22 Reproductive
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22 Reproductive






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22 Reproductive 22 Reproductive Presentation Transcript

  • Ch. 22 Reproductive Systems
  • Specialized jobs of the Male Reproductive system: - produce and maintain the male sex cells - to transport these cells to the female - to secrete male sex hormones Primary sex organs (gonads) are the 2 testes - sperm cells are formed here - male sex hormones are formed Accessory sex organs - are the other structures of the male repro. system - internal reproductive organs - external reproductive organs
  • Male Reproductive Organs View slide
  • Male Reproductive Organs posterior view View slide
  • Descent of Testes Usually a month or two before birth, these organs descend to the lower abdominal cavity and pass through the abdominal wall into the scrotum. Gubernaculum
  • Structure of the Testis
  • Spermatogenesis
  • Meiosis
    • Includes two successive divisions
      • First meiotic division
        • Separates homologous chromosomes
      • Second meiotic division
        • Each cell emerges with one member of each homologous pair (haploid)
  • Meiosis I
    • Prophase I
      • chromosomes thicken, nulcear membrane disappears
      • Homologous chromosomes pair up side by side and intertwine ( synapsis )
    • Metaphase I
      • Chromosome pairs line up midway
    • Anaphase I
      • Homologous chromosome pairs separate (apart)
    • Telophase I
  • Crossing Over
    • mixes up traits
    • red is from Mom
    • green is from Dad
  • Meiosis II
    • Very similar to a mitotic division
    • Prophase II
    • Metaphase II
    • Anaphase II
    • Telophase II
      • Potential to produce 4 gametes
        • Males  4 sperm cells
        • Females  1 large cell; 3 polar bodies cast away (849)
  • Oogenesis
  • Crossing Over
    • the genetic information in sperm cells and egg cells varies from cell to cell
  • Structure of a Sperm Cell
  • Male Internal Accessory Organs
    • epididymis
    • vas deferens
    • seminal vesicle
    • prostate gland
    • bulbourethral glands
  • Epididymis
    • Promotes maturation of sperm cells
    • Stores sperm until ready to exit the body
  • Vas Deferens
    • muscular tube
    • about 45 cm
    • dilates into the ampulla near termination
    • extends from epididymis to ejaculatory duct
  • Seminal Vesicle
    • secretes fructose (energy for sperm)
    • secretes prostaglandins (for female contractions)
    • contents empty into ejaculatory duct
  • Prostate Gland
    • surrounds beginning of urethra, just inferior to the urinary bladder
    • secretes an alkaline fluid that neutralizes the sperm-cell containing fluid
    • secretion enhances motility of sperm cells
    • neutralizes the acidic secretions of the vagina
    • If swollen puts pressure on urethra, making it hard for urine or sperm to exit
  • Bulbourethral Gland
    • AKA Cowper’s gland
    • inferior to the prostate gland
    • secrete mucouslike fluid
    • lubricates the end of the penis
    • View Human Atlas (Prostate Cancer)
  • Semen
    • sperm cells
    • secretions of seminal vesicles, prostate gland, and bulbourethral glands
    • slightly alkaline (7.5)
    • prostaglandins
    • nutrients
    • 120 million sperm cells per milliliter (release 2-5 mL)
  • Male External Reproductive Organs
    • scrotum
    • penis
  • Scrotum
    • pouch of skin and subcutaneous tissue
    • dartos muscle – smooth muscle in subcutaneous tissue; contracts to cause wrinkling of the scrotum; relaxes to move away from the body
      • **Sperm are housed away from the body because they must be 5 ºF cooler in order to survive**
    • medial septum divides scrotum into two chambers
    • each chamber houses a testis and epididymis
  • Penis
    • 3 columns of erectile tissue
      • Pair of corpora cavernosa
      • Single corpus spongiosum
        • Urethra passes through this tissue
  • Hormonal Control of Male Reproductive Functions
    • Figure 22.17 hypothalamus controls maturation of sperm cells and development of male secondary sex characteristics
    • negative feedback controls concentration of testosterone
