1. Male Reproductive System

2. Scrotum Purpose: - encase / protect the testes
- regulate temperature of testes
*sperm production is ideal about 2 degrees cooler than body temp.
Body temp rises = scrotum descends
Body temp decreases, scrotum pulls testes closer into body

3. Penis Glans – head of penis Corona – ridge/ where head and shaft meet
Corpora Cavernosa – two spongy bodies of erectile tissue on either side of the penis which become engorged with blood from arteries in the penis, thus causing erection.
Urethra – exiting path for semen
Meatus - external opening of the urethra

4. STOP Turn to a partner and discuss the following:
1 - Discuss a situation in which triggers the scrotum to ascend and/or descend. Discuss WHY this happens.
2 – Discuss how the corpora cavernosa plays an importance in the reproductive process.
**Be prepared to discuss

5. Testes male gonads (primary sex organs)
~1 and 1/2” long; ~ 1” wide (plum)

6. Testes Inside Testes… 1. Seminiferous tubules - forms sperm
2. Interstitial cells
- In tissue surrounding seminiferous tubules
- produce testosterone

7. Epididymis Duct system - 20’ inches long; - 20 days for sperm to
travel through
- Temporary storage for immature sperm
- Sperm mature as they travel through
- When stimulated the walls of epididymis contract and expel sperm into the vas deferens

8. Vas Deferens
a.k.a - ductus deferens
-Propels sperm using peristaltic contractions from epididymis to the ejaculatory duct

9. Urethra -final part of the duct system -base of the bladder
-Internal urethral sphincter contracts during ejaculation to prevent urine from entering & sperm from going into bladder

10. STOP
With a different shoulder partner, create an analogy for the functions of the following:
Testes
Epididymus
Vas Deferens
Urethra
**Be prepared to discuss

11. Seminal Vesicles (accessory)
Location:
-base of bladder
-merges with vas deferens to form ejaculatory duct so sperm & seminal fluid enter at same time.

12. Seminal Vesicles (accessory)
-Rich in fructose = “sperm food”
-Vitamin C
-prostaglandins = stimulate female uterine contraction to help sperm up move up into the uterus

13. Prostate (accessory) Location: Upper part of urethra Purpose:
-Secretes alkaline fluid to neutralize semen
- acidity left over from urine
- help protect sperm in the acidic environment of the vagina
-During ejaculation the fluid enters the urethra mixing with the seminal fluid

14. Bulbourethral Gland (accessory)
Location:
-inferior to prostate
-empty directly into
urethra
Purpose:
-Produce thick mucous that passes first through urethra during ejaculation
a.k.a. “pre-ejaculatory fluid”
-Cleans urethra and lubricates urethra

15. STOP
With a DIFFERENT partner than the first 2 times, discuss the following:
Come up with a general statement that summarizes what the prostate, seminal vesicles, and bulbourethral gland do for the sperm.
Decide on 1-2 key terms that you can associate with each of the 3 accessory glands.

16. Semen -White, sticky fluid
-The final mix containing sperm and accessory fluids
Testes/Epididymis – produces about 5%
Seminal vesicles - produce 60%
Prostate - produces 30%
Bulbourethral gland – produces 5%
Benefit of so much fluid?  dilutes sperm = increases mobility
~ 2- mL /ejaculation
~ million sperm / ejaculation

17. In summary… The journey of the sperm
1 – Seminiferous tubules (inside testicle)
2 – Epididymis
3 – Vas Deferens
4 – Urethra
Structures that add to sperm on it’s journey
1 – Seminal vesicles
2 – Prostate gland
3 – Bulbourethral gland

18. Let’s recap  Match the following structure to its function
____ Scrotum
____ Testes
____ Epididymus
____ Vas deferens
____ Seminal vesicle
____ Prostate gland
____ Bulbourethral
gland
Adds nourishment to sperm
Sperm matures here for 20 days
Sperm are created here
Regulate temperature of testes
Lowers the acidity of seminal fluid
Clears urethra prior to ejaculation
Carries sperm to urethra

19. Skit Time!!
#1 – Seminiferous
Tubules
#2 – Epididymus
#3 – Vas Deferens
#4 – Prostate Gland
#5 – Seminal Vesicles
#6 – Bulbourethral
Gland
#7 – Urethra
#8 – Scrotum
GOAL: Create a mini-skit that portrays the function of the gland or structure assigned.
RULES:
No written words
No pictures
Act/talk out the function

20. II. Male Physiology
Pituitary Gland secretes TWO hormones involved in sperm production
LH – Leutenizing hormone
FSH – Follicle-stimulating hormone

21. Luteinizing Hormone (LH)
a. released during and after
puberty
b. stimulates interstitial cells
in testes to produce testosterone.

22. Follicle Stimulating Hormone (FSH)
a. released during and after puberty
b. stimulates maturation of seminiferous tubules
c. stimulates spermatogenesis

23. Testosterone
a. released by:
interstitial cells
b. produces sperm
c. causes secondary sex characteristics
i. deepen voice
ii. Hair growth
iii. Increased muscle mass & bone density
What do you think are secondary sex characteristics? Examples?

24. 4. Negative Feedback Control
This schematic shows how a man’s hormones and organs work together to regulate sperm production. Positive feedback relationships are indicated with a plus sign; negative feedback relationships with a minus sign.
The hypothalamus is part of the brain. It produces gonadotropin releasing hormone (GnRH) in pulses, from once a day to once an hour. GnRH triggers the release of 2 hormones from the pituitary gland: luteinizing hormone (LH) and follicle stimulating hormone (FSH). LH and FSH act on different types of cells within the testes. LH induces the Leydig cells surrounding the seminiferous tubules to secrete testosterone (T). FSH, along with the T from the Leydig cells, induces the Sertoli cells lining the seminiferous tubules to make both inhibin B and immature sperm, or spermatids.
Inhibin B acts on the pituitary gland in a negative feedback loop. When enough inhibin is present, the pituitary stops producing FSH. T gives negative feedback to both the pituitary and the hypothalamus, decreasing the production of GnRH and LH directly.
The immature sperm travel through the seminiferous tubules to the epididymis. In the epididymis, the spermatids are converted to mature sperm. The process takes about 2.5 months to complete. Only once the sperm are mature do they pass into the vasa deferentia.
Male hormonal contraceptives work by attempting to block the production of sperm. Depending on the formulation, the MHC stops the secretion of one or more of the hormones and feedback loops in the diagram.

25. B. Spermatogenesis
1. Begins during puberty; continues throughout life
2. Millions of sperm made daily
3. Birth to puberty:
a. spermatogonia (primitive stem cell)
divide (mitosis) to create more stem cells

26. 4. during & after puberty (increase in FSH)
a. when spermatogonium divides
one stem cell & 2 daughter cells.
b. one daughter cell maintains stem cell population
c. other daughter cell continues through meiosis

27. 5. Spermiogenesis
1. last stage of spermatogenesis
2. spermatids loose cytoplasm, etc
3. develop tail