Transcript Reproductive System

REPRODUCTIVE
SYSTEM
REPRODUCTIVE SYSTEM
 The
Reproductive System, unlike other
systems we have studied, IS NOT
ESSENTIAL to the survival of an
INDIVIDUAL.
 What the Reproductive System is
important to is the Survival of the
SPECIES. Reproduction is absolutely
essential to the continuation of the
SPECIES…SOME OF US MUST
REPRODUCE!
SEXUAL DEVELOPMENT
For the First SIX Weeks after fertilization,
human male and female Embryos are Identical in
appearance.
 During the SEVENTH Week of development,
major changes occur:

7TH WEEK CHANGES:
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A. The TESTES, which are the PRIMARY Reproductive
Organs of a MALE, begin to produce Steroid Hormones
(Sex) known as ANDROGENS. The tissue of the Embryo
responds to these hormones by developing into the MALE
REPRODUCTIVE ORGANS.
B. The OVARIES, or the PRIMARY Reproductive
Organs of a FEMALE Embryo, produce Steroid Hormones
(Sex) known as ESTROGENS. The tissue of the Embryo
responds to these hormones by developing into the
FEMALE REPRODUCTIVE ORGANS.
. Neither Testes or Ovaries are capable of producing Active
Reproductive Cells (GAMETES) until PUBERTY.
THE MALE REPRODUCTIVE
SYSTEM
1. Males begin to produce Sperm during Puberty,
the adolescent stage of development when
changes in the body make reproduction possible.
 2. At this time, the concentration of the hormone
Testosterone is high enough to stimulate sperm
production. Testosterone is the Main Androgen
(Male Sex Hormone) produced by the Testes.
 3. The TESTES develop within the Abdominal
Cavity, just before birth the Testes descend
through a canal into an EXTERNAL SAC called
the SCROTUM.
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MALE REPRODUCTIVE SYSTEM
4. The Testes (two egg-shaped structures) remain
in the Scrotum, outside the body, where the
temperature is about 3 degrees C Cooler than the
body internal temperature (27 degrees C).
 5. Sperm development in the Testes Requires the
Lower Temperature.
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MALE REPRODUCTIVE SYSTEM
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6. The Testes are clusters of hundreds of Tiny Tubules
called SEMINIFEROUS (sehm-uh-NIHF-er-uhs)
TUBULES, which means "SEED BEARING". Sperm
Form through Meiosis in the specialized lining of this
extensive network of tubules.
7. As the Pituitary Gland begins to release FSH and LH,
these Hormones stimulate the Testes to make the
PRINCIPAL MALE SEX HORMONE TESTOSTERONE.
8. Cells that respond to Testosterone are found all over the
body.
9. Testosterone produces a number of SECONDARY SEX
CHARACTERISTICS that appear in Males at Puberty –
Voice Deepens, Beard Grows, and Body Hair.
MALE REPRODUCTIVE SYSTEM
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10. FSH and Testosterone stimulate the
development of Sperm. When large numbers of
sperm have been produced in the Testes, the
development process of Puberty is completed THE REPRODUCTIVE SYSTEM IS NOW
FUNCTIONAL.
SPERM DEVELOPMENT
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1. Sperm are derived from Special Cells within the Testes
that go through the process of MEIOSIS to form HAPLOID
NUCLEI found in Mature Sperm. The Chromosome
number drops from 46 to 23, Four sperm cells result from
each cell that begins meiosis.
2. A Mature Sperm consists of THREE Regions:
A. HEAD - which contains the Nucleus (The 23
Chromosomes) and enzymes that help the sperm penetrate
the protective layers that surround and Egg Cell.
B. MID PIECE - packed with energy releasing
Mitochondria (Energy Source). The Mitochondria supply
the energy that is required for sperm to reach an Egg.
C. TAIL – Consists of a Single, Powerful FLAGELLUM
that propels the Sperm.
MALE ANATOMY CONT. . .
