Reproduction & Development

Reprise: What is LIFE?

A. Modes of reproduction

  1. Asexual reproduction - lower invertebrates
  2. Hermaphroditism - e.g. earthworms, sponges
  3. Sequential hermaphroditism - some fish
  4. External fertilization
  5. Internal fertilization
  6. Development of embryo

B. Male reproductive system

External genitalia

  1. Penis
    1. Urethra
    2. Erectile tissue
  2. Scrotum

Internal genitalia

  1. Testes
    1. Seminiferous tubules: Spermatogenesis
      • Spermatocytes go thru meiosis I
      • Spermatids go thru meiosis II
      • Sperm cells mature: flagella, acrosome
    2. Leydig cells
      • Testosterone production
  2. Epididymis
  3. Vas deferens
  4. Seminal vesicles
  5. Prostate gland
  6. Bulbourethral gland

C. Female reproductive system

External genitalia

  1. Labia majora & minora
  2. Clitoris

Internal genitalia

  1. Vagina
  2. Uterus
  3. Oviducts (Fallopian tubes)
  4. Ovaries: oogenesis
    1. Oocytes (stuck in prophase I of meiosis)
      • surrounded by a follicle
    2. Follicles (400,000 are left at puberty)
      • stimulated to grow by FSH
      • only one follicle matures per month (Graafian follicle)
    3. Corpus luteum
      • LH causes ovulation
      • Remaining cells of follicle become corpus luteum

D. The female reproductive cycle

  1. The ovarian cycle
    1. Follicular phase: FSH stimulates growth of follicle
    2. Ovulation: LH surge causes rupture of follicle
    3. Luteal phase: LH causes corpus luteum to secrete Estrogen + Progesterone
  2. The menstrual cycle
    1. Menstrual phase: Lack of E+P = uterine lining shed
    2. Proliferative phase: Rise in Estrogen causes growth of uterine lining
    3. Secretory phase: Rise in Progesterone causes thickening/secretion of lining

E. Pregnancy

  1. Fertilization
  2. Implantation
  3. Embryonic growth

F. Human Development

Mother & fetus are 2 genetically distinct individuals, creating the possibility of immune system reactions. For example, erythroblastosis fetalis (Rh factor incompatibility) can be a problem.
  1. Labor 
    1. Oxytocin & prostaglandins

Application topics

  1. STDs
  2. Contraception
  3. In vitro fertilization
  4. Infertility

 

Other resources

http://www.allaboutmoms.com/usgallery.htm