1. Vasectomy (Male Sterilization) Session II: Anatomy and Physiology of the Male Reproductive System

2. Session Objectives
By the end of the session, participants will be able to
Describe the male genito-urinary anatomy and physiology
Describe the anatomy of the spermatic cord and its internal structures
Explain the effects of vasectomy on male reproductive anatomy and physiology
Show this slide and review the session objectives.
This session covers the following topics:
Anatomy of the external and internal male reproductive organs
The structure of the spermatic cord
Anatomical conditions of significance for vasectomy
The physiology of the male reproductive system

3. Anatomy of the Male Reproductive Organs
Post/project the diagram in the front of the room.
Ask:
Please identify all of the parts on this diagram of the male internal and external reproductive system and state one aspect of the identified organ that is relevant to vasectomy, where applicable.
Inform them that they have four minutes to complete the exercise.
They may use their notebooks to write down their responses.
At the end of four minutes, call all participants to plenary and ask for responses from volunteers.
They should name the anatomical structures and mention one aspect of the structure relevant to vasectomy.
Possible responses should include the following:
Ureters—An internal organ with no direct anatomical significance for or relevance to vasectomy.
Bladder—An internal organ with no anatomical significance for or relevance to vasectomy.
Seminal vesicles—Internal structures that continue to produce seminal fluids, which form the bulk of ejaculate after vasectomy.
Prostate gland—Internal structure that continues to function normally after vasectomy, producing prostatic fluids that contribute to ejaculatory fluids but otherwise has no direct relationship to vasectomy.
Vas deferentia—Internal structures within the scrotum that must be identified, isolated, and excised and ligated during vasectomy, thereby interrupting the flow of sperm and this is what makes vasectomy  to the effective, three month after the procedure.  “Contributing” seems to underplay it—this step _is_ what makes vasectomy effective, isn’t it?
Epididymis—Internal structures important in the development of sperm. The surgeon must make the incision in the right place to avoid injury to these organs. After vasectomy, these tubules may become engorged with sperm and may rupture.
Scrotal sac—An important structure that contains the vas deferens, testis, and spermatic cord, among others—all structures relevant to vasectomy. Any scars or deformities, swelling, masses, anomalies of the blood vessels (e.g., varices) or accumulation of fluid are significant and have implications for the planning of the procedure.
Testes--Both testes must be identified before vasectomy, as the absence of one or both, the locations of these structures, any deformities or swelling, and their mobility will have implications for the vasectomy procedure
Urethra—The conduit for passing both semen and urine out of the body (during ejaculation and urination, respectively). However, it has no direct relation with the vasectomy procedure itself. The surgeon must examine this structure to ensure that there is no evidence of infection or bleeding, etc., as part of the client evaluation.
As the participants share their responses, correct these as appropriate.
Wrap up the session by stating that during the next session, you will review some of these anatomical structures in detail.

4. Male External Reproductive Organs
Principal external organs:
Penis
Scrotum
Show this slide and state the following:
The two principal external organs of the male reproductive system are the penis and the scrotum.
The penis contains the urethra and specialized, highly vascularized tissue to achieve an erection.
The scrotum is divided into two scrotal sacs, each containing a testis and an epididymis.
Emphasize the following: During vasectomy, a puncture is made in the scrotum to allow the surgeon access to the vasa (ductus) deferentia. The opening is made midway between the base of the penis and the top of the testes, on the median raphe. This puncture site is chosen because (1) it allows easy access to the vasa through the scrotal sac, and (2) it avoids risk of injury to the epididymis and the testicles.

5. Internal Male Organs Made up of three groups Testis Ducts
Accessory glands
Show this slide and state the following:
The male internal reproductive organs are made of three groups—namely, the testis, the ducts, and the accessory glands.
The testes (also called testicles or male gonads) produce sperm and the male sex hormone testosterone. Emphasize that after vasectomy, the testes continue to produce both sperm and hormones.
The ducts group consist of the epididymides, the vasa deferentia, the ejaculatory ducts, and the urethra. The two epididymides (which begin at the testes) are each connected to one of the vasa deferentia. Each vas ends at the base of the prostate, where it is joined by ducts from the seminal vesicle. Together, each vas and duct from a seminal vesicle forms an ejaculatory duct (not pictured). The two ejaculatory ducts open into the urethra to allow the passage of sperm and seminal fluid during ejaculation. You will learn how to palpate the cord to identify and secure the vas using the three-finger technique, with this technique you can easily feel the vas as a firm cord like structure by rolling the spermatic cord between your thumb and third finger. 
The accessory glands include the seminal vesicles, the prostate, and the bulbourethral glands (not pictured). These glands empty their secretions, which contribute to the seminal fluid, into the urethra. The seminal fluid carries sperm through the urethra during ejaculation. The urethra also carries urine.

