reproductive system

• spermatogenesis: sperm cell production
• spermatogonia: undifferentiated spermatogenic cell

  1. diploid germ cell (46 chromosomes)
  2. divide by mitosis to create spermatocyte
  3. the spermatocyte differentiates and divides by meiosis
  4. creates 4 haploid sperm cells (23 chromosomes)
• sperm

  1. oval head, haploid nucleus, acrosome: contains enzymes
  2. mid piece, cylindrical shape, mitochondria for energy
  3. tail, flagellum made of microtubule
• seminiferous tubules

  1. spermatogenic cells
  2. interstitial cells: leydig cells - produce testosterone
• epididymis: passage between seminiferous tubules and vas deferens
• vas deferens: ductus deferens

  • passage for sperm towards ejaculatory duct
• seminal vesicle: glandular tissue located near the base of the bladder

  • secretes a slight alkaline fluid (neutralize pH of vagina)
  • fructose to nourish sperm cells
  • prostaglandins to stimulate muscular contractions in uterus to aid sperm movement
  • empties into ejaculatory duct
• prostate gland

  • located below bladder and surrounds proximal part of urethra
  • secretes thin milky fluid, citrate to nourish sperm

  prostate specific antigen (PSA): enzyme that helps liquify semen so sperm can stay mobile
• bulbourethral gland (cowper's gland)

  • located below prostate gland
  • secretes lubricating fluid in response to sexual stimulation
• semen

  • fluid that is ejaculated, sperm cells, secretions from SV, PG, BG
  • average vol: 2-5ml
  • average 120 million sperm cells per ml
• scrotum: pouch of skin that surrounds the testes

  • testes hang outside body to remain 3 degrees celsius below body temp
  • higher temp affect spermatogenesis and sperm survival
• Penis: cylindrical organ that conveys urine and semen through the urethra

  body: shaft - contains erectile tissue, becomes stiff when filled w blood

  glans: cone on distal end
• prepuce: foreskin, loose fold of skin covering glans

  circumcision: surgical procedure that removes prepuce

  • associated w/ reduced risk of HIV, HPV, UTI
• Ovaries

  medulla: inner layer, loose connective tissue + blood vessels

  cortex: outer layer, ovarian follicles
• primordial follicles

  1. primary oocyte: single large cell
  2. follicular cells: epithelial cells surrounding primary oocyte, supplies nutrients to oocyte
  3. undergo meiosis early, process halts (as a fetus)
  4. no new primordial follicles form
• Primordial follicles

  1. 1 million remain at birth
  2. 400,000 remain at puberty
  3. 400-500 oocytes released throughout reproductive life
• oogenesis: egg formation

  1. primary oocyte resumes meiosis beginning at puberty
  2. meiosis is uneven, cytoplasm distributed unequally
• during meiosis I the secondary oocyte gets all the cytosol

  • secondary oocyte
  • first polar body
• during meiosis II the ovum gets all the cytosol

  • happens at fertilization
  • ovum (egg) is fertilized becoming a zygote
  • second polar body
• polar bodies give up cytosol and organelles to create massive egg, early rounds of cell division
• Ovulation

  • zone pellucida: layer of glycoprotein surrounding oocyte
  • corona radiata: layers of follicular cells surrounding oocyte
• new follicle is ready for ovulation every 28 days
• uterine tube: fallopian tube, oviduct
• infundibulum: funnel shape of uterine tube that encloses each ovary
• fimbriae: fringe of infundibulum
• uterine tube is lined w/ simple ciliated columnar epithelium to sweep oocyte toward uterus

  fertilization occurs in uterine tubes
• uterus

  • receives and sustains developing embryo
  • fundus: domed-shape top of uterus
  • body: top 2/3
  • cervix: bottom 1/3, extends toward vagina
• uterine wall

  • endometrium: inner layer
  • myometrium: smooth muscle layer
  • perimetrium: outer layer
• vagina

  • extends from uterus to outside
  • hymem: thin membrane of connective tissue and stratified squamous epithelium that partially covers vaginal orifive
• vulva: external structures that surrounds openings for urethra and vagina
• labia majora: rounded folds of adipose tissue and thin layer of smooth muscle

  • mons pubis: labia majora merge at anterior end of pubic region
• labia minora: flattened, longitudinal folds between labia majora

  • pink appearance due to blood vessels
• clitoris: small projection at anterior end of vulva

  • has columns of erectile tissue
  • has glans w/ sensory nerve fibers
• vestibule: space in-between labia minor

  • urethra opening at midline
  • vaginal opening in posterior position

  vestibular glands: secrete lubricating fluid in response to sexual stimulation (bartholin's gland)