1. Reproductive System & Human Development

2. Male Reproductive System
What do you already know?

3. Male Reproductive System

4. Male reproductive system functions
Testes –
Produce sperm in a process called spermatogenesis
Produce testosterone
Sperm are produced from puberty until the end of life, but fertility and sperm quality do decline with age.
Schizophrenia, autism, preterm birth and certain birth defects increase in dads over 35.
Testosterone
Causes development of reproductive organs and secondary sexual characteristics (increased hair growth, thickening of bones, deepening of bones, and enlargement of muscles)
Responsible for sex drive
Supports sperm formation

5. Male reproductive system functions
epididymis –
Storage and final site of maturation for sperm
Contracts during ejaculation to push sperm into ductus deferens
Ductus deferens carries
sperm to ejaculatory duct.
The ejaculatory duct then
joins the urethra.
Fun fact: Vasectomy involves severing the ductus deferens (aka vas deferens) so that sperm cannot be carried to the urethra, rendering a man infertile.

6. Accessory glands & semen
The accessory glands (seminal vesicles, prostate, and bulbourethal gland) produce most of the fluid that makes up semen.
Seminal vesicles – produce fluid that nourishes and activates sperm
Prostate – produces fluid that activates sperm
Bulbourethal gland – produces fluid before ejaculation that reduces acidity of urethra and acts as lubricant for sexual intercourse
Fun fact:
The prostate becomes enlarged in most men with age, making urination more difficult.
Prostate cancer second most common cancer in men (after skin), affecting 1 in 7 men.
Sperm activation – increase in motility
Bulbourethal gland secretion

7. External genitalia
The scrotum contains the testes and helps maintain optimal temperatures for sperm production by hanging loosely (at high temps) or wrinkling up (at low temps).
Erection occurs when the erectile tissue of the penis fills with blood, making the penis larger and rigid.
Fun fact:
Atherosclerosis is the #1 cause of ED
Sperm activation – increase in motility
Bulbourethal gland secretion

8. Female Reproductive System
What do you already know?
Sperm activation – increase in motility
Bulbourethal gland secretion

9. Female Reproductive System
Sperm activation – increase in motility
Bulbourethal gland secretion

10. Female Reproductive System Functions
Ovaries
Produce oocytes (eggs)
Produces estrogens
develop female sexual characteristics
Establish menstrual cycle and supports growth of endometrium
Produces progesterone
Establishes menstrual cycle
Supports pregnancy and milk production
Fun Fact: A woman is born with all the oocytes she will ever have, all paused at an early stage of development. Starting at puberty, several oocytes finish developing every month, with the ‘best’ of these rupturing through the ovary wall during ovulation
An ultrasound of an ovary showing 4(?) developing follicles

11. Female Reproductive System Functions
Uterine (Fallopian) tubes
Beating of cilia within tubes carries the egg from the ovary to the uterus
Not attached to ovary. Egg is pulled into uterine tubes by waving of fimbriae (hair-like projections of uterine tubes that partially surround ovary.
Normal site of fertilization.
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The egg is only viable for ~24 hours after ovulation, but it takes 3-4 days for it to reach the uterus.

12. Female Reproductive System Functions
Uterus
Receives & nourishes fertilized eggs to support pregnancy
Normally size of pear
Endometrium is inner lining. This builds up every month in order to allow implantation of fertilized egg, but sloughs off (menstruation) if zygote does not successfully implant and grow.
Myometrium is muscular wall.
Cervix is the opening; prevents premature birth. Opens fully to 10 cm diameter during earliest stages of labor.

13. Menstrual Cycle Day 0 is first day of menses
Normal cycle varies from days
No matter what cycle length, ovulation occurs ~14 days prior to menstruation
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14. Questions??

15. Pregnancy and Embryonic Development
NOVA show (~50 min)
Baby center short clips