1. No. 12
1. Introduction of the Genital System
2. Male Genital System

2. Chapter 5 The Genital System
The introduction of the genital system:
Functions: The organs of the male and female reproductive system ensure the continuance of the species. They do this by producing gametes, or germ cells, and by providing a method by which the gametes of the male (sperm) can be introduced into the body of the female, where one of them joins with a gamete (ovum) of the female.

3. Constitutions: The genital (or reproductive) system includes the male and the female genital organs. Both systems are composed of internal and external genital organs.
The internal genital organs consist of gonad, reproductive canals and accessory glands.
The external genital organs are mainly copulatory organs.

4. Table 1: The components of male and female reproductive systems
Divisions
Male genital organs
Female genital organs
Internal genital organs
Gonad
Testis
Ovum
Reproductive canals
Epididymis, Ductus deferens, Ejaculatory duct, Urethra
Uterine tube, Uterus, Vagina
Accessory glands
Seminal vesicle, Prostate, Bulbourethral gland
Greater vestibular gland (Bartholin gland)
External genital organs
Scrotum, Penis
Vulva (Female pudendum)

6. Section 1 The Male Genital Organs
Composition:
The male genital organs are composed of internal and external genital organs.
1. The internal male genital organs consist of:
Gonad—testes
Reproductive canals (epididymis, ductus deferens, ejaculatory duct, urethra)
Accessory glands (seminal vesicle, prostate gland, bulbourethral gland).

7. The testes produce sperms, which are stored in the epididymides
The testes produce sperms, which are stored in the epididymides. During ejaculation the sperms pass through the ductus deferens, ejaculatory ducts and urethra to be expelled from the body.
The accessory glands secrete the fluid to be added to the seminal fluid to maintain the nutrition and activity of the sperms.

8. 2. The external male genital organs are the scrotum and penis.
The penis is the copulatory organ by which the sperms are introduced into the female genital tract.
The scrotum houses the testes and epididymides.

9. Ⅰ. The Internal Genital Organs
Ⅰ) The Testes
The testes are male gonads, producing gametes of the male (sperms) and male hormones. They average 4-5 cm in length and weight g.

10. 1. The location of testes
The testes are paired oval-shaped organs, being housed in the scrotum.

12. 2. The features of testes
Each testis has the superior and inferior extremities, the lateral and medial surfaces, and the anterior and posterior borders.
The blood vessels, nerves and lymphatics pass through the posterior border to enter or leave the testis. The posterior border connect with the epididymis.

13. 3. The structure of testes
The testes are covered by a dense layer of fibrous membrane, the tunica albuginea. It is thicker on the posterior border of the testis and form the mediastinum testis, which gives off the septula testis extending inward to divide each testis into a series of compartments ( ) called lobules of testis.
Each lobule contains two to four tiny coiled tubules, the convoluted seminiferous tubules, that produce the sperms by a process called spermatogenesis.

15. In the mediastinum testis the convoluted seminiferous tubules join to form the straight seminiferous tubules which enter the fibrous tissue of the mediastinum testis. They then form the rete testis. At the upper end of the mediastinum testis the rete testis terminate in 12～15 efferent ductules of testis, passing from the testis to the epididymis.

16. 4. The function of testes
After puberty the testes produce sperms and secrete male hormone.

17. Ⅱ) The Epididymis 1. Location of epididymis
It is attached to the superior extremity and the posterolateral surface of the testis.

19. 2. Morphological feature of epididymis
The epididymis is comma—shaped and is divided into the head, body and tail.
Head: The enlarged superior portion of the epididymis is known as the head.
Body: The portion posterior to the testis is called the body.
Tail: The inferior portion is referred to as the tail.
The head of the epididymis contains the efferent ductules which terminate in a coiled duct of epididymis within the body and tail. The end of the duct of epididymis passes upward to continue with the ductus deferens.

21. 3. Function of epididymis
The epididymis is the principal store—house for sperms. It also adds an essential secretion to the seminal fluid in which the sperms are developed and activated.

22. Ⅲ) The Ductus Deferens
It is a continuation of the duct of epididymis, about 50 cm long. The ductus is divided into four parts:
1. The testicular part
It begins at the tail of epididymis, and ascends on the medial side of the epididymis, posterior to the testis.

