Reproductive Physio

• Reproductive Physiology


  The study of the biological functions and processes related to reproduction in living organisms
• Sperm path

  • Seminiferous tubule
  • Epididymis
  • Vas deferens
  • Ejaculatory duct
  • Urethra
  • Penis

  
• Male reproductive anatomy

  • Seminiferous tubules are in the testes
  • Penis
  • Accessory glands that produce seminal fluid: Seminal vesicles, Prostate, Bulbourethral glands

  
• Semen

  Sperm + seminal fluid
• Benign Prostate Hyperplasia (BPH)

  Cells within the prostate gland proliferate, making it larger
• Up to 90% of men >80 will experience BPH
• Symptoms of BPH

  Difficulty initiating urination, slow urine flow, feeling like urine stays in the bladder
• Testis anatomy

  • Sperm are produced in the seminiferous tubules
  • Sperm mature in the epididymis
  • Sperm leave via efferent ductules before entering the Vas Deferens

  
• Intracytoplasmic sperm injection


  A technique used for male infertility
• Testis histology

  • Intratubular compartment: Sertoli cells, Spermatogonia, Spermatocytes, Spermatozoa
  • Peritubular compartment: Leydig cells, Blood vessels

  
• Sperm development


  Within the testes

  
• Leydig cells


  • Respond to LH, Secrete Testosterone, Testosterone preferentially inhibits LH
• Sertoli cells


  • Respond to FSH, Secrete inhibin and Androgen Binding Protein (ABP), Inhibin inhibits FSH
• Hypothalamic/Pituitary/Testis Axis

  1. GnRH from Hypothalamus stimulates LH and FSH release from Anterior Pituitary

  2. LH stimulates Leydig cells to secrete Androgens

  3. FSH stimulates Sertoli cells to secrete Inhibin and Androgen-Binding Protein
• Erectile reflex


  Physiological process that leads to an erection

  
• Erection mechanism

  1. Corpus cavernosa accommodates arterial blood

  2. Flaccid = no blood to cavernous spaces, Erect = increased blood flow into cavernous spaces

  3. Increased arterial blood flow compresses veins, Blood can't leave via veins and is "trapped" in the penis

  
• Cellular mechanism for erection

  • Sexual stimulation causes release of NO from cavernous nerves
  • NO activates Guanylyl cyclase (GC)
  • GC converts GTP to cGMP
  • cGMP causes relaxation of arterial smooth muscle, promoting vasodilation and blood flow into the penis

  
• Viagra


  A medication that works by inhibiting the enzyme that breaks down cGMP, thereby prolonging the erection
• Female reproductive anatomy

  • Fallopian tube, Ovary, Uterus, Cervix, Vagina
• Pregnant women frequently use the restroom
• Ovarian histology

  • Ovary consists of an outer cortex and inner medulla
  • Follicles contain developing oocytes (immature eggs)
  • Corpus luteum forms after ovulation and supports pregnancy
• Follicular development and changes in the ovary

  1. Embryonic development generates primordial follicles

  2. Primary follicles are present at birth

  3. During puberty, primary follicles mature to secondary, tertiary, and dominant follicles

  4. At ovulation, the oocyte breaks out of the ovary and travels into the fallopian tubes

  5. The remaining ruptured follicle will be converted into the corpus luteum
• Follicular cell types

  • Theca cells are the outermost layer(s), have LH receptors and produce androgens
  • Granulosa cells are closest to the ovum, have FSH receptors and produce estrogens
• Hypothalamic/Pituitary/Gonadal Axis

  Hypothalamus releases GnRH, Anterior Pituitary releases LH and FSH, Gonads (testes/ovaries) produce Testosterone, Estrogen, Progesterone
• Androgen actions


  Promote development of male secondary sexual characteristics
• Estrogen actions


  Promote development of female secondary sexual characteristics, regulate menstrual cycle
• Progesterone actions


  Prepare uterus for implantation, maintain pregnancy
• Leydig cells produce androgens, Granulosa cells produce estrogens
• Hypothalamic/Pituitary/Gonadal axis in individuals with testes vs ovaries


  Differences in the cell types and hormones involved
• The Menstrual Cycle


  Anterior Pituitary Hormones, Changes in the ovary, Hormones released by the ovary, Changes in the uterus

  
• Stages of the menstrual cycle

  Follicular phase, Ovulation, Luteal phase

  
• Menstrual cycle


  1. Occurs monthly in non-pregnant women

  2. Stops when a woman gets pregnant
• Uterine cycle

  1. Menses

  2. Proliferative

  3. Secretory

  
• Menses


  Uterine lining is shed
• Proliferative


  Uterine lining builds up
• Secretory


  Uterine lining prepares for implantation
• Purpose of uterine cycle phases

  Prepare the uterus for implantation
• Follicular phase


  Coincides with proliferative and secretory phases of uterine cycle

  
• Luteal phase


  Coincides with secretory phase of uterine cycle
• Hormone concentrations during menses


  Anterior pituitary and ovary