Transcript Reproductive

Anatomy &
Physiology
Unit 12: Urogenital System
Male Anatomy
 Testicles: 2 per male-located within the
scrotum for temperature control
 Have 2 functions:

1. Endocrine function: making
testosterone
 Interstitial
cells: distinct cells that produce
testosterone
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2. Exocrine function: producing sperm
Male Anatomy
 Sperm Producing Structures (within
testicles)
1. Seminiferous tubules
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Tubes coiled together to form lobules in
the testes
“Sperm-forming factories”
2. Rete testes
receives sperm from seminiferous
tubules
Male Anatomy
 Sperm Producing Structures (within
testicles)
3. Epidydimus
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Highly coiled, 20 ft. tube
Sperm stay here for 20 days to mature
Will contract w/ stimulation to expel
sperm
Male Anatomy
 Sperm Producing Structures (within
testicles)
4. Vas (ductus) Deferens
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Functions to propel sperm from storage to
urethra
Runs from testes to pelvic cavity
Enclosed in spermatic cord with blood
vessels—empties into ejaculatory duct
Vasectomy: small incision through
scrotum to close off vas deferens
Male Anatomy
5. Urethra
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Runs from base of bladder to tip of penis
Function: transports urine and semen
Bladder sphincter closes upon ejaculation
so no urine is expelled and no semen
enters the bladder
Male Accessory Organs
 All contribute to the contents of semen
 Semen:
Milky, white and somewhat sticky
 Provides a transport medium & nutrients;
contains chemicals to protect the sperm
 Alkaline to protect sperm against acidity of
vagina
**sperm cannot swim in acidic environments

Male Accessory Organs
1. Seminal Vesicles
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Produces ~ 60% of fluid volume of
semen
Full of vitamin C and sugar to nourish
sperm
2. Prostate Gland
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Gland below the bladder which surrounds
the urethra
Adds a milky fluid to semen which helps
activate the sperm
Male Accessory Organs
3. Bulbourethral Gland
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Pea-sized gland
Produces the pre-ejaculate: clear and
thick mucus that flushes through the
urethra with stimulation, cleaning away
acidic urine; also a lubricant
Male Anatomy: External
Genitalia
1. Scrotum: a divided sac hanging
outside abdominal cavity
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Holds testicles
Can adjust location to be closer to body
when cold, and further when hot
Sperm only produced when at a
temperature 3 degrees cooler than body
temperature
Male Anatomy: External
Genitalia
2. Penis: designed to deliver sperm into
female; consists of:
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A shaft
Glans penis: the tip covered by prepuce
(foreskin)
Internally is the urethra and erectile tissue
Erectile tissue fills with blood during an
erection
Female Anatomy
 Ovaries: 2 small glands located in
pelvic cavity
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Endocrine Functions: produce estrogen
and progesterone
Exocrine Functions: make ova (eggs)
Female Anatomy

1.
Ova Producing Structures: within ovaries
Ovarian Follicles: tiny sacs that hold oocytes
(immature eggs)
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2.
3.
Surrounded by follicle cells
Oocyte will mature here
Graafian Follicles: a mature egg which is
ready to be ejected from the ovary during
ovulation
Corpus Luteum: the ruptured follicle after
ovulation

