Reproductive Systems

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Reproductive Systems

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

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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.

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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.

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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)

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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

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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.

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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

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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.

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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.

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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

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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.

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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!

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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.

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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.

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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.

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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.

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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

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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.

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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.

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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

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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

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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

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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.

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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.

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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.

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Male Reproductive SystemDisorders of the Penis
and Scrotum

• Hydrocele Scrotal swelling due to abnormal
  accumulation of watery fluid.
• Causes congenital abnormality, trauma, infection

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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.

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