Biology Seminar  Testosterone

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.

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.

Functions of Testosterone

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

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. 

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.

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

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

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.

Testosterone in Females

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

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

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

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

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)

Questions

What is Testosterone?

What happens to testosterone levels with age?

What are 3 emotional changes men with low testosterone encounter?

Can testosterone be found in vertebrates?

The End! Testosterone in women - Youtube