24. 2. The funicular (spermatic) part
It extends from the superior extremity of the testis to the superficial inguinal ring.
It lies in medial and posterior portion of the spermatic cord and can be palpated easily in the living body.
This part is the place where the vasectomy is performed.

25. 3. The inguinal part
It passes through the inguinal canal from the superficial ring to the deep ring.

26. 4. The pelvic part
It enters the abdominal cavity from the deep ring of the inguinal canal. Then passes downward and medially along the lateral wall of the pelvis. It crosses over the terminal portion of the ureter anterosuperioly to its medial side.
The terminal portion of the ductus dererens is dilated, and called the ampulla ductus deferentis as it descends behind the fundus of the bladder. Its end is thin and joins the excretory duct of the seminal vesicle to form the ejaculatory duct.

27. The Spermatic Cord
When the testis descends through the abdominal wall into the scrotum, it carries its vessels and nerves and ductus deferens with it. These structures meet at the deep inguinal ring and together form the spermatic cord.

30. It extends from superior extremity of the testis to the deep inguinal ring, 11～15 cm in length.
The main structures of spermatic cord are the ductus deferens, testicular artery, pampiniform plexus of vein, nervous plexus, lymphatic vessels and the vestige of vaginal process.

32. Ⅳ) The Ejaculatory Duct
It is formed by the union of the terminal part of the ductus deferens and the excretory duct of seminal vesicle.
It commences at the base of prostate, and passes downward and forward to open into the prostatic portion of the urethra.

34. Ⅴ) The Seminal Vesicles
They are two oval sacculated organs placed posterior to the fundus of urinary bladder, lateral to the ampulla ductus dererentis and in front of the rectum.
Its excretory duct joins the corresponding ductus deferens to form the ejaculatory duct.
The secretion of the seminal vesicles is a component of seminal fluid.

36. Ⅵ) The Prostate
It is a single, firm gland consisting of muscular and glandular tissues.
Function:
Its secretion, the important component of the seminal fluid, is conveyed into the prostatic portion of urethra through 16～32 excretory ducts.

38. 1. Location
The prostate lies in the lesser pelvic cavity, below the urinary bladder and around the superior part of the urethra, between the bladder and the urogenital diaphragm. It is in front of the rectum, posterior to the pubic symphysis.

39. 2. External Features:
The prostate is chestnut-shaped and has an apex, a base.
The apex of prostate is inferior and rests on the urogenital diaphragm.
The base is superior and is against the neck of bladder.
The urethra passes through the prostate.
The anterior surface of prostate is posterior to the pubic symphysis.
There is a shallow sulcus, called prostatic sulcus, along the midline of the posterior surface. This sulcus, apmula ductus deferentis and seminal vesicles can be palpated through the anterior wall of the rectum in the living body.

41. The lobes of prostate:
The prostate may be divided into five lobes:
anterior, median, posterior and two lateral lobes.
The median lobe (isthmus of prostate) lies behind the urethra, between the right and left lobes, in front of the posterior lobe.
In old men, the prostate sometimes enlarges and bulges into the lumen of urethra causing obstruction of it.

42. Ⅶ) The Bulbourethral Glands (of Cowper)
They are about the size of pea, one on each side of the membranous part of urethra, embedded in the deep transverse muscle of perineum. Their excretory ducts open into the upper part of the spongy part of urethra.

44. The seminal fluid is the mixture of the sperms and secretion of accessory glands. It is white milk like fluid, with weak alkalinity. In every ejaculation about 2～5 ml of seminal fluid is expelled, which contains 300～500 million of sperms

45. Ⅱ. The External Genital Organs
Ⅰ) The Scrotum
It is a pendulous pouch of skin and superficial fascia evaginated from the lowed part of the abdominal wall.
The scrotal wall is composed of skin and dartos.

46. ① The skin: The skin is thin and extensible, which contains few hairs, but many sebaceous and sweat glands, pigment cells and nerves.
② The dartos: Involuntary muscle fibers lie within the superficial fascia of the scrotum to form the dartos. The contraction of dartos causes the scrotal skin wrinkle when cold. Beneath the dartos there are three layers of tunics to enclose the testis and spermatic cord, that is the external spermatic fascia, the cremaster and the internal spermatic fascia.

