Reproductive System 

Gonads: Primary Sex Organ 

  • Produce gametes, secrete hormones (testosterone, estrogen, progesterone) 

  • Gonads (males) Ovaries (females) 

  • Gametes: male – sperm/female – eggs


  • Mitosis:  body cells, growing cells by duplicating, 42 chromosomes 

Vs.

  •  Meiosis: sex cells(sperm, eggs), 23 chromosomes each – 42 when added together 


  • Zygote  

  • Egg + Sperm = Zygote a Fertilized Egg 

  • We can call it a zygote from fertilization to implantation (when the zygote sticks to the wall of the uterus) 

  • Embryo – calling it an embryo from implantation up to 8 weeks 

  • Fetus – after 8 weeks  

  • It takes 7 days to go from the fallopian tube to the uterus 

  • Implanted into the endometrium 

  • Releases a hormone that is now in the blood, urine, and stops the endometrium from shedding = HCG – Human Chorionic Gonadotropin


Male: 

Testes: 

  • Located: External Pouch (Scrotum)

  • Function: Produce sperm and testosterone  


  • Seminiferous tubules: (outside of the pelvic cavity) 

    • Tightly coiled structures inside the testes that produce sperm 


  • Epididymis: (outside of the pelvic cavity) 

    • Where sperm mature 


  • Vas Deferens: (inside of the pelvic cavity) 

    • Connects the testes to the urethra 


  • Urethra: (inside of the pelvic cavity)

    • Connects the urinary bladder to the exterior of the body 


  • The prostate gland and the seminal vesicles both secrete seminal fluid (inside the pelvic cavity)








Female - all in the pelvic cavity 


Ovaries:

  • Located on either side of the uterus in the pelvic cavity 

  • Function: produce and release eggs (ova), produce estrogen and progesterone 

    • (When estrogen decreases, bone density decreases, and cholesterol levels can rise) 

    • Inside the ovaries are immature egg cells (oocytes), each one surrounded by a follicle

    • When one becomes mature, the ovum leaves the ovary and enters the fallopian tube 

    • The ovaries release an egg and send it into the fallopian tube, aka ovulation 


  • Fallopian tube 

    • Connects the ovaries to the uterus

    • site when fertilization occurs 

    • If sperm is present in the fallopian tube, fertilization occurs 


  • Fertilization 

    • Joining of the nuclei of the egg and sperm 


  • Uterus

    • Hollow organ located between the urinary bladder and the rectum 

    • Smooth muscle contracts to push the baby out 


  • Endometrium 

    • The tissue that lines the uterus 


NOTES: 

  • Eggs are “usable” for 12-24 hours, sperm is “usable” for 12-48 hours

  • The reproductive system is posterior to the digestive system 



Menstrual Cycle 

  • The beginning of a cycle is the first day of the period 


4 Hormones 

  • Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are responsible for triggering ovulation 

  • Progesterone (P) and estrogen (E) are responsible for building the lining of the uterus 


Stages: 

  • Menstrual phase: 

    • 3-7 

    • Endometrium detaches and exits the body (including the unfertilized egg) 

    • All 4 hormones are at their lowest 


  • Follicular phase 

    • About 10 days, right after the menstrual phase 

    • FSH and LH increase to cause the follicle to mature in the ovary 

    • E levels begin to rise, causing the lining to grow in preparation to receive an egg


  • Ovulation: 

    • Middle through cycle (day 14) 

    • Follicle ruptures and releases a mature egg 

    • FSH and LH are at their highest and decrease after this 

    • If FSH and LH don't increase, then there is no release of an egg 

    • FSH and LH are low when pregnant 


  • Luteal phase 

    • 7-12 days 

    • E and P increase 

    • Uterine lining continues to grow 

    • If E and P don't increase, the lining does not grow 

    • If fertilization occurs, the lining does not shed, and P and E stay increased 

    • P and E are antagonists to FSH and LH, one is up, the other is down