Human Reproduction

Reading

• Chapter 16
• Selected Images from Lecture

Puberty

• Female
  • 11 - 12 years
  • Influences
    • Nutrition - as nutrition increases the age of puberty decreases just as seen in domestic animals
    • Economic status - increased economic status is associated with increased nutrition and health care resulting in a decreased age of puberty
  • Trends over last century have been for a decrease in the age of puberty throughout the world
• Male
  • 13 - 14 years
  • Influences
    • Same as for females
  • Trends are the same as females but they are not as dramatic

Sexual Behavior

• Behaviors are similar to that seen in domestic animals with the exception of an estrus period
  • Males
    • seek out female
    • continually watching females to see if any are sending body language that they are interested in him
    • body posturing
  • Females
    • seek out interaction with males
    • touch males
    • make eye contact
    • stroke their hair

Anatomy and Physiology - Female and Male

• Female Structure

  ovary uterus fimbria infundibulum ostium ampulla

  isthmus utero-tubal junction uterus internal cervical os cervical canal external cervical os

  anterior vagina hymen posterior vagina labia majora labia minora Bartholin glands clitoris

• Male Structure
  

  testis tunica albuginea seminiferous tubules mediastinum rete testis scrotum tunica vaginalis pampiniform plexus tunica dartos gubernaculum

  vas efferentia epididymis vas deferens ampulla seminal vesicles body of prostate (no diseminate) Cowper's gland urethra

  pelvic urethral muscle bulbospongiosis muscle ischiocavernosus muscle corpus spongiosum corpus cavernosum glans penis prepuce (forskin)

Notable points - Female

• Bartholin's glands - secret the lubrication during intercourse also a possible source of human pheremones
• external cervical os - where Pap smear is taken from to diagnosis cervical cancer

Pheromones

• Possibly from Bartholin's gland
• Shown to be present in other primates
• Women in dorms cycle together

Vaginal Environment

• Normally acidic
• Changes
  • Infections
    • Yeast
    • Bacterial
  • Medications
  • Douches
  • Artifical lubricants

Cervix

• Some think this is a sperm storage site in human
• Sperm do survive up to 2 days
• Increase in cervical mucous at time of ovulation
  • Response to increased estrogen levels

Uterus

• Normal is simplex
• Abnormal
  • Bicornuate or septae uterus
    • Early delivery or spontaneous abortion
    • Uterus can not enlarge enough
  • Duplex

Ovary

• 400,000 oocytes at birth
• Decrease with age
• Between 40 - 50 years of age enter menopause

Notable points - Male

• penis is muscular vascular
• ejaculate is approx. 3 ml with 200 million sperm/ml.
• ejaculate coagulates upon ejaculation and then liquifies within 30 minutes

Prostate Gland in the Male

• Prostate gland hyperplasia
  • First growth at puberty
  • Second growth starts after age 25
  • Urinary symptoms don’t occur before age 40
    • 50% of men at 60 have symptoms
    • 90% of men at 70 - 80 have symptoms
  • Symptoms
    • a hesitant, interrupted, weak stream
    • urgency and leaking or dribbling
    • more frequent urination, especially at night
  • Treatment
    • 5 alpha reductase inhibitors
    • Minimal invasive procedures
    • Surgery

Menopause

• Begins at 40 - 55 years of age
• No follicles left to grow
  • No estrogen - causes symptoms
• Detection
  • Variable menstrual cycles
  • Behavior changes and physical changes
  • FSH increase
    • HMG (human menopausal gonadotropin)
• Hormonal Replacement (estrogen and progesterone)
• Relieves behavioral changes
• Cadiovascular benefits
• Calcium uptake increases

The Mestrual Cycle - 28 days

• Ovarian Changes
  • Follicular changes
    • FSH increases at start of menses
      • Recruitment - FSH triggers strart of a follicular wave
      • humans only have 1 follicular wave per cycle
    • Selection or Deviation
    • Dominance - only 1 dominant follicle in humans
    • takes 14 days for follicle to develop, become dominant and ovulate
  • Corpus luteum
    • forms following ovulation
    • produces both progesterone and estrogen in the human
    • regress on day 27-28 in response to the woman not being pregnant
      • secretion of HCG from human embryo needed to maintain the corpus luteum
• Anterior pituitary hormones
  • FSH
    • increases following menses
    • increases in response to the GnRH surge to trigger ovulation
    • rest of cycle it remains steady and low
  • LH
    • increases in response to the GnRH surge to trigger ovulation
    • directly triggers ovulation
• Ovarian hormones
  • estrogen (estradiol)
    • increases prior to ovulation
      • comes from the dominant follicle
      • triggers positive feedback on GnRH and gonadotropins to cause ovulation
    • also increases during luteal phase due to its secretion from the corpus luteum
      • during luteal phase it cause increased growth of the endometrium
    • decreases as corpus luteum regress
      • in combination with progesterone this causes menses
  • progesterone
    • comes from corpus luteum so increases with its growth beginning of days 14 or 15
      • along with estrogen causes growth of endometrium
    • decreases with regression of corpus luteum on days 27 - 28
      • in combination with estrogen, the decrease causes menses
• Phases of the mestrual cycle
  • follicular - days 0 - 14
  • luteal - days 14 - 28
  • menses - days 0 - 5
    • this overlaps with follicluar phase
    • sometimes this is separated from follicular phase and then follicular phase goes from days 5 - 14 but FSH increases at start of menses to trigger recruitment and the next follicular wave

