The Human Reproductive System

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The Human Reproductive System
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Male Reproductive System
urinary bladder
seminal vesicles
prostate gland
urethra
penis
rectum
epididymis
Cowpers gland
testis/testes
vas deferens
scrotum
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Male Reproductive System (frontal view)
See p. 62 in Review book
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Male Reproductive System

• Scrotum sac of skin that holds testes. Hangs
  below body to keep testes cool. Sperm cannot be
  produced if body is too warm. Testes move into
  scrotum just before birth.
• Testis/testes male gonads. Made up of small,
  coiled tubes seminiferous tubules. 300-600 per
  testis. Immature sperm made here.
• Secrete testosterone

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Male Reproductive System

• Epididymis storage area in upper rear of
  testis. Immature sperm move here to mature
  takes 18 hours.
• Vas deferens tube that leads upwards from each
  testis into lower part of abdomen from
  epididymis.
• Cowpers gland produces fluids that nourish
  sperm and protect them from the acidity of
  female.
• Combination of sperm and fluids - semen

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Male Reproductive System

• 6. Rectum holds wastes
• 7. Seminal vesicles same job as Cowpers gland
• 8. Urinary bladder stores urine
• 9. Prostate gland same job as Cowpers gland
  and seminal vesicles
• 10. Urethra passageway for excretion of urine
  and for sperm to leave body. Vas deferens
  empties into urethra

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Male Reproductive System

• 11. Penis male reproductive organ. Facilitates
  internal fertilization
• Ejaculation muscular contractions force semen
  through urethra. Before, during and after
  ejaculation reflex actions keep outlet of bladder
  closed

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Hormones and Negative Feedback in Males

• Negative Feedback change that leads to a
  response that causes something to counteract that
  change
• Luteinizing Hormone (LH) stimulates testes to
  produce testosterone
• Testosterone stimulates development of sperm.
  Once there is a large number of sperm, puberty is
  complete.

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Hormone Negative Feedback System
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• What is the effect of high levels of LH?
• Testosterone is produced
• What is the effect of high levels of
  testosterone?
• Slows production of LH which in turn slows
  production of testosterone
• What is the overall outcome of this on-off
  negative feedback system involving LH and
  testosterone?
• Nearly constant level of both hormones -
  homeostasis

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Another Way of Looking at Negative Feedback in
the Male Reproductive System
Brain
Pituitary gland
Male Reproductive Organs
target cells receptor cells
LH stimulates the testes cells
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Male Reproductive System and Hormones

• Explain how LH stimulates the testes to produce
  testosterone.
• Circulates in the blood- reaches the testes
  target cells stimulates them to produce
  testosterone
• What happens when the levels of testosterone are
  too high in the body?
• LH level drops
• What is negative feedback and how does it
  maintain homeostasis?
• Change in conditions triggers response in body
  to counteract that condition. Keeps hormones in
  balance

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Female Reproductive System
oviduct
ovary
Urinary bladder
uterus
urethra
rectum
cervix
vagina
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Female Reproductive System (frontal view)
See p. 61 in Review book
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Female Reproductive System

• Ovary female gonads. Secrete estrogen
  produces secondary characteristics, menstrual
  cycle
• Produces eggs 2 ovaries 4cms long, 2 cms
  wide

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• Follicles each ovary contains 200,000 egg sacs
  called follicles. In each follicle is an
  immature egg.
• All the eggs are present at birth. During the
  womans lifetime 500 eggs mature
• When an egg matures, follicle moves to surface
  of ovary.
• Follicle breaks releases the egg ovulation
• Egg can be fertilized for about 24 hours after
  ovulation

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Female Reproductive System

• 2. Oviduct (fallopian tube) Each ovary is near
  but not connected to oviduct. Tube with
  funnel-like opening. Cilia line it to create a
  current that draws the egg into the tube. Egg is
  fertilized in the oviduct
• 3. Uterus thick, muscular, pear-shaped organ.
  Once egg is fertilized it finishes its
  development in uterus attached to uterine wall

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Female Reproductive System

• 4. Urinary bladder storage of urine
• 5. Urethra passage of urine to outside of body
• 6. Vagina (birth canal) leads to outside of
  body
• 7. Cervix narrow neck of uterus
• 8. Rectum passage for wastes

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The Menstrual Cycle

• What is the menstrual cycle?
• Cycle during which an egg develops and is
  released from the ovary and the uterus is
  prepared to receive a fertilized egg
• Menarche first menstrual period usually occurs
  between 11 and 12
• Menopause time when a woman stops menstruating,
  usually between 45 55 and is no longer able to
  conceive.

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The Menstrual Cycle
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The Menstrual Cycle

• 1. Menstruation Loss of egg and uterine tissue
  via vagina if fertilization does not occur
• 2. Follicle Stage (follicular stage) lasts 10
  days, FSH LH levels increase, egg matures,
  follicle secretes estrogen to prepare uterus

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The Menstrual Cycle

• 3. Ovulation High level of estrogen detected by
  hypothalamus, increased LH, decreased FSH,
  follicle bursts egg released
• 4. Corpus Luteum Stage (Luteal Phase) LH
  converts follicle to corpus luteum secretes
  estrogen progesterone. Progesterone prepares
  uterus. Increased progesterone keeps LH FSH
  low

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Another Way of Looking at Negative Feedback in
the Female Reproductive System (Hormones of the
Menstrual Cycle)
Brain
Pituitary gland
FSH (causes egg to mature in follicle)
LH (causes to egg to be let go ovulation)
ovary
Estrogen (causes uterine lining to thicken
build up to prepare for egg)
uterus
Progesterone (helps maintain uterine lining)
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Hormones of Menstrual Cycle

• What happens if fertilization occurs?
• Corpus luteum keeps producing progesterone to
  maintain pregnancy. After 5 weeks the embryo
  produces progesterone this inhibits LH FSH so
  no menstrual cycle
• What happens if fertilization does not occur?
• There is no implantation the corpus luteum
  breaks down. Progesterone level drops, uterine
  lining breaks down menstruation.
• FSH LH are produced again new cycle
• Average Menstrual Cycle is 28 days long

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Ovulation to Implantation
oviduct
uterus
egg from ruptured follicle
ovary
cervix
follicle
vagina
sperm
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Ovulation to Implantation

• Ovary produces estrogen progesterone
  meiosis occurs egg develops
• Egg matures in follicle of ovary
• Ovulation egg released from follicle may live
  for 24 hours
• - egg moves into fallopian tube by cilia

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Ovulation to Implantation

• Events in fallopian tube
• Fertilization occurs here. Sperm lives 4-5 days
  (egg lives 1 day)
• Zygote undergoes mitosis travels down fallopian
  tube within 6-10 days. Zygote is ready to
  implant into uterus.

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Ovulation to Implantation

• Events in uterus
• Implantation embryo implants/embeds into
  uterine lining secretes hormone HCG to signal
  its arrival
• Cell Differentiation cells divide by mitosis
  become different due to gene expression.
  Different embryo parts will form.

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• Menstrual Cycle Animation

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Sexually Transmitted Diseases (STDs)

• Definition Disease spread from one person to
  another during sexual contact
• Types of STDs gonorrhea, chlamydia, syphilis,
  genital herpes, HIV, trichomonas
• Reducing Risky Behavior
• a. Avoid sexual contact
• b. Avoid intravenous drug use

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Child with gonorrheal infection in the eyes
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Advanced syphilis
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Genital herpes
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Trichomonas Life Cycle
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Birth control
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Birth Control
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Birth Control