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Sperm leave testes and travel through coiled ducts
emptying into a single tube called the EPIDIDYMUS
where they complete maturation
From the epididymus they go to the VAS DEFERNS
where they may be stored 2-3 months or until release
from the body.
VAS DEFERENS – duct that transports sperm
toward the ejaculatory ducts and urethra. Peristaltic
contractions force sperm along.
URETHRA- tube within the penis that transports
sperm out of the male body. Muscle at the base of the
bladder prevents URINE and sperm from mixing.
Where sperm form
Vas deferens
Bladder
Seminal
vesicle
Bladder
Vas deferens
Prostate
gland
Rectum
Urethra
Penis
Epididymis
Testis
Scrotum
Urethra
Bulbourethral
gland
Epididymis
Sperm-producing
tubes
Testis
Penis
MALE REPRODUCTIVE CONT…
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Fluids that help transport sperm are called
SEMEN:
SEMINAL VESICLES- base of bladder, pair of
glands that secrete mucous like fluid into the vas
deferens.
PROSTATE Gland- Located below urinary
bladder and top of the urethra. Secretes alkaline
fluid to help sperm move and survive.
 BULBOURETHRA Glands (2)- beneath prostate
that neutralize the acidic environment of male
urethra and female vagina.
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SECONDARY SEXUAL CHARACTERISTICS MALE
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Produced by testosterone
Deeper voice
 Chest and facial hair
 Lengthen bones
 Increased size of testes for sperm production
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PURPOSE OF FEMALE REPRODUCTIVE SYSTEM
Oogenesis
Nurture
egg
AP VIEW OF FEMALE REPRODUCTIVE
STRUCTURES
FEMALE ANATOMY
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Main function- production of eggs (female sex
cells) . To receive sperm and provide an
environment in which a fertilized egg can
develop.
Ovary(2)- place where eggs are produced. One on
each side of the lower abdomen. Almond size and
shape.
OVIDUCT (fallopian tubes)- tube that transports
eggs from the ovary to the uterus. Peristalsis of
muscles in wall of oviduct move eggs from ovary
to uterus along with beating cilia.
CONT…
Uterus- (womb)- between urinary bladder and
rectum and is the size of an inverted pear. 3
layers:
Outer layer- connective tissue
Middle layer- Thick muscle
Inner lining- ENDOMETRIUM
 Cervix- Lower end of the uterus, narrow and
opens into the vagina
 Vagina- passage out of the body.
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PUBERTY IN A FEMALE
Follicle Stimulating Hormone (FSH) stimulates
the development of follicles in the ovary.
 Follicle group of epithelial cells that surround a
developing egg. FSH stimulates the follicle and
estrogen release (Secondary sex characteristics).
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Males produce sperm from puberty until death.
At puberty a female has about 40,000 primary
oocytes (In meiosis I waiting to begin ). Oocytes
develop in utero (when female baby is still in
mom’s tummy)
EGG RELEASE
Egg Release:
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Once a month an egg will begin to divide and
a t Meiosis II it will rupture from the follicle and
be released into the oviduct= OVULATION.
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SECONDARY SEXUAL CHARACTERISTICS FEMALE
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Induced by increased LH, FSH, estrogen, and
progesterone hormone levels
Pubic hair
 Widen pelvis
 Enlarge mammary tissue (breasts)
 Begin menstrual cycles
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MENSTRUAL CYCLE- SERIES OF CHANGES IN A
FEMALE INCLUDING PRODUCTION 0F EGG AND
PREPARING THE UTERUS TO RECEIVE IT.
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Once the egg is released from the follicle the empty area
develops into the CORPUS LUTEUM which secretes
hormones called ESTROGEN and PROGESTERONE
which change the lining of the uterus.
This process only lasts 30-40 years after which
MENOPAUSE or a ceasing of the production of eggs occurs.
If the egg is not fertilized the lining of the uterus is shed
causing some bleeding for a few days .
3 phases:
Flow phase- days 1-6 sloughing off of uterus
 Follicular phase- days 6-14 secreting of estrogen and
progesterone to develops the egg.
