1. Biology Seminar 
Testosterone

2. What is testosterone? 
Testosterone is a predominant male sex/steroid hormone.
It is produced by the male testes and the adrenal gland throughout the fetus' eighth week.
 It is a molecular messenger that travels through the blood stream to act on organs and tissues in a person's body. 
During the fetal and embryonic stages, testosterone promotes the production of male sex organs.

3. During pre-teen to teen years, testosterone has a great impact on on the growth of the testes, body hair, muscles, bones and the deepening of the voice and the enlargement of the male sex organs. 
Levels of testosterone rise rapidly during puberty.

5. Functions of Testosterone

6. Testosterone creates muscle cells and causes them to grow in size and strength.

7. The Brain and the Heart 
Testosterone has a great impact on mood, energy levels, sense of vitality and sexual drive of a person. 
This hormone also influences cardiovascular risk factors indirectly through its effect on the amount of fat in the body. 

8. Testosterone reduces body fat
Testosterone reduces body fat. Particularly in the midsection of the chest. 
Testosterone improves bone density and prevents bone destruction from aging; Thus reducing the risks of fractures.

9. Responsible for the normal growth and development of the male sex organs. 
To maintain other sex characteristics.
Produce sperm.

10. Feedback Cycle Low Testosterone levels in the blood
Intersitial cells stop producing testosterone
(Hypogonadism)
GnRH - Gonadotropin releasing hormone
Stimulates hypothalamus
LH- Luteinizing Hormone
Small amount of GnRH released
Secretes GnRH
FSH - Follicle Stimulating  Hormone
Stimulates anterior pitulitary to produce LH and FSH
Interior pituitary inhibited
Stimulation of the interstitial cells to produce more testosterone
Inhibits hypothalamus
Increase of testosterone levels in blood

11. Hypogonadism- The failure to produce or a decrease in the production of testosterone.
Causes: Genetics, illnesses, injuries or because of abnormal hormonal stimulation of the testes by other glands (eg. the pituitary gland).
Levels of testosterone slowly decline as men get older (mostly during ages 48 to 70). This is called "Viripause" also known as "men menopause".
-The testosterone receptors become less receptive while the amount of  testosterone decreases due to an increase in a blood protein that binds with the hormone. (30 to 40 percent).
This can lead to increase in body fat from the loss of muscle strength and function.

12. Testosterone in Females

13. Testosterone and estrogen
The ovaries produce both testosterone and estrogen. 
Small quantities of testosterone are released into the blood stream by the ovaries and adrenal glands

14. Estrogen - Created in the placenta. Produced during pregnancy
The primary sex hormone of childbearing women
formed from ovarian follicles
Responsible for female characteristics
Responsible for bone health
Contributes to gynecologic problems like cancer

15. Causes of failure levels of Estrogen
Pregnancy failures
Pre-menopause and menopause  
Extreme exercise or training
Eating disorders
Polycystic ovarian Syndrome (PCOS)
Decrease in levels of Estrogen can also decrease after childbirth

16. The ovaries are very much involved in the growth maintenance and repair of reproductive tissues. They also influence the body tissues and bone mass.

17. High levels of Testosterone in female
Women with high levels of testosterone can experience male hair patterns on the face and the chest
Some women may experience unusual hair growth while others become bald ( the ovarian and adrenal gland tumors raise testosterone levels)

18. Questions

19. What is Testosterone?

21. What happens to testosterone levels with age?

23. What are 3 emotional changes men with low testosterone encounter?

25. Can testosterone be found in vertebrates?

27. The End!
Testosterone in women - Youtube