48. ③ The external spermatic fascia: It is the continuation of the aponeurosis of the obliquus externus abdominis.
④ The cremaster: It is the middle layer coming from the obliquus internus abdominis and transversus abdominis.
⑤ The internal spermatic fascia: It is the continuation of the transverse fascia.

49. ⑥ The tunica vaginalis of testis: It is from the peritoneum
⑥ The tunica vaginalis of testis: It is from the peritoneum. The tunica vaginalis is the remnant of the lower end of the vaginal process, the upper part of which is obliterated. The tunica vaginalis consists of visceral layer and perietal layer. Between these two layers there is a serous cavity with few fluid in it. If the upper part of the vaginal process is not obliterated, the serous cavity of testis communicates with the abdominal cavity, and the herniated abdominal content, such as loop of ileum will enter the serous cavity close to the testis. This case is called the congenital indirect inguinal hernia.

50. Ⅱ) The Penis It is the male organ of copulation and urination.
It comprises a root, a body and a head.
The root of penis is the posterior portion and attaches to the pubic arch.
The body continuing with the root is the movable part, and is covered with skin and fascia.
The head of penis is a slightly enlarged portion called the glans penis, which is separated from the body by a constriction, the neck of penis. A median slit at the tip of the glans is the external orifice of urethra.

52. At the neck, the skin is folded upon itself to form the prepuce
At the neck, the skin is folded upon itself to form the prepuce. The free border of the prepuce is called the orifice of prepuce. The prepuce in the child is longer than in the adult, and the diameter of the orifice of prepuce is smaller than in adult. In some cases, the prepuce is longer than normal (redundant prepuce) or the orifice of prepuce is smaller than normal and the prepuce cannot be retracted over the glans (phimosis). This may permit accumulation of the secretions beneath the prepuce, leading to inflammation. And it is now generally believed that chronic inflammation of the prepuce predisposes to carcinoma of the glans penis. For these reasons prophylactic circumcision is commonly practiced.

53. The frenulum of prepuce is a median fold passing from the deep surface of the prepuce to a point near the external orifice of urethra ventrally. It must be protected during circumcision.
Structure of the penis:
Structurally the penis is composed of three cylindrical masses of erectile tissue.
Cavernous body of penis: The two dorsally located masses are called the cavernous body of penis.
Cavernous body of urethra: The single smaller ventral mass, the cavernous body of urethra, contains the spongy part of the urethra.

55. Ⅲ) The Male Urethra
It extends from the internal orifice of urethra in the urinary bladder to external orifice at the end of the penis. It is 17—20 cm long and may be divided into three parts:

56. 1. The prostatic part
It is about 2.5 cm in length with the largest caliber.
On the midline of posterior wall there is a longitudinal ridge, urethral crest. At the middle portion of the urethral crest there is a small prominence, seminal colliculus, lateral to which is the opening of ejaculatory duct. The prostatic ductules open into the urethra near the crest.

58. 2. The membranous part
It is 1—2 cm in length, and is the shortest, least dilatable and narrowest part of the urethra. It is within the urogenital diaphragm, and surrounded by the sphincter of urethra.
This striate muscle is under voluntary control after early infancy.
Anterior ruethra and posterior urethra:
In the clinic the first and second parts of urethra are called the posterior urethra, and the last spongy part the anterior urethra.

59. 3. The cavernous (spongy) part
It is contained in the cavernous body of urethra, about 15 cm in length. It extends from the end of the membranous part to the external orifice of urethra.
In this part there are two dilated places. One is at the proximal portion within the bulb of penis, called the bulbous portion of urethra, which is the common site of rupture in straddle injuries. The other is near the external orifice of urethra, the navicular fassa.

60. The male urethra presents three strictures, three dilatations and two curvatures.
The three strictures are situated in:
① The internal urethral orifice,
② The membranous portion
③ The external orifice of urethra.

62. Three dilatations:
The three dilatations are situated in:
① The prostatic part of urethra.
② The bulbous portion of urethra
③ Navicular fossa of urethra.

63. Two curvatures:
When the penis is flaccid, the urethra has a course of the letter “S”.
① The subpubic curvature is a ventrally and upwards concave curve.
② The prepubic curvature is a dorsally and downwards concave curve.