Detection of Ovulation

• Basal body temperature
  • take in the morning before any physical activitiy
    • follicular phase - 97.6 to 97.8 C
    • luteal phase - >98 C
  • increase in temperature occurs when ovulation has occurred
  • temperature remains elevated until regression of CL
    • likely due to progesterone exposure
  • luteal phase is usually constant among women at 14 days but folliclular phase may vary alot causing the differences in the length of mestrual cycles
  • method good to predict when ovualtion will occur in next cycle but not good to time intercourse in current cycle as ovulation has already occurred
  • also good to detect failure of ovulation (no increase in temperature) or failure of corpus luteum (early decrease in temperature)
• Ovulatory Pain
  • Mittelschmerz (middle pain)
  • Day 12 - 16 after after start of menstration
  • Lasts 12 to 36 hours

Human Fertility

• Cummalitive pregnancy rate (after months of attempts)
  • 1 month - 25%
  • 6 months - 75%
  • 12 months - 88%
• Pregnancy
  • Most prolonged cycles are due to spontaneous abortion
  • 20% of pregnancies with early pregnancy test spontaneously abort
  • Numerous Problems
    • Time of intercourse - gamete aging
    • Chromosomal abnormalities

Infertility

• Primary Infertility
• Failure to conceive within 1 year if no previous pregnancy
• Secondary infertility
  • Failure to conceive within 6 months if at least one previous normal pregnancy
• Assumption
  • Adequate sexual contact or exposure
    

Adequate Contact or Exposure - Problems

• Male
  • Hypospadias
  • Uretha opens on bottom of penis
  • Penis size not important unless both male and female obese. May be a problem in penetration depth.
• Exposure (needed near ovulation)
  • Average is 2 to 3 times/week
  • Frequency decreases with length of relationship
  • Busy schedules
    • If intercourse only on weekends, unlikely to become pregnant
    • Delaying pregnancy into 30s increases problems

Age Associated Problems

• Male
  • Decreased fertility with age, but can occur into 70s
• Female
  • Rare if over 50
  • 10% of women who have conceived can no longer do so by age 35
  • If over 36 and fail to get pregnant within 6 months should seek evaluation and therapy as time is short.
    

Misconceptions and Considerations

• Coital position
  • Does not matter
• Laying in bed for 30 minutes
  • No scientific merit
• Douching after intercourse will not work as a contraceptive scheme
• Birth control pills
  • Long term exposure does not effect fertility
  • Often used to regulate cycles
  • First cycle after going off pill, there is a sight increase of double ovulations
• Adoption - anxiety can effect ovulation
  

Female Infertility

• Failure of follicular development or ovulation
• Tubal blockages and ectopic pregnancies
• Spontaneous abortion
  • Uterine or CL problems

Stimulating Follicular Growth and Ovulation

• Low dose estrogen
  • Don't produce enough estrogen for GnRH surge
• HCG
  • Inadequate LH surge
• Clomaphine Citrate - antiestrogen
  • Hypothalamus precieves low estrogen so GnRH increases
  • FSH and LH increase stimulating follicular growth
• Pergonal (HMG - FSH activity)
  • Stimulates more follicular development

Tubal Disease

• DES exposure
• Infections - blocked oviducts
  • Pelvic inflamatory disease
  • Chlamydia, Gonorrhea, Strep. and Staph. bacteria, mycoplasma, tuberculosis
  • Stop infection, tubual surgery or IVF
• Ectopic pregnancies
  • 1 in 90 - 120
  • In DES exposure, 1 in 20
  • Dangerous!!!
    • Pain
    • Spotting or discharge from vagina

Male Infertility

• Low sperm count
  • Normal 200 million/ml, 2-3 ml
  • Abnormal <20 million in ejaculate
    • Treatment
      • Scrotal temperature control
      • GnRH pumps?
      • In vitro fertilization
      • Intracytoplasmic Sperm Injection (ICSI)
        • Sperm or round spermatid
• Abnormal sperm
  • Treatment
    • Temperature control, IVF, ICSI

Sterilization

• Female
  • Tubal ligation
• Male
  • Vasectomy
• Reversal are now possible in some cases
  

Birth Control

• Female
  • "The Pill" - progesterone + estrogen
    • Prevents ovulation
  • Long term progesterone
    • Depoprovera
    • Norplants
  • IUD
  • Spermacides
• Male
  • Condom
  • New and in some countries
    • Testosterone
    • GnRH agonist
      

Erythroblastosis Fetalis

• Isoimunization of mother with foreign red blood cell (RBC) antigens
  • Human placenta is permeable to some proteins such as antibodies
  • The anti-red blood cell antibody crosses placenta and destroy fetal RBCs
  • RBC antigens
    • RH factor
    • Other minor RBC antigens
  • Conditions for isoimmunization
    • Fetus must have foreign RBC antigen
    • Mother must be negative for this antigen
    • Fetomaternal hemorrhage occurs at birth or spontaneous abortion (miscarriage)
      • From 0.1 to 30 ml of fetal blood enters maternal circulation
• Treatment
  • Test at first prenatal visit for Rh antigen
  • If RH negative and Father Rh positive or unkown
    • Retest at 28 weeks (don't see isoimmunization before this time)
      • Administer Rh-immune globulin
    • At birth if fetus Rh-postive also give it Rh-immune globulin

Reproductive Diseases

• Hepatitis B - self limiting, vaccination
• HIV - AIDS - treatment but no cure
• Syphilis - antibiotics
• Gonorrhea - antibiotics
• Genital Herpes - treatment but no cure
• Genital Warts - treatment, human papiloma virus (cervical cancer, but not the subtype that causes genital warts)
• Chlamydia - antibiotics, pelvic inflammatory disease

Review Quizzes