1. The Reproductive System

2. Similarities and differences between males and females, but same goal: new life
Primary sex organs: gonads
Testes in males
Ovaries in females
These produce the gametes (sex cells)
Sperm in males
Ovum (egg) in females
Endocrine function also: secretion of hormones
Accessory sex organs
Internal glands and ducts
External genitalia

3. Male reproductive system
Testes (singular testis) or testicles: the gonads
In embryo, first develop in posterior abdominal wall, then migrate
Internal body temp too hot for viable sperm
Temp cooler in the scrotum because of superficial position

4. Spermatogenesis: sperm formation in the testes
Cross section of seminiferous tubule
Begins at puberty
400 million sperm/day
For baby not to end up with twice as many chromosomes as the parents, the sperm (as well as the egg) needs to have only half (1n) the # of chromosomes (1 of each of the 23)
(2n means 2 of each chromosome, one from each parent, totaling 23 pairs = 46 chromosomes)
Three stages:
Formation of spermatocytes
Meiosis
Spermiogenesis

5. Sperm can swim only after they have left the testis
Process of spermatogenesis is controlled by two hormones
FSH (follicle stimulating hormones) from anterior pituitary
Testosterone
primary male hormone
produces by testes *

6. Sperm are ejaculated from the epididymus
Not directly from the testes
Vas deferens* (or ductus deferens) 45cm (18”)
Stores and transports sperm during ejaculation
Runs superiorly from scrotum within spermatic cord, through inguinal canal and enters pelvis *

7. The Prostate Size & shape of a chestnut Encircles 1st part of urethra
Contribute to semen (milky fluid and enzymes)
PSA measured as indicator of prostate cancer (“prostate specific antigen”)
Prevents urine and sperm from travelling at the same time!

8. The Female Reproductive System
Production of gametes (ova, or eggs)
Preparation for support of developing embryo during pregnancy
Cyclic changes: menstrual cycle
Averages 28 days
Complex interplay between hormones and organs: at level of brain, ovaries and uterus

9. Gonads: the ovaries
Paired, almond-shaped, flanking the uterus in lateral wall of true pelvis
3 x 1.5 x 1 cm in size
Posterior view

10. Anterior view

11. Structure of ovary
Outer cortex houses developing gametes the oocytes, within follicles

12. The Ovarian Cycle Follicular phase 1st approx 14 days but variable
Egg develops in a follicle
Stimulated by follicle stimulating hormone
Estrogen produced
Ovulation
Egg released from follicle (leutinizing hormone surge)
Egg in abdominal cavity
Picked up by fallopian tube
Luteal phase
Post-ovulatory phase 14 days
Produces progesterone as well as estrogen
Progesterone stimulates uterus to be ready for baby
If no pregnancy, corpus luteum degenerates and you have menstruation

13. Ovulation Signal for ovulation is Lutenizing hormone surge
Ovarian wall ruptures and egg released,

14. Oogenesis Generation of eggs
Look at the diagram
Notice how meiosis makes eggs
Notice how the egg develops in the ovary

15. Fallopian (uterine) tubes, AKA oviducts
Fimbriae (fingers) pick up egg
Beating cilia and muscular peristalsis propel egg to uterus
____Fallopian tubes__
Fimbriae *
Enlargement of mucosa layer showing ciliated columnar epithelium
Cross section through entire tube
PID

16. The Uterus (womb)
In pelvis anterior to rectum and posterosuperior to bladder
Hollow, thick-walled organ
Receives
Retains
Nourishes fertilized egg=embryo
Uterus is pear-shaped (before babies)

17. The Uterine Wall* Three basic layers
Perimetrium: outer serous membrane
Myometrium: middle muscle
Endometrium: inner mucosal lining *

18. Pituitary hormones * Ovarian hormones
Time: one cycle (approx 28 d.)
Pituitary hormones
FSH: follicle stimulating hormone
LH: luteinizing hormone
Ovarian hormones
Estrogen
Progesterone
ovulation *
Follicular phase
Luteal phase

19. (inhibin: inhibits pituitary secretion of FSH)

20. Mammary glands (breasts)
Modified sweat glands
Both sexes but function (normally) only in lactating female
Produce milk to nourish baby

21. Conception
After ejaculation into the vagina, sperm swim to meet an egg
Sperm live 5-7 days (need cervical mucus)
Eggs live about hours, so conception only occurs during this short window
Fertilization occurs in the fallopian tube
Fertilization occurs at the moment the chromosomes from the male and female gametes unite

22. Initial days Cleavage (cell division)
Blastocyst stage by day 4: now in uterus

23. Implantation 6-9 days post conception - burrows into endometrium
Blastocyst floats for 2 days: “hatches” by digesting zona enough to squeeze out
6-9 days post conception - burrows into endometrium

24. The “Placental Barrier”
Sugars, fats and oxygen diffuse from mother’s blood to fetus
Urea and CO2 diffuse from fetus to mother
Maternal antibodies actively transported across placenta
Some resistance to disease (passive immunity)
Most bacteria are blocked
Many viruses can pass including rubella, chickenpox, mono, sometimes HIV
Many drugs and toxins pass including alcohol, heroin, mercury
Placental secretion of hormones
Progesterone and HCG (human chorionic gonadotropin, the hormone tested for pregnancy): maintain the uterus
Estrogens and CRH (corticotropin releasing hormone): promote labor