Reproductive Systems - PowerPoint PPT Presentation

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Reproductive Systems

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Reproductive Systems Some organisms reproduce asexually. Asexual reproduction offspring come from a single parent, producing clones of themselves. – PowerPoint PPT presentation

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Title: Reproductive Systems


1
Reproductive Systems
  • Some organisms reproduce asexually.
  • Asexual reproduction offspring come from a
    single parent, producing clones of themselves.

2
Reproductive Systems
  • Human reproduce sexually
  • Gametes sex cells
  • Male sperm
  • Female - ova
  • Male and female gametes fuse to form a zygote.
  • Zygote develops into new individual.

3
Common Structural and Functional Characteristics
between the Sexes
  • Common general structure and function can be
    identified between the systems in both sexes.
  • Systems adapted for development of sperm or ova
    followed by successful fertilization,
    development, and birth of offspring.
  • Sex hormones in both sexes important in
    development of secondary sexual characteristics
    and normal reproductive system activity.

This picture has nothing to do with the ppt I
just put it here to put a pic on this slide.
4
Male Reproductive System
  • Reproductive organs can be classified as
    essential or accessory.
  • Essential organs in men and women are called
    gonads.
  • Male gonads Testes produce male sex cells
    spermatozoa
  • Female gonads Ovaries produce female sex cells
    (Ova)

5
Male Reproductive System
  • Accessory organs include
  • Ducts epididymis (2), vas deferens (2),
    ejaculatory duct (2), and prostate gland
  • Supportive sex glands seminal vesicle (2),
    bulbourethral (Cowpers gland (2)), and prostate
    gland
  • External genitals scrotum and penis

6
Male Reproductive SystemTestes
  • Testes located in scrotum
  • Scrotum temp. is 1C cooler than normal body
    temp. (important for sperm production and
    survival)
  • Tunica albuginea a tough whitish membrane that
    surrounds each testis and enters the gland to
    divide it into lobules.
  • Seminiferous tubule long, coiled structure that
    forms the bulk of the testicular mass.
  • Interstitial cells Small specialized cells in
    the testes that secrete the male sex hormone,
    testosterone.

7
Male Reproductive SystemTestis Functions
  • Sperm production is called spermatogenesis
  • From puberty on, seminiferous tubules
    continuously form sperm.
  • Spermatogonia Sperm precursor cells
  • Before puberty, increase in by the process of
    mitotic cell division.
  • During puberty, follicle stimulating hormone
    (FSH) is released and spermatogonium divide and
    form a primary spermatocyte specialized cells
    that undergoes meiosis to ultimately form sperm.
  • Spermatocyte divide (meiosis) and form spermatids
    these cells have only half (23) the genetic
    material and half the chromosomes.
  • Each spermatocyte forms 4 sperm cells

8
Male Reproductive SystemSpermatozoa (sperm)
  • Spermatozoa Highly specialized cells.
  • All of the characteristics that a baby will
    inherit from the father are contained in the head
    of every sperm head.
  • Acrosome contains enzymes to assist sperm in
    penetration of ovum.
  • Mitochondria in the midpiece provide energy for
    movement.

9
Male Reproductive SystemProduction of
Testosterone
  • Interstitial cells create testosterone
  • Testosterone 3 functions
  • 1. It masculinizes, i.e. deeper voice, body
    hair, muscle growth.
  • 2. Promotes and maintains development of male
    accessory glands
  • 3. Stimulating effect on protein anabolism.
    Responsible for greater muscular development and
    strength of male.

10
Male Reproductive SystemReproductive Ducts
  • Ducts that sperm pass through after exiting the
    testes, until reaching the exterior of the body.
  • Sperm is formed in testes then pass through (in
    order)
  • Epididymis
  • Ductus (Vas) deferens
  • Ejaculatory duct
  • Urethra

11
Male Reproductive SystemReproductive Ducts
  • Epididymis a single, very tightly wound tube
    about 6m (20 feet) in length.
  • Sperm mature and develop ability to swim as they
    pass through here.

12
Male Reproductive SystemReproductive Ducts
  • Ductus (Vas) Deferens Thick, smooth, very
    muscular, and movable tube that permits sperm to
    exit from the epididymis and pass from the
    scrotal sac upward into the abdominal cavity.
  • Can be felt through scrotum!

13
Male Reproductive SystemReproductive Ducts
  • Ejaculatory Duct Duct formed by the joining of
    the vas deferens and the duct from the seminal
    vesicle that allows sperm to enter the urethra.
  • Urethra Genital duct that carries sperm to the
    exterior.

