty
 Labia – skin folds
 Labia majora
 Labia minora
Figure 16.9
External Genitalia
 Vestibule
 Enclosed by labia majora
 Contains opening of the
urethra and the greater
vestibular glands
(produce mucus)
 Clitoris
 Contains erectile tissue
 Corresponds to the male
penis
Oogenesis
 The total supply of eggs are present at
birth
 Ability to release eggs begins at puberty
 Reproductive ability ends at menopause
 Female gametes are produced by meiosis
 Oocytes are matured in developing
ovarian follicles
Oogenesis
 Oogonium – female stem cells found in
a developing fetus
 Oogonia undergo mitosis to produce
primary oocytes
 Primary oocytes are surrounded by cells
that form primary follicles in the ovary
Oogenesis
 Primary oocytes are inactive until puberty
 Follicle stimulating hormone (FSH) causes some
primary follicles to mature
 Ovarian cycle - primary follicles grow and mature
each month
 Meiosis starts inside maturing follicle
 Produces a secondary oocyte and the first polar
body
 Meiosis is completed after ovulation only if sperm
penetrates
Oogenesis
Figure 16.10
Menstrual (Uterine) Cycle
 Cyclic changes of the endometrium
 Regulated by cyclic production of
estrogens and progesterone
 Stages of the menstrual cycle
 Menses – functional layer of the
endometrium is sloughed
 Proliferative stage – regeneration of
functional layer
 Secretory stage – endometrium increases
in size and readies for implantation
Hormone Production by the Ovaries
 Estrogens
 Produced by follicle cells
 Endometrium is repaired and grows thick
 Forms glands in the endometrium
 Lack of estrogen and progesterone causes
endometrium to slough off (menses)
http://resources.schoolscience.co.uk/ABPI/new/reso
urces/hormones/en-flash/menstrualCycle.html
Hormone Production by the Ovaries
 Estrogens
 Cause secondary sex characteristics
 Enlargement of accessory organs
 Development of breasts
 Appearance of axillary and pubic hair
 Increase in fat beneath the skin
 Widening and lightening of the pelvis
 Onset of menses
Hormone Production by the Ovaries
 Progesterone
 Produced by the corpus luteum
 Helps maintain pregnancy
 Causes endometrial glands to begin
secretion of nutrients
 Maintains the myometrium in an inactive
state if implantation of an embryo has
occurred
Mammary Glands
 Present in both
sexes, but only
function in females
 Modified sweat
glands
 Function is to
produce milk
(lactation)
 Stimulated by sex
hormones (mostly
estrogens) to
increase in size
Stages of Pregnancy and
Development
 Fertilization
 Embryonic development
 Fetal development
 Childbirth
Fertilization
 The oocyte is
viable for 12 to 24
hours after
ovulation
 Sperm are viable
for 12 to 48 hours
after ejaculation
 Sperm cells must
make their way to
the uterine tube
for fertilization to
be possible
Mechanisms of Fertilization
 Membrane receptors on an oocyte pulls
in the head of the first sperm cell to
make contact
 The membrane of the oocyte does not
permit a second sperm head to enter
 The oocyte then undergoes its second
meiotic division
 Fertilization occurs when the genetic
material of a sperm combines with that
of an oocyte to form a zygote
The Zygote
 First cell of a new individual
 The result of the fusion of DNA from
sperm and egg
 The zygote begins rapid mitotic cell
divisions
 The zygote stage is in the uterine tube,
moving toward the uterus
The Embryo
 Developmental stage from the start of
cleavage until the ninth week
 The embryo floats free in the uterus
temporarily
 Uterine secretions are used for
nourishment
The Blastocyst
 Ball-like circle of cells
 Secretes human chorionic gonadotropin
(hCG) to produce the corpus luteum to
continue producing hormones
 The late blastocyst implants in the wall of
the uterus (by day 14)
Derivatives of Germ Layers
 Primary germ layers are eventually formed
 Ectoderm (outside layer)
 Nervous system
 Epidermis of the skin
 Mesoderm (middle layer)
 Everything else
 Endoderm (inside layer)
 Mucosae
 Glands
Development After Implantation
 The embryo is surrounded by the amnion (a fluid
filled sac)
 An umbilical cord forms to attach the embryo to
the placenta
Development from Ovulation to
Implantation
Functions of the Placenta
 Forms a barrier between mother and embryo
(blood is not exchanged)
 Delivers nutrients and oxygen
 Removes waste from embryonic blood
The Fetus (Beginning of the Ninth
Week)
 All organ systems are formed by the
end of the eighth week
 Activities of the fetus are growth and
organ specialization
 A stage of tremendous growth and
change in appearance
 By 270 days (nine months) the fetus is fullterm and ready to be born
In Vitro Fertilization
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http://video.nationalgeographic.com/video/
player/science/health-human-bodysci/human-body/ivf-sci.html
Sexually Transmitted Diseases
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Disease spread from one person to another during
sexual contact.
Infect millions in US each year
There are more than 25 different diseases
Viral
 Human papilloma virus (HPV)
 Herpes (genital)
 Hepatitis A, B, and C (generally B)
 Human immunodeficiency virus (HIV)
Bacterial
 Syphilis
 Gonorrhea
 Chlamydia
Sexually Transmitted Diseases
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Viral
 Herpes (genital)
~45 million people are infected with it
 Two types of herpes (HSV -1 causes oral herpes and
HSV -2 causes genital herpes)
 Symptoms include pain and itching in infected areas
 Lesions in the genital areas and buttocks
 No cure for the virus
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Sexually Transmitted Diseases
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Viral
 Humanpapilloma virus (HPV)
About 80% of humans are infected
 100 different types of HPV and ~ 30 are STD
 Usually no symptoms but some can lead to genital warts
 No cure for the virus
 Some types can lead to cervical cancer
 Females – have a vaccine to prevent HPV
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Sexually Transmitted Diseases
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Viral
 Hepatitis A, B, and C (generally B)
Hepatitis B attacks your liver and usually leads to death
 ~1.25 million Americans infected with
 Vaccine available to prevent infection
 Usually no symptoms but some experience jaundice, and
flu symptoms
 No cure for the virus
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Sexually Transmitted Diseases
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Viral
 Human immunodeficiency virus (HIV)
Virus attacks your immune system (t-helper cells that fight
off infections
 Eventually the body cannot fight off infections
 When this happens the person acquires AIDS
 First few weeks feel like you have the flu but then no
symptoms
 No cure for the virus but medications to help
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Sexually Transmitted Diseases
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Bacterial
 Syphilis
Majority of sufferers are males
 Syphilis can be treated if caught early
 If untreated it can lead to heart problems, blindness and
death
 Primary syphilis results in painless sores, secondary
syphilis results in a rash with a fever and fatigue, third
stage can last for years and end in blindness, numbness,
and death
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Sexually Transmitted Diseases
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Bacterial
 Gonorrhea (the clap)
Most people infected are under the age of 30
 Can be cured by antibiotics
 Difficult to diagnose because it usually presents with
urinary symptoms
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Sexually Transmitted Diseases
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Bacterial
 Chlamydia (‘silent disease’)
Most common STD
 ~ 3 million cases per year
 Usually no symptoms but some people experience
discharge and painful urination
 Antibiotics can cure the infection
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