Male internal genital organ

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1. MALE INTERNAL GENITAL ORGANS

2. Introduction The male genital organs are divided into two groups: internal and external. The internal genital organs include: 1. Testes and epididymis. 2. Prostate. 3. Bulbourethral glands. 4. Seminal vesicles. 5. Ejaculatory ducts and penis. 6. Vasa deferentia (deferent ducts).

3. TESTIS The testis is a male gonad. It is homologous with the ovary in the female. It is a mobile organ and lies in each half of the scrotal sac. The functions of the testis include production of spermatozoa and secretion of testosterone (or dihydrotestosterone ). Male hormone, responsible for the development and maintenance of the secondary sex characteristics of the maleness.

4. SHAPE AND MEASUREMENTS Shape:- It is oval/ellipsoid in shape (compressed from side to side). Measurement:- It measures approximately 4 3 2.5 cm (length 4 cm, breadth 2.5 cm, anteroposterior diameter 3 cm) and weight 10–15 g. POSITION IN THE SCROTUM The testis is suspended in the scrotum by the spermatic cord. It lies obliquely, so that its upper pole is tilted slightly forward and laterally, and lower pole backward and medially.

5. EXTERNAL FEATURES The testis presents the following external features: Two poles—upper and lower. Two borders—anterior and posterior. Two surfaces—medial and lateral.

6. COVERINGS Three coats cover the testis. From superficial to deep these are: 1. Tunica vaginalis . 2. Tunica albuginea . 3. Tunica vasculosa .

7. ARTERIAL SUPPLY:- The testicular artery supplies the testis, VENOUS DRAINAGE:- the testis form a plexus of veins called pampiniform plexus) drains the venous blood from the testis. they join to form a two testicular veins.

8. EPIDIDYMIS The epididymis is a comma-shaped structure, which lies on to the superior and posterolateral surface of the testis. It is made up of highly coiled tubes. PARTS:- The epididymis from above downward is divided into three parts: head, body, and tail. The head (the upper expanded part) is connected to the upper pole of testis by efferent ductules and consists of highly coiled efferent ductules . The body (middle part) and tail (lower period part) are made up of a single highly coiled duct of epididymis, which emerges from the tail as the vas deferens.

9. FUNCTIONS The functions of epididymis are: 1. Storage and maturation of spermatozoa. 2. Absorption of the fluid. 3. Addition of substances to the seminal fluid to nourish the maturating spermatozoa.

10. PROSTATE The prostate is a pyramidal-shaped, fibromuscular glandular organ which surrounds the prostatic urethra. The prostate gland secretes acid phosphatase, fibrinolysin , citric acid, amylase. Its secretions form the bulk of the seminal fluid. LOCATION:- The prostate is located in the lesser pelvis below the neck of the urinary bladder and above the urogenital diaphragm. It lies behind the lower part of the pubic symphysis and in front of the rectal ampulla.

11. SHAPE, SIZE, AND MEASUREMENTS:- The prostate is like an inverted cone in shape and resembles a chestnut in appearance. It presents the following measurements: Weight: 3 g. Width (at base): 4 cm. Length: 3 cm. Thickness: 2 cm. EXTERNAL FEATURES AND RELATIONS:- The prostate presents the following external features: 1. Apex. 2. Base. 3. Four surfaces (anterior, posterior and two inferolateral ).

12. LOBES OF THE PROSTATE:- The prostate is divided into five lobes: 1. Anterior lobe (isthmus). 2. Posterior lobe. 3. Median lobe. 4. Two lateral lobes.

13. STRUCTURES WITHIN THE PROSTATE:- These are as follows: 1. Prostatic urethra 2. Ejaculatory ducts 3. Prostatic utricle CAPSULES OF THE PROSTATE:- The prostatic capsules are two in number in normal gland and three in number if gland is affected by benign hypertrophy of the prostate. 1. True capsule: It is formed by the condensation of peripheral fibrous stroma. 2. False capsule (prostatic sheath): It is derived from the pelvic fascia.

14. ARTERIAL SUPPLY:- The prostate gland is supplied by the branches of inferior vesical , middle rectal, and internal pudendal arteries. VENOUS DRAINAGE:- The veins from the prostate form a rich venous plexus around the sides and base of the gland and occupy the space between the true and false capsules.

15. SEMINAL VESICLES The seminal vesicles are two coiled sacculated tubes about 2 inches (5 cm) long which can be unraveled to three times of this length. They lie extraperitoneally on each side, at the base of the urinary bladder, lateral to the termination of the vas deferens and in front of the rectum. The lower narrow end of seminal vesicle (duct of seminal vesicle) joins the ductus deferens to form the ejaculatory duct. The seminal vesicles, as their name implies, do not form a reservoir for sperms. Their secretions form a large amount of the seminal fluid. The secretion of seminal vesicles is slightly alkaline, containing fructose, choline, and a coagulating enzyme called vesiculose .

16. EJACULATORY DUCTS There are two ejaculatory ducts one on each side of the median plane at the lower part of the bladder base. Each duct traverses anteroinferiorly through the upper posterior half of the prostate and along the side of prostatic utricle to open in the posterior wall of prostatic urethra on the seminal colliculus ( verumontanum ) on either side of the opening of prostatic utricle.

17. VASA DEFERENTIA (DEFERENT DUCTS) VASA DEFERENTIA (DEFERENT DUCTS)These are two in number (right and left). Each vas deferens is a thick-walled muscular tube which transports spermatozoa from the epididymis to the ejaculatory duct. The vas deferens is about 18 inches (45 cm) long and has a narrow lumenexcept in the terminal part which is sacculated —the ampulla of vas deferens.

18. ARTERIAL SUPPLY:- The vas deferens is supplied by the following arteries: 1. Artery to vas deferens, a branch of superior vesical artery. 2. Artery to vas deferens, a branch of inferior vesical artery. 3. Artery to vas deferens, a branch of middle rectal artery. VENOUS DRAINAGE The veins from vas deferens join the vesical venous plexus which in turn drains into the internal iliac veins. NERVE SUPPLY It is primarily by the parasympathetic fibres from the pelvic splanchnic nerves.