Reproductive System UND

• Gonads


  • External
• Scrotum


  • Pouch that houses testes, distance from body will vary due to temperature for viable sperm
• Cremaster muscle


  • Elevates, sexual arousal or if cold
• Testes


  • Site of sperm production
• Parts of testes


  • Tunic - hard, outer protective coat
  • Septum - separates
  • Lobule - compartments within testes
  • Seminiferous tubules - tubules within lobule, where sperm is developed (spermatogenesis)
  • Straight tubule - passageway for sperm
  • Rete testis - passageway for sperm
  • Efferent ducts - passageway for sperm
  • Epididymis - passageway for sperm, maturing of sperm
• Testosterone


  Matures testes, develops sperm, sexual drive, lowers voice, broadens shoulders, narrows hips, muscular development, hair patterns and balding
• Ductus (Vas) deferens


  • Passageway for sperm
• Ejaculatory duct


  • Eject sperm into urethra
• Urethra


  • Transport vessel for urine and semen
• Accessory glands


  • Seminal vesicles - 60% of ejaculate, neutralizes acid, sperm motility
  • Prostate gland - 30% of ejaculate, contributes to sperm motility and viability
  • Bulbourethral (Cowper's) gland - neutralizes urine in urethra, lubricates end of penis
• Semen (seminal fluid)


  2.5 to 5.0 mL per ejaculation, includes all sperm and all combined materials
• Sperm characteristics


  • Numbers - produce 300 million a day, 150 million in ejaculate, <20 million infertile threshold
  • Life expectancy - 48 hours
  • Head - anterior region
  • Acrosome - enzymes to penetrate egg wall
  • Nucleus - contains the chromosomes
  • Chromosomes - 23, haploid #, ½ from father
  • Midpiece - middle region
  • Mitochondria - energy for locomotion
  • Flagellum - tail for locomotion
• Penis


  • Mechanism to transfer sperm
• Parts of penis


  • Glans - tip, for sensory and stimulation
  • Corpora cavernosa - 2 tubes
  • Corpus spongiosum - 1 tube, houses urethra
• Erection


  Arteries dilate, veins compress, blood pools in penis
• Ovaries


  • Internal
• Broad ligament


  • For support of ovaries
• Ovarian (Menstrual) cycle


  1. Hypothalamus - gonadotropin releasing factor (GnRF)

  2. Anterior pituitary gland - follicle stimulating hormone (FSH) - enlarges ovaries @ puberty

  3. Primary follicles - 1st stage of maturing oocyte, as many as 20 mature follicles, one dominant outgrows the others, the remaining will degenerate

  4. Secondary follicles - 2nd stage of maturing oocyte

  5. Graafian follicles - mature follicle, blister like

  6. Anterior pituitary gland - luteinizing hormone (LH) - triggers ovulation, swells follicle (blister like), weakens walls

  7. Ovulation - release of egg (ovum), the blister breaks / pops

  8. Corpus luteum - temporary glandular structure "yellow body", degenerates' day 24

  9. Estrogen - inhibits the release of LH and FSH, no other follicles are stimulated to grow

  10. Progesterone - makes the endometrium more vascular / glandular, inhibits the release of LH and FSH, no other follicles are stimulated to grow
• If fertilization does not occur


  1. Corpus albicans - little scar

  2. Low levels of estro/progest

  3. Breakdown of endometrium

  4. Hypothalamus secretes gonadotropin releasing factor (GnRF)

  5. Repeat of cycle
• If fertilization does occur


  1. Corpus luteum

  2. High levels of estro/progest - development of embryonic membranes and mucus plug in cervix, increase in blood supply, lactating tissue

  3. Relaxin - cervix/vagina and pubis symphysis

  4. Pituitary gland - oxytocin (OT) - contraction of smooth muscle of uterus during labor and contraction of breast tissue

  5. Pituitary gland - prolactin (PRL) - development of milk
• Fallopian tubes


  • Transport of egg and site of fertilization
• Parts of fallopian tube


  • Isthmus - where the fallopian tube attaches to uterus
  • Ampulla - middle region
  • Infundibulum - later expanded end
  • Fimbriae - finger like structure, draw egg(s) into the lumen of fallopian tube
• Uterus


  • Where fetus develops
• Parts of uterus


  • Fundus - superior
  • Body - middle
  • Cervix - inferior/narrow
  • Perimetrium - outer / superficial, protective
  • Myometrium - middle / muscular layer - active during labor
  • Endometrium - deep / inner layer / lining, attachment of embryo
  • Uterine cavity - space inside uterus, passageway (egg, sperm), fetus develop, attachment of embryonic membranes, menstrual cycle
  • Cervical canal - passageway (egg/sperm/menses), barrier (vagina/uterus), birth canal
• Vagina


  • Birth canal
• Clitoris


  • Stimulation
• Egg (ovum) (oocyte vs. follicle) characteristics


  • Numbers - 1 per month, ovaries alternate
  • Life expectancy - 48 hours
  • Oogenesis - egg cell formation
  • Haploid number - 23, ½ genetic information from mother
• Mammary glands


  • Lobes - compartments
  • Alveoli - milk secretion cells
  • Nipple - ducts terminate
  • Areola - pigmented area around nipple
• Menstrual cycle


  1. Average - 28 days

  2. Menses - days 1 à 5, sloughing of endometrium

  3. Preovulatory phase - days 5 à 14 build-ups of endometrium

  4. Ovulation - day 14 à release of egg

  5. Postovulatory phase - days 14 à 28 maintenance of endometrium
• Prenatal period


  Begins at fertilization, ends at birth, 3 shorter periods: pre-embryonic, embryonic, fetal
• Pre-embryonic period


  1. Fertilization

  2. Zygote

  3. Cleavage

  4. Blastocyst formation

  5. Implantation

  6. Trophoblast and embryoblast formation

  7. Extraembryonic membrane formation
• Embryonic period


  • Gastrulation, formation of 3 germ layers, organogenesis, sensitive to teratogens
• Fetal period


  9 weeks to birth, maturation of tissues and organs, rapid growth
• Course of pregnancy


  1st trimester: zygote to embryo to fetus

  2nd trimester: growth of fetus, expansion of maternal tissues

  3rd trimester: rapid growth/weight gain of fetus, mother's body prepares for labor/delivery
• Hormonal changes during pregnancy


  • hCG
  • Estrogen
  • Progesterone
  • Relaxin
  • CRH
  • HCT
  • HPL
• Other changes during pregnancy


  Uterine and mammary changes, digestive/nutrient/metabolic changes, cardiovascular/respiratory changes, urinary changes
• Labor


  Factors leading to labor

  False labor (Braxton-Hicks contractions)

  True labor (contractions increase, cervix changes)

  Stages of labor: dilation, expulsion, placental
• Postnatal changes to newborn


  Lungs, heart, separation of right and left sides
• Postnatal changes to mother


  Hormonal changes, "baby blues", hair loss, respiratory/blood/lactation/uterine changes
• Heredity


  Parent to child