14
Male Reproductive SystemAccessory Sex Glands
  • Accessory Glands include
  • 2 seminal vesicles
  • Prostate gland
  • 2 bulbourethral (Cowpers) glands
  • Accessory glands responsible for contributing 95
    of secretions to semen.
  • Semen (Seminal Fluid) mixture of sperm and
    secretions of the accessory sex glands.
  • Seminiferous tubules contribute sperm and only 5
    of semen.
  • About 1 teaspoon of semen is ejaculated.
  • Each ml contains 100,000,000 sperm.
  • Semen is alkaline, protects sperm from acidic
    female reproductive tract.

15
Male Reproductive SystemAccessory Sex Glands
  • Seminal Vesicles contribute 60 of semen
    volume.
  • Secretions are yellowish, thick, and rich in
    fructose
  • Fructose provides energy to motile sperm.

16
Male Reproductive SystemAccessory Sex Glands
  • Prostate Gland secretes a fluid that
    constitutes about 30 of semen
  • Lies below the bladder.
  • Helps activate sperm maintain their motility.

17
Male Reproductive SystemAccessory Sex Glands
  • Bulbourethral Glands (Cowpers glands)
  • Located just below prostate
  • Mucus-like secretions lubricate penile portion of
    urethra
  • Contribute about 5 of semen

18
Male Reproductive SystemExternal Genitals
  • External reproductive organs (genitalia) consist
    of penis and scrotum
  • Penis When sexually aroused, becomes stiff
    erect by filling with blood, then can enter and
    deposit sperm into vagina during intercourse.
  • Consists of corpus spongiosum, corpora cavernosa,
    glans, foreskin.

19
Male Reproductive SystemExternal Genitals
  • Corpus spongiosum column of erectile tissue
    that surrounds urethra
  • Corpora cavernosa 2 columns of erectile tissue.
    Lie above urethra.
  • Glans distal end of shaft of penis
  • Foreskin a loose fitting, retractable casing
    located over glans of penis
  • Circumcision removal of foreskin.

20
Male Reproductive SystemDisorders
  • Infertility abnormally low ability to
    reproduce.
  • Sterility Complete inability to reproduce.
  • Both disorders involve an abnormally reduced
    capacity to deliver healthy sperm to female
    reproductive tract.
  • Decrease in production of sperm
  • Structural abnormalities in sperm
  • Obstruction of reproductive ducts

21
Male Reproductive SystemDisorders of the Testes
  • Oligospermia decreased sperm production.
  • Leading cause of infertility.
  • Infection, fever, radiation, malnutrition, high
    temperatures
  • Cryptorchidism when testes do not drop from
    abdominal cavity into scrotum about 2 months
    before birth.
  • Must be treated b/c higher temperatures will
    permanently inhibit spermatogenesis.
  • Caused by hormonal imbalance, physical deficiency
    or obstruction.
  • Treated with hormone therapy or surgery

22
Male Reproductive SystemDisorders of the Testes
  • Testicular Cancer Most cancers of testes arise
    form sperm producing seminiferous tubules.
  • Most common 25 35 yr old.
  • Associated w/ genetic predisposition, trauma
    infection of testes, and cryptorchidism.
  • Early diagnosis is key to treatment

23
Male Reproductive SystemDisorders of the Prostate
  • Benign Prostatic Hypertrophy Enlargement
    (hypertrophy) of the prostate.
  • Common problem in older men.
  • As prostate enlarges, it squeezes the urethra,
    making urination difficult or impossible.
  • Treatment Prostatectomy Partial or complete
    removal of prostate.
  • Cancerous prostate growth causes similar symptoms
  • Treatment includes chemotherapy, cryotherapy,
    microwave therapy, hormonal therapy, radiation.

24
Male Reproductive SystemDisorders of the Penis
and Scrotum
  • Phimosis condition in which foreskin fits so
    tightly over the glans that it cannot retract
  • Severe Can obstruct urine flow causing death in
    infants.
  • Mild accumulation of dirt organic matter
    causing infection.
  • Treatment circumcision.

25
Male Reproductive SystemDisorders of the Penis
and Scrotum
  • Impotence Failure to achieve erection
  • May cause infertility due to inability to have
    intercourse.
  • Causes Anxiety, stress, abnormality of erectile
    tissues, failure of nerve reflexes that control
    erection, drug and alcohol use.

26
Male Reproductive SystemDisorders of the Penis
and Scrotum
  • Hydrocele Scrotal swelling due to abnormal
    accumulation of watery fluid.
  • Causes congenital abnormality, trauma, infection

27
Male Reproductive SystemDisorders of the Penis
and Scrotum
  • Inguinal Hernia Swelling of the scrotum due to
    protrusion of abdominopelvic organs through the
    inguinal canal and into the scrotum.
  • Intestines in scrotum may cause obstruction of
    digestive tract resulting in death.
  • Causes congenital, lifting heavy objects
  • Treatment surgery or external support.

28
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