The Testicles

1. The Testicles The Greatest Organ Known to Man

2. Function The testicles have two primary functions: • The production of testosterone • Production of sperm cells The testes secrete hormones such as testosterone and that is why they are an endocrinal gland

3. Testosterone • Testosterone secretion is regulated by a negative feedback system that involves releasing hormones from the hypothalamus and gonadotropins from the pituitary. • Testosterone is the male sex hormone. Testosterone will cause a boy to change into a man during puberty: he will grow a beard, his voice will get a lower pitch, his penis will grow, he will be able to have erections and will develop feelings of lust. • Testosterone also inhibits LH production by the pituitary by deactivating the hypothalamus.

4. Testosterone Feedback System

5. Sperm Cells • The mature sperm cell (spermatozoa) is 0.05 millilitres long. It consists of a head, body and tail. The head is covered by the ac cap and contains a nucleus of dense genetic material from the 23 chromosomes. • It is attached from the neck to the body containing mitochondria that supply the energy for the sperm's activity. The tail is made of protein fibres that contract on alternative sides, giving a characteristic wavelike movement that drives the sperm through the seminal fluid, which also supplies additional energy. • Sperm swim at an average rate of about 3mm (0.12 inches) per minute. • Sperm cells are made in the testes where it takes about 72 days for one sperm to grow.

6. Sperm Cells Continued • Healthy Males make 200-300 million sperm cells every day. • Semen contains small amounts of more than thirty elements, including fructose, ascorbic acid, cholesterol, creatine, citric acid, lactic acid, nitrogen, vitamin B12, and various salts and enzymes. • All normal cells have 46 chromosomes but sperm have half that number or, 23. If and when the sperm joins ups with the female’s, egg (ovum) which also has 23 chromosomes, together they add up to 46 chromosomes. • The sperm make up only about 5% of what a man ejaculates each time he ejaculates and a single sperm is the smallest cell in the body.

8. Other Functions • The functions of the testicles are under control of the anterior pituitary gland which secretes luteinizing hormone and follicle-stimulating hormone. These are known as gonadotropic hormones.

9. LH • The release of luteinizing hormone is controlled by pulses of gonadotrophin-releasing hormone (GnRH) from the hypothalamus. It is responsible for the release of testosterone.

10. FSH • FSH regulates the development, growth, pubertal maturation, and reproductive processes of the human body. FSH and LH are partners in an atrospect. Like LH, the release of FSH is controlled by pulses of gonadotrophin-releasing hormone (GnRH) from the hypothalamus. FSH also acts directly on the sperm producing cells of the seminiferous tubules.

11. Anatomy • The epididymis is connected to the testicle and overlies it like a cap; it contains a very large amount of microscopically small tubes. From the epididymis, the vas deferens will conduct the freshly made sperm cells to the area of the prostate.

12. Anatomy Continued • The vas deferens runs together with blood vessels that supply blood to and from the testicle and some muscle fibers; as a sort of long thin sausage they perforate the abdominal wall at the groin. Since, from the standpoint of the abdomen, the testicles are located 'outside' the body, there must be a tiny hole in the abdominal wall there to let the vas deferens in. Right behind the prostate the vas deferens joins the outlets of the seminal vesicles to be able to leave the body through the urethra as semen, in search of a female egg cell.

14. Did You Know? • The testicles are round in shape and about the size of golf balls. The are equivalent to to ovaries in women and for the first six weeks of age the gonads (which later develop into sex organs) are the same for males and females.

15. Homeostasis • One homeostatic mechanism in the testicles is the reaction to temperature. There are a number of muscles that raise and lower the testes to maintain the optimum temperature. The main one is the cremasteric muscle.The cremasteric muscle shortens and pull the testicle closer toward the body, which provides more warmth when the outside temperature is cool. When testicle cooling is necessary, the cremasteric muscle relaxes and the testicle is lowered away from the warm body to cool.

16. Disorders • There are many disorders linked with the testicles, primarily STD’s. An example of one of these STD’s is gonorrhea. Gonorrhea is cause by a bacteria that can grow and multiply in practically all areas of the reproductive tract. Gonorrhea is a very common infectious disease. More than 700, 000 people in the U.S. get new gonorrhea infections each year.

17. Chlamydia • Chlamydia infection is caused by the bacteria bacterium Chlamydia Trachomatis. • Chlamydia infection is one of the most common sexually transmitted infections worldwide — about 2.8 million cases of chlamydia infection occur in the United States each year. It is the most common STD in the U.S. with gonorrhea being the second. • Chlamydia is known as a "silent" disease because about three quarters of infected women and about half of infected men have no symptoms • Some symptoms can include a burning sensation when urinating or in rare cases pain and swelling in the testicles. • Chlamydia can lead to such things as infertility and discharge of the penis

18. Male Reproductive Tract AbnormalitiesDid You Know? • Two common male reproductive tract abnormalities are cryptorchidism, where the testicles haven’t descended after age one, and hypospadias, a common abnormality of the penis that appears as an abnormal opening on the underside of the penis rather than at the end