1. General Anatomy of the Male Reproductive System

2. Adolescence Puberty Burst of hormones activate maturation of the gonads: testes Begins: 9 – 14 yrs of age Abnormally early = precocious puberty Delayed = eunuchoidism

3. General Physical Changes Enlargement of the external and internal genitalia Voice changes Hair growth Mental changes Changes in body conformation and skin Sebaceous gland secretions thicken/increase  acne

4. External Genitalia Gonads = testes undescended by birth= cryptorchidsim Scrotum Penis

5. scrotum consists of skin and subcutaneous tissue A vertical septum, of subcutaneous tissue in the center divides it into two parts, each containing one testis. Smooth muscle fibers, called the dartos muscle, in the subcutaneous tissue contract to give the scrotum its wrinkled appearance. When these fibers are relaxed, the scrotum is smooth. the cremaster muscle, consists of skeletal muscle fibers and controls the position of the scrotum and testes. When it is cold or a man is sexually aroused, this muscle contracts to pull the testes closer to the body for warmth.

7. General Anatomy of the Male Reproductive System

8. Anatomy of the Male Reproductive System

9. Internal and external anatomy of the Testis Pathway for Sperm 1. Seminiferous tubule 2. Straight tubule 3. Rete testis 4. Efferent duct 5. Ductus Epididymis 6. Ductus deferens

10. Testes Each testis is an oval structure about 5 cm long and 3 cm in diameter Covered by: tunica albuginea Located in the scrotum There are about 250 lobules in each testis. Each contains 1 to 4 -seminiferous tubules that converge to form a single straight tubule, which leads into the rete testis. Short efferent ducts exit the testes. Interstitial cells (cells of Leydig), which produce male sex hormones, are located between the seminiferous tubules within a lobule.

12. Histology of the Testis and Spermatogenesis

13. Steps of Spermatogenesis Spermatids: Cells resulting from meiosis II, become spermatozoa

16. Epididymis a long tube (about 6 meters) located along the superior and posterior margins of the testes. Sperm that leave the testes are immature and incapable of fertilizing ova. They complete their maturation process and become fertile as they move through the epididymis. Mature sperm are stored in the lower portion, or tail, of the epididymis

17. spermatic cord contains the proximal ductus deferens, testicular artery and veins, lymph vessels, testicular nerve, cremaster muscle and a connective tissue covering.

18. Duct System Sperm cells pass through a series of ducts to reach the outside of the body. After they leave the testes, the sperm passes through the epididymis, ductus deferens, ejaculatory duct, and urethra.

19. Ductus Deferens [vas deferens] a fibromuscular tube that is continuous with the epididymis. enters the abdominopelvic cavity through the inguinal canal and passes along the lateral pelvic wall, behind bladder & toward the prostate gland. Just before it reaches the prostate gland, each ductus deferens enlarges to form an ampulla. Sperm are stored in the proximal portion of the ductus deferens, near the epididymis

20. Ejaculatory Duct Each ductus deferens, at the ampulla, joins the duct from the adjacent seminal vesicle (one of the accessory glands) to form a short ejaculatory duct.ampulla Each ejaculatory duct passes through the prostate gland and empties into the urethra.

21. Organs involved in the Production of Semen Seminal Fluid: Volume of a typical ejaculation is 2.5 –5.0ml with a sperm count of 50 –150 million sperm (under 20 million sperm is considered infertile), fluid is slightly alkaline at pH 7.2 –7.7. Seminal Vesicles: Produce 60% of the volume of seminal fluid; SV’s produce an alkaline viscous fluid that contains: fructose, prostaglandins, and clotting proteins

22. Organs involved in the Production of Semen Prostate Gland: Produce 25% of the volume of seminal fluid; This fluid is a milky, slightly acidic fluid that contains citric acid (for ATP production), acid phosphatase along with several other enzymes ( prostate-specific antigen PSA, pepsinogen, and lysozyme Bulbo-urethral gland: produces alkaline mucus that help lubricate the urethra and the head of the penis Ampulla of ductus deferens : releases up to 150 million sperm cells

23. The Male Sexual Response Arousal: various erotic thoughts and physical stimulation triggers parasympathetic reflexes that cause an erection. Erection: occurs when neurons release Nitric oxide at their synaptic endings. NO causes smooth muscles of the penile arteries to relax, vessels dilate, blood flow to the erectile tissue increases. The vascular channels engorge with blood, resulting pressure causes the penis to become stiff.

24. The Male Sexual Response During arousal increases in heart rate, blood pressure, skeletal muscle tone, and hyperventilation occur Bulbourethral glands: continued stimulation causes the release of mucus from these glands, this mucus lubricates the penile urethra and the glans penis. These secretions can carry sperm.

25. The Male Sexual Response Plateau stage: Changes that begin during arousal are sustained at an intense level, head of the penis increases in diameter and the testes swell due to vasocongestion. Toward the end of the plateau stage, emission occurs. Emission: sympathetic stimulation causes peristaltic contractions of the ampulla that push fluid and spermatozoa into the ejaculatory duct, peristaltic contractions of the seminal vesicles and the prostate push seminal fluid in the ejaculatory duct and the penile urethra. Contraction of the internal urethral sphincter and the bladder occurs.

26. The Male Sexual Response Ejaculation: Sympathetic stimulation of the ischiocavernosus and bulbospongiosus muscles causes powerful rhythmic contractions that push the semen out of the penile urethra. Orgasm; intensely pleasurable sensations associated with ejaculation. Other physiological changes include pronounced increase in heart rate and blood pressure.

27. The Male Sexual Response Resolution: Sense of profound relaxation- genital tissues, heart rate, blood pressure, breathing, and muscle tone return to normal. During early period of resolution, males enter a refractory period during which a second ejaculation and orgasm are physiologically impossible.

28. Erection Involves increase in length, width & firmness Changes in blood supply: arterioles dilate, veins constrict The spongy erectile tissue fills with blood Erectile Dysfunction [ED] also known as impotence

29. Hormones  Follicle-stimulating hormone (FSH) stimulates spermatogenesis Interstitial Cell Stimulating Hormone (ICSH) stimulates the production of testosterone testosterone testosterone stimulates the development of male secondary sex characteristics & spermatogenesis.