Reproduction and Development

1. Establish the genetic and hormonal basis for sex determination.
2. Review the anatomy of the male and female reproductive systems.
3. Discuss how hormones regulate sexual maturation and gonadal function in males and females.
4. Explain the timing and hormonal regulation of the menstrual cycle.
5. Discuss the process of implantation.
6. Describe the structure and physiology of the placenta.
7. Explain the fetal-maternal interactions that occur during pregnancy.
8. Describe some of the unique aspects of fetal physiology.
9. Discuss the hormonal and neural processes that control birth and lactation.
10. How effective are various contraceptive methods?

LECTURE OUTLINE

I. INTRODUCTION TO REPRODUCTION  

  A. General functions of the reproductive system
  B. Complex hormonal interactions regulate the reproductive system

II.  SEXUAL DIFFERENTIATION

  A. Meiosis is the change from diploid to haploid cells
     1. Fertilization of ovum by sperm re-establishes diploid
         state 
     2. Human karyotype: Sex chromosomes (XX and XY)
  B. Role of the Y chromosome
     1. Nondisjunction during meiosis
     2. Evidence: Klinefelter's Syndrome and other nondisjunctions  
  C. How does the Y chromosome determine male sexual differentiation?
     1. Male is XY; Female is XX
     2. Sex determining Region of the Y (SRY) stimulates H-Y
         antigen 
     3. H-Y antigen stimulates testes development
     4. Three hormones develop the reproductive system
          a. Mullerian-inhibiting factor (MIF =Anti-Mullerian Hormone)
          b. Testosterone (T) stimulates internal genitalia
          c. Dihydrotestosterone (DHT) stimulates external genitalia
     5. Default state at any point results in the female developmental pattern
     6. Summary of events
   
III.  MALE REPRODUCTIVE PHYSIOLOGY

  A. Testes Structure and Function
     1. Seminiferous tubules
     2. Sertoli cell functions
          a. Function of Inhibin
     3. Leydig cells secrete Testosterone (T)
          a. Functions of T 
  B. Regulation of Testes Function (HPG axis)
     1. Role of GnRH initiates puberty
          a.  Structure/function of the GnRh neuron
          b.  Importance of pulsatile GnRH secretion
     2. GnRH action at anterior pituitary: Release FSH and LH
     3. FSH and LH target the testes
         a. FSH increases spermatogenesis
         b. LH stimulates interstitial cells to release T, etc.
     4. Feedback: T and Inhibin inhibit hypothalamus and/or pituitary  

IV.  FEMALE REPRODUCTIVE PHYSIOLOGY  

  A. Female reproductive tract
     1. Structure and function of the ovary
         a. Meiosis (=oogenesis) results in one viable gamete (ovum)
  B. Menstrual Cycle
     1. Development of the follicle and ovum (Follicular phase: Days 0-14)
          a. Theca and granulosa cells            
     2. Corpus luteum maintains endometrium (Luteal phase: Days 14-28)
    3. Hormonal control of the menstrual cycle
          a. Follicular phase: Roles of GnRH, FSH, and Estrogen (E)
          b. Ovulation: E and the LH surge
          c. Luteal phase: Roles of E and Progesterone (P)
          d. If fertilization does not occur, corpus luteum degenerates  
     4. Simulation of this process
  C.  Fertilization of the egg
     1. Sperm action at the egg 
          a. Role of the acrosome
          b. Low sperm count and infertility.  Why is sperm count important?

V.  IMPLANTATION AND PLACENTA FORMATION  

  A. Early Development 
     1. Cleavage (Animation)
      2. Implantation (Animation)
         a. Blastocyst: Inner cell mass and trophoblast
  B. Placenta
     1. Formation of the placenta from fetal and maternal tissues
     2. Functions of the placenta
          a. Fetal nutrition
          b. Other functions
  C. Ectopic pregnancy: Implantation outside of the uterus
  D.  Regulation by placental hormones
     1. Early role of Human Chorionic Gonadotropin (hCG) 
          a. Pregnancy tests 
     2. Progesterone
     3. Estrogen 
     4. Chorionic Somatomammotropin 
     5. Parathyroid Hormone Related Peptide
     6. Relaxin
     7. Corticotropin Releasing Hormone (influences parturition, etc.) 
  E. Unique aspects of fetal physiology
     1. Fetal circulation (Animation)
          a. Foramen ovale and ductus arteriosus
     2. Fetal hemoglobin
          a. This is a unique Hb
          b. Oxygen dissociation curve for fetal Hb

VI.  PARTURITION AND LACTATION

  A. The process of parturition (child birth)
     1. Inherent smooth muscle rhythmicity sensitive to stretch
  B.  Neuroendocrine control by Oxytocin
     1. Positive feedback loop to hypothalamus encourages parturition
     2. Oxytocin blocks progesterone action
  C. Birth
  D. Following Birth
  E. Lactation: Production of milk.
     1. Before birth
          a. E, P, and Prolactin (PRL) effects on mammary gland development
          b. P inhibits PRL
     2. Following birth: Stimulation of milk secretion and ejection
          a. Prolactin promotes milk secretion
          b. Oxytocin stimulates milk ejection
              1) A neural reflex causes milk ejection
  F. Premature births
     1. Definition
     2. Incidence
     3. Risk factors associated with preterm births
          a. Chromosomal abnormalities, multiple pregnancies (twins), short
              cervix, high blood pressure, periodontal disease, smoking, high fat 
              diet/weight, age of mother, socioeconomic conditions, etc. 
     4. Possible complications posed by preterm birth
     5. Preventive treatment for preterm births

VIII.  CONTRACEPTION, ETC.

  A. Contraceptive methods: How effective are they?
  B. Oral Contraceptives
     1. How they work
     2. Side effects of the pill (if time permits)
  C. Terminating pregnancy
     1. RU-486 (mifepristone)
          a. Acts as a Progesterone receptor antagonist
		  
VIII. FILM: LIFE'S GREATEST MIRACLE (Voluntary attendance)