  • Hormonal Control of Male Reproductive Functions
    • hypothalamus controls maturation of sperm cells and development of male secondary sex characteristics
    • negative feedback controls concentration of testosterone
  • Actions of Testosterone
    • increased growth of body hair
    • sometimes decreased growth of scalp hair
    • enlargement of larynx and thickening of vocal cords
    • thickening of skin
    • increased muscular growth
    • thickening and strengthening of the bones
  • Organs of the Female Reproductive System
    • specialized to produce and maintain female sex cells
    • transport these cells to the site of fertilization
    • to provide a favorable environment for a developing offspring
    • to move the offspring to the outside
    • to produce female sex hormones
    • Primary sex organs (ovaries)
      • Produce eggs and sex hormones
    • Accessory sex organs
      • Internal and external reproductive organs
  • Transverse Section of Female Pelvic Cavity
  • Ovaries
    • Several ligaments help hold each ovary in position
    • Descend like the male testes do
    • Of the several million oocytes formed, only a million or so remain at birth and around 400,000 at puberty
    • Fewer than 400-500 will be released
  • Ovary Attachments
  • Oogenesis
  • Oogenesis
    • Distribution of the cytoplasm is unequal
      • Secondary oocyte
      • First polar body
    • If fertilized, the oocyte divides unequally to produce a tiny second polar body and a large fertilized egg cell or zygote
    • Will develop into an embryo (2 nd – 8 th weeks)
    • Polar bodies allow for production of an egg cell that has a massive amount of cytoplasm and organelles required to get through first few cell divisions
  • Ovulation
    • Release of an egg cell
    • Usually propelled to the opening of a nearby uterine tube
    • If it is not fertilized it degenerates
    • Watch Human Atlas Ectopic Pregnancy
  • Female Internal Accessory Organs
    • uterine (fallopian) tubes
    • uterus
    • vagina
  • Uterine (Fallopian) Tubes
    • Place egg should be fertilized!
    • Near each ovary, a uterine tube expands to form a funnel-shaped infundibulum
      • Partially encircles the ovary medially
      • Infundibulum bears a number of irregular, branched extension called fimbriae
      • Generally does not touch the ovary
        • One of the larger ovarian fimbria connects directly
  • Uterus
    • Receives the embryo that develops from an egg cell that has been fertilized and sustains its development
    • Hollow muscular organ, like an inverted pear
    • Usually bent forward over the urinary bladder
    • Upper 2/3 is the body
    • Lower 1/3 is the cervix
    • Layers of the uterine wall
      • Endometrium - inner lining
      • Myometrium - muscular layer; smooth muscle
      • Perimetrium - outer layer
  • Uterine Wall
  • Vagina
    • Fibromuscular tube about 9 cm long that extends from the uterus to the outside
    • Open channel for offspring during birth
    • Posterior to the urinary bladder and urethra & anterior to the rectum
  • Hormonal Control of Female Reproductive Functions
    • Figure 22.31 estrogens inhibit LH and FSH during most of the reproductive cycle
  • Effects of Estrogens
    • development of breasts and ductile system of the mammary glands
    • increased adipose tissue in breasts, thighs, and buttocks
    • increases vascularization of skin
  • Mammary Glands
  • Surgical Methods of Birth Control
  • Sexually Transmitted Diseases
    • silent infections
    • most are bacterial and can be cured
    • herpes, warts, and AIDS are viral and cannot be cured
    • many cause infertility
    • AIDS causes death
    • symptoms of STDs include
      • burning sensation during urination
      • pain in lower abdomen
      • fever or swollen glands
      • discharge from vagina or penis
      • pain, itch, or inflammation in genital or anal area
      • sores, blisters, bumps or rashes
      • itchy runny eyes
  • Terms to Know on Page 868
    • Amenorrhea
    • Endometritis (endometriosis)
    • Epididymitis
    • Hysterectomy
    • Mastitis
    • Ovariectomy
    • Orchiectomy
    • Prostatectomy
    • itis - means inflamed
    • ectomy - removal of an organ surgically