6. The Male Reproductive System
Penis
Seminal vesicles
Urethra
Prostate
Use the slide to summarize the male external and internal reproductive organs
Vas deferens
Foreskin
Testicles
Scrotum
Source WHO Decision Making tool for FP clients and service providers

7. 6: The Male Reproductive System
Penis Male sex organ made of spongy tissue. When a man becomes sexually excited, it stiffens and grows larger. Semen, containing sperm, is released from the penis during sexual intercourse (ejaculation).
Seminal vesicles Where sperm is mixed with semen.
Prostate A reproductive organ that produces a fluid to help sperm move.
Urethra Tube through which semen and sperm are released from the body. Urine is released through the same tube.
Vas deferens Two thin tubes that carry sperm from the testicles to the seminal vesicles. Vasectomy blocks these tubes.
Foreskin Hood of skin covering the end of the penis. Circumcision removes the foreskin.
Testicles Organs producing sperm.
Scrotum Sack of thin loose skin containing the testicles.

8. Spermatic Cord
The vas deferens is one of the structures of the spermatic cord.
Others are shown in the diagram.
Show this slide and explain the following
One of the first steps in vasectomy is to identify the vas deferens, so that it can be anesthetized and occluded. During the injection of local anesthetic and during NSV, care should be taken to avoid the testicular artery and veins located within the internal spermatic fascia.
The vas deferens is located within the spermatic cord. It can be easily palpated and differentiated from other structures in the cord (the spermatic fascia, arteries, and veins), as it is a firm, thick structure within the spermatic cord.
The internal spermatic fascia forms a sheath around the vas and has important structures, such as the blood supply to the vas, which are commonly severed during vasectomy leading to hematoma formation. The internal spermatic fascia is the sheath or structure is used to separate the testicular and prostatic ends of the vas by a technique referred to as fascial interposition . You will learn how to perform the fascial interposition later in the course.
The vas is approximately 35 cm long and 2–3 mm in diameter. The small diameter of the lumen of the vas presents the main challenge to vasectomy reversal. Without microsurgical techniques, the success of vasectomy reversal is low (pregnancy rates range from 35% to 57%). Even when microsurgical techniques are used, success is often limited (the success rate of microsurgical techniques is between 38% and 82%).
Cross-section of the spermatic cord
Source: EngenderHealth

9. Anatomical Conditions of Significance
Undescended testis
Hydrocele
Inguinal hernia
Aberrant vas
Display slide
Explain
Anatomical variations are characteristic of the following conditions; if they are diagnosed, the provider may need to take certain precautions or refer the client for specialized care by a highly skilled surgeon. Such conditions therefore, tend to influence where and when the client can have a vasectomy. These conditions include:
Undescended testis—A condition where one testis or both testes are located in the inguinal region or in the abdomen, instead of in the scrotum. This occurs when there are problems with the descent of the testis from the abdomen to the scrotum. Problems during the development process early in life may contribute to the failure of complete descent into the scrotum. If this problem is diagnosed during the client evaluation, the provider should refer the client to a highly skilled surgeon for care.
Hydrocele—This literally means fluid in the scrotal sac. The condition may be congenital or may be caused by parasitic infestation, among others. If diagnosed with hydrocele, the client must be managed by a skilled surgeon or referred to a facility where he can receive appropriate care and have the vasectomy.
Inguinal hernia—In this condition, there is a defect in the integrity of the abdominal wall in the inguinal region, leading to partial or complete protrusion of some of the abdominal viscera through the defect. If this problem is identified, it is recommended that the vasectomy procedure and surgery for herniorrhaphy be planned and performed at the same time.
Aberrant vas—Although extremely rare, an aberrant vas (or a third vas that is a result of a congenital anomaly), if not diagnosed during vasectomy, may present as a case vasectomy failure

10. Physiological Changes after Vasectomy
Sexual and reproductive physiology remains unaffected except for desired change in fertility.
Erection is not affected.
Ejaculation is not affected.
Sexual drive is not affected.
Sperm production is not affected.
Sperm count in the ejaculate semen is drastically reduced by three months afterward.
Serum antisperm antibodies rises.
There are no long-term negative health effects.
Display slide
Explain:
After vasectomy, the male sexual and reproductive physiology remains unaffected, aside from the desired change in fertility.
The nerves involved in erection are not disrupted during vasectomy. Seminal fluid, which forms the largest part of ejaculatory fluid, continues to be produced. As a result, the client will not notice any reduction in the amount of ejaculatory fluid.
Sperm production continues, even though the sperm’s passage through the reproductive system has been blocked. These sperm are absorbed into the tissue and tubes of the epididymis. Sometimes sperm blockage causes pressure to build up in the epididymis and its tubes, causing these structures to distend and, in time, rupture. Such ruptures are usually asymptomatic and not problematic. The sperm granulomas that can form at the site of the rupture do not usually require treatment. These may be felt as small nodules in the scrotum.
Sexual drive, which is a physiological process, also is not affected by vasectomy.
Vasectomy causes a breakdown in the blood-testes barrier, which leads to increased levels of sperm antigen and antisperm antibodies in the serum of most men who have had a vasectomy. Factors influencing the development of antisperm antibodies in vasectomized men are unknown. Studies have shown no association of these antibodies with problems in humans.
Over the years, some concerns have been raised about possible negative health consequences of vasectomy. However, large, well-designed studies have consistently shown no adverse effects of vasectomy on the risks of heart disease, testicular or prostate cancer, immune system disorders, and a host of other conditions. Men requesting the procedure can thus be reassured that no substantial long-term health risks are associated with the procedure.