 Luteal phase- days 14-28 ovulation occurs and corpus luteum
develops
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MENSTRUAL CYCLE
 The
Decrease in Levels of Estrogen and
Progesterone causes the Blood Vessels in
the uterine lining to begin closing and
then Break.
 The Cells of the Uterine lining DO NOT
receive adequate blood supply and come
loose from the inside of the uterus
 The mixture of Blood and the Cells that
made up the lining of the uterus is called
MENSTRUAL FLUID.
MENSTRUAL CYCLE
 The
passage of this Fluid through the
Vagina and out of the body is called
MENSTRUATION OR THE
MENSTRUAL PERIOD THE LAST
STAGE. IT USUALLY LASTS FROM
THREE TO SEVEN DAYS. At the end of
the Period, a NEW Cycle Begins- THE
FOLLICULAR PHASE.
 The AVERAGE Menstrual Cycle is 28
DAYS LONG.
MENSTRUAL PERIOD
Almost ALL Women START their Menstrual
Period 14 DAYS AFTER Ovulation occurs.
 The length of the First stage of the cycle, the
period when the Follicle is growing, DIFFERS
from women to women.
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DEVELOPMENT OF SEX CELLS
MENSTRUAL CYCLE AND HORMONE
LEVELS
FERTILIZATION
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After egg ruptures it is able to stay alive for
about 24 hours. For fertilization sperm must be
present in the oviduct at some point during those
first hours. Sperm delivered into the female at
one time range from 300-500- million and can live
48 hours so intercourse may occur from a few
days before ovulation
FERTILIZATION
3 Functions
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transmission of genes from parents
restoration of the diploid number
initiation of development
Steps
Capacitation
 Sperm-Zona Pellucida Binding
 Acrosome Reaction & Penetration
 Egg Activation & Cortical Reaction
 Zona Reaction
 Post-fertilization events
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Preembryonic Development
Bone Formation
THE EMBRYO TAKES SHAPE
EMBRYOLOGICAL DEVELOPMENT:
4 Major Tissues appear
early in embryo
development. 1st two
months after conception.
 After conception a series of
cell divisions begin. Single
celled zygote develops into a
hollow ball of cells called the
blastocyst.
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BLASTOCYST:
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Blastocyst implants in wall
of uterus within two weeks.
Cells regroup into 3 primary
germ layers: Endoderm,
Ectoderm and Mesoderm.
This process is called
gastrulation.
GERM LAYERS
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Ectoderm:
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Skin- epidermis
Ectoderm
Lining of mouth, anus, nostrils
Sweat and sebaceous glands
Epidermal derivations – hair and enamel of teeth
Nervous system- brain and spinal cord
Epithelial (sensory ) parts of eyes, nose, ears
MESODERM- MIDDLE
Muscles
 Skeleton (bones and cartilage)
 Blood
 Epithelial lining of blood vessels
 Dermis of skin and dentin of teeth
 Organs – except lining of the excretory and
reproductive systems
 Connective Tissue
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ENDODERM- INNER LAYER
Epithelium (lining) of digestive and respiratory
systems
 Secretory parts of liver and pancreas
 Urinary Bladder
 Epithelial lining of urethra
 Thyroid, parathyroid, thymus
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CHORIONIC VILLI
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Finger-like growths of the trophoblasts into the endometrium to
form the placenta.
PLACENTAL MAMMALS
GASTRULATION
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Preembryo becomes embryo as three primary germ
layers form.
Prembryo
Embryo
TRIPLOBLASTIC
LAYERS
Ectoderm
 Mesoderm
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Fetal Skeletons
Endoderm
Fetal Development
Fetal Development
At the 8th week, the embryo is called a FETUS
At 8 weeks
Embryo, approximately 8 weeks from conception
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DEVELOPMENTAL EVENTS-TABLE
28.2
FETAL TESTS
Ultrasound - sound waves are used to get an image of the baby
You can tell the sex of the baby and its position
Amniocentesis & Chorionic Villi Sampling
Tests fetal cells for abnormalities, such as
chromosome numbers
PLACENTA ABRUPTIO
Any amount of placental
separation prior to delivery.
