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The Human Reproductive System

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The Human Reproductive System Male Reproductive System scrotum testis/testes epididymis vas deferens Cowper s gland rectum seminal vesicles urinary bladder prostate ... – PowerPoint PPT presentation

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Title: The Human Reproductive System


1
The Human Reproductive System
2
Male Reproductive System
urinary bladder
seminal vesicles
prostate gland
urethra
penis
rectum
epididymis
Cowpers gland
testis/testes
vas deferens
scrotum
3
Male Reproductive System (frontal view)
See p. 62 in Review book
4
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

5
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

6
Male Reproductive System
  • 6. Rectum holds wastes
  • 7. Seminal vesicles secretes liquid that
    extends sperm life including fructose
  • 8. Urinary bladder stores urine
  • 9. Prostate gland controls flow of urine
    secretes alkaline solution.
  • 10. Urethra passageway for excretion of urine
    and for sperm to leave body. Vas deferens
    empties into urethra

7
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

8
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.

9
Hormone Negative Feedback System
10
  • 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

11
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

12
Female Reproductive System
oviduct
ovary
Urinary bladder
uterus
urethra
rectum
cervix
vagina
13
Female Reproductive System (frontal view)
See p. 61 in Review book
14
Female Reproductive System
  • Ovary female gonads. Secrete estrogen
    produces secondary characteristics, menstrual
    cycle
  • Produces eggs 2 ovaries 4cms long, 2 cms
    wide

15
  • 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

16
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

17
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

18
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.

19
The Menstrual Cycle
20
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

21
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

22
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

23
Ovulation to Implantation
oviduct
uterus
egg from ruptured follicle
ovary
cervix
follicle
vagina
sperm
24
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

25
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.

26
End of Presentation
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