Usually degenerates unless fertilized
Female Anatomy
 Duct System
1. Uterine (Fallopian) Tubes
 Receives an ovulated oocyte and
provides a site for fertilization
 Does not actually come in contact with
ovary
 Fimbrae: finger-like projections which
wave to create a fluid current to direct
oocyte to fallopian tubes
Female Anatomy
 Duct System
2. Uterus (the womb)
 Hollow organ that receives, retains and
nourishes a fertilized egg
 Size of a pear in women who have not
been pregnant
 Cervix: narrow outlet of uterus
Female Anatomy
 Uterus Continued
 There are 3 layers to the walls of the
uterus
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Endometrium: the inner mucosa layer of
uterus where fertilized egg burrows into
and resides during development
(implantation)
Myometrium: the muscular, middle layer
which contracts during labor
Epimetrium: the outermost layer of uterus
Female Anatomy
 Duct System
3. Vagina (birth canal)
 Thin walled tube, ~ 3-4 inches long
 Provides a passageway for the delivery
of an infant and for menstrual flow to
leave body
Female Anatomy: External
Genitalia
1.
2.
3.
4.
5.
6.
Mons Pubis: fat pad over pubic bone
Labia Majora: large folds of skin
Labia Minora: smaller, more interior folds of
skin
Clitoris: erectile tissue anterior to labia
minora junction
Urethra: opening located between clitoris and
vaginal opening
Perineum: area of skin between vaginal
opening and anus
1.
Episiotomy: the surgical cutting of perineum
during childbirth
The Menstrual Cycle
 On average, takes about 28 days
 3 stages
1. Menses (days 1-5)
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thick endomerial wall detaching from
uterus
causes 3-5 days of menstrual flow
(bleeding)
The Menstrual Cycle
2. Proliferative Stage (days 6-14)
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endometrial wall repaired and blood
supply increased in response to rising
estrogen levels
vvulation occurs on day 14 because of
spike of blood LH levels
The Menstrual Cycle
3. Secretory Stage (days 15-28)
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endometrial gland secretion increases
nutrients within uterus
progesterone levels high
fertilization causes embryo to produce
hormone which maintains endometrial
lining
no fertilization causes endometrial blood
vessels to end its supply
menses occurs at day 28
Fertilization
 The egg: only viable for 12-24 hours
post-ovulation
 The sperm: can remain fertile in female
tract for 12-48 hours (sometimes up to
72 hours)
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Are attracted to chemical signals from the
egg
For fertilization to occur intercourse must
happen 72 hours before ovulation or within
24 hours after
Fertilization
 When the sperm reaches the oocyte:
acrosomes rupture releasing enzymes to
break away surrounding of oocyte
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First sperm in WINS!
Embryonic and Fetal
Development
 The zygote: the first cell created from
fertilization
 Cleavage: early stage of embryonic
development
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Rapid mitotic divisions occur as embryo
moves toward uterus
 Morula: a solid ball of cells
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Enters uterus around days 5-6
Embryonic and Fetal
Development
 Blastocyst: 100 cell embryo
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Hollowed out and filled with fluid
Free floats in uterus
Secrets human chorionic gonadoptropin
(hCG)
hCG tells corpus luteum to keep up
hormone production
**hCG hormone in urine used to detect
pregnancies
Embryonic and Fetal
Development
 By Day 7: late blastocyst stage
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Starts uterine attachment—embeds into
endometrium
Cells start re-arranging themselves
1.
2.
trophoblast: the fluid filled sphere
Inner cell mass: small cluster of cells
displace to one side
Embryonic and Fetal
Development
 Once placenta has formed (functional
by third week) the mom’s blood supply is
now connected to the babies via the
umbilical cord
 Nutrients are fed into the amnion (fluid
filled sac) where baby develops
Embryonic and Fetal
Development
 Germ Layers form next (3)
1. Ectoderm: make up the nervous
system and skin
2. Endoderm: forms mucosa and glands
3. Mesoderm: forms all else (muscles,
bones, etc.)
Embryonic and Fetal
Development
 Week 3: placenta functions—delivers
nutrients, disposes of wastes
 Week 8: placenta making progesterone
and estrogen to help maintain pregnancy
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Organ systems groundwork established
 Week 9: now a fetus
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Growth and organ specialization
Body proportions develop
Embryonic and Fetal
Development
 12 weeks: sex is discernable
 Month 4: looks human
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Can suck lips and blink eyes
 Month 5: limbs near full-size
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More muscular activity from baby
 Months 6 & 7
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Weight increase
Eyes open
The Mom
 Anatomical Changes:
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Uterus crowds abdominal cavity
Center of gravity changes
Lumbar lordosis = back pain
Relaxin causes pelvis to expand (ligaments
relax)
Needs 300 extra calories daily
The Mom
 Physiological Changes
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Morning sickness due to hormonal changes
Heartburn because of displacement of esophagus
Frequent and urgent urination—incontinence
Nasal stuffiness (estrogen)
VC increases –dyspnea
Blood volume increases 25-40%
Varicose veins
Parturition aka childbirth
 Occurs ~ 280 days after last menstrual period
 Labor: series of events that expel infant from
uterus
 Triggers to induce labor:
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High estrogen and low progesterone
Braxton Hicks: weak contractions aka false labor
False labor becomes actual labor when oxytocin
and prostaglandins are released
Parturition aka childbirth
 3 stages of labor:
 Stage 1: Dilation
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From true contractions to full dilation of
cervix (10 cm.)
Contractions move in waves from superior
uterus inferiorly
Amnion ruptures (water breaks)
Parturition aka childbirth
 Stage 2: Expulsion Stage
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From full dilation to delivery
Can take from 20 mins. to 2 hours
Baby should exit head first
Buttocks first is called breech
Parturition aka childbirth
 Stage 3: Placental Stage
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Delivery of placenta
Occurs within 15 minutes of birth
Uterine contractions decrease bleeding
and afterbirth can be removed with a tug
of the umbilical cord