 Causes & Risk Factors:
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Abdominal trauma
Hypertension during pregnancy
Diabetes mellitus
Cigarette smoking
Alcohol use during pregnancy
PLACENTA PREVIA
 Placental
growth across or
adjacent to opening of cervical
canal in the uterus.
 Risk Factors:
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The number of prior pregnancies
Multiple pregnancies
(twins/triplets)
Prior C-section where scar is close
to cervix
 Symptoms:
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Spotting during 1st & 2nd
trimesters
Sudden, painless & profuse
vaginal bleeding
ECTOPIC PREGNANCY
Implantation of blastocyst anywhere
other than within the uterus.
 Causes & Risk Factors:
 Physical blockage of uterine tube.
 Scarring of uterine tube by prior
tubal infection (pelvic inflammatory
disease).
 Pregnancy following tubal ligation
reversal or despite oral contraceptive
use.
 Symptoms:
 Lower abdominal or pelvic pain.
 Mild cramping on one side of pelvis.
 Abnormal vaginal bleeding
(spotting).
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LABOR
Contractions of muscles
occur and become
faster and faster, this
timing can be used to
predict the
progression of the
labor.
Braxton Hicks
contractions can
occur throughout
pregnancy, but
probably more
frequent at the end
Dilation of the cervix allows
for baby to pass through,
the amount of dilation also
is a good clue for how close
baby is.
An epidural can be used to manage pain of labor. A shot
in the spine will temporarily eliminate any feeling below
that point. Mom is awake for the birth, but doesn't have
the pain of it.
Unfortunately, an epidural must be timed exactly
right. Too soon and it will wear off. Too late, and they
cannot do the procedure.
PARTURITION
Stage 1 full cervical dilation
Latent, active, deceleration
Stage 2 delivery of infant
Stage 3  delivery of placenta
TERATOGEN
“MONSTER FORMING”
 Factors
that
may cause
severe
congenital
abnormalities
or fetal death
 alcohol,
nicotine, some
drugs,
German
measles
FETAL ALCOHOL SYNDROME
 Prenatal
&
postnatal growth
retardation
 CNS involvement:
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neurological
abnormalities
developmental delays
 Alcohol
related birth
defects
 Mental retardation
 Speech & hearing
impairment
 Learning, attention
& memory deficits
PLACENTAL FUNCTION - SMOKING
•Increases risk of
ectopic pregnancy
•Doubles risk of
placenta previa &
abruptio placenta
•Slows fetal
development
•Doubles risk of low
birthweight babies
•Increases risk of
preterm deliveries
•Increases risk of
cleft palate & lip
•Doubles risk of
sudden infant death
syndrome (SIDS)
CHANGES IN FETUS AND UTERUS
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BIRTH CONTROL:
BARRIER METHODS: CONDOM, SPONGE,
DIAPHRAGM
HORMONES- BIRTH CONTROL
PILL, IMPLANTS,
PATCHES
IUD
PERMANENT: TUBAL LIGATION, VASTECTOMY
PLAN B PILL- MORNING AFTER PILL. MUST BE
USED WITHIN 72 HOURS OF UNPROTECTED SEX,
IT PREVENTS THE EGG FROM RELEASING OR
THE SPERM FROM FERTILIZING THE EGG. IT
ALSO PREVENTS IMPLANTATION.
DOES NOT WORK IF YOU ARE ALREADY
PREGNANT
RESOURCES
Human Anatomy Reproduction Animations
 NOVA Online “Life’s Greatest Miracle”
 Craniopagus parasiticus Video
 Male Reproductive Histology
 Female Reproductive Histology
 The Biology of Sex
 Animal Fertilization & Cleavage
 A&P Lessons
 3D Medical Animations
 Fetal Development Timeline
 Egg & Sperm Anatomy
 Reproductive System Information
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