male gen human biology.pdf

Humane Biology MALE GENITAL ORGANS Y1 Prof. Talib Jawad...

Humane Biology MALE GENITAL ORGANS Y1 Prof. Talib Jawad 2024 ‫ ص‬06:57 16/04/2024 ejaculatory duct anatomy - Search Images (bing.com)  Testis The testis is a firm, mobile organ lying within the scrotum. It is common for the right testis to hang lower than the left in approximately 85% of men. The dimensions of the normal testis include a length of 4 to 5 cm, a width of 3 cm, and a depth of 2.5 cm; Volume of 15 to 25 mL. Shape: ovoid and white. A tough fibrous capsule, the tunica albuginea, surrounds each testis. Seminephrus tubule  A series of fibrous septa extend from the inner surface of the capsule and divide the interior of the organ into lobules. One to three coiled seminiferous tubules lie within each lobule. The tubules open into a network of channels called the rete testis. Small efferent ductules connect the rete testis to the upper end of the epididymis.  Epididymis  The epididymis is a firm structure lying posterior to the testis, with the vas deferens lying on its medial side. It has an expanded upper end, the head, a body, and a pointed tail inferiorly.  The epididymis is a much-coiled tube nearly 20 ft (6 m) long, embedded in connective tissue. The tube emerges from the tail of the epididymis as the vas deferens, which enters the spermatic cord. The long length of the duct of the epididymis provides storage space for the spermatozoa and allows them to mature  Vas Deferens (Ductus Deferens)  The vas deferens is a thick-walled tube about 18 in. (45 cm) long that conveys mature sperm from the epididymis to the ejaculatory duct and the urethra.  It arises from the tail (lower end) of the epididymis and passes through the inguinal canal. The vas deferens then runs on the posterior surface of the bladder. The terminal part of the vas deferens is dilated to form the ampulla of the vas deferens  Seminal Vesicles The seminal vesicles are two lobulated organs about 2 in. (5 cm) long lying on the base of the bladder. Each seminal vesicle consists of a much-coiled tube embedded in connective tissue. The terminal part of the vas deferens lays on the medial side of each vesicle. Inferiorly, each seminal vesicle narrows and joins the vas deferens of the same side to form the ejaculatory duct.  Ejaculatory Duct Each ejaculatory duct is (2.5 cm) long and is formed by the union of the vas deferens and the duct of the seminal vesicle. The ejaculatory duct pierces the posterior surface of the prostate and opens into the prostatic part of the urethra. Its function is to drain the seminal fluid into the prostatic urethra.  Prostate Gland  The normal prostate gland is ovoid and measures 3 cm in length, 4 cm in width, and 2 cm in depth; it has a weight of 18 to 20 g  The prostate is a fibromuscular glandular organ that surrounds the prostatic urethra. It lies between the neck of the bladder above and the urogenital diaphragm below.  The numerous glands of the prostate are embedded in a mixture of smooth muscle and connective tissue, and their ducts open into the prostatic urethra. Prostate Gland  Sperm produced by the testes mature within the epididymis.  Maturation seems to be required for sperm to swim to the egg.  When sperm leave an epididymis, they enter a vas deferens, also called the ductus deferens.  The sperm may be stored for a time in the vas deferens. Each vas deferens empties into an ejaculatory duct. The ejaculatory ducts enter the urethra.  At the time of ejaculation, sperm leave the penis in a fluid called semen. The seminal vesicles, the prostate gland, and the bulbourethral glands (Cowper glands) add secretions to seminal fluid.  Each component of seminal fluid seems to have a particular function.  Sperm are more viable in a basic solution; seminal fluid, milky in appearance, has a slightly basic pH (about 7.5).  Swimming sperm require energy; and seminal fluid contains the sugar fructose, which presumably serves as an energy source.  Semen also contains prostaglandins, chemicals that cause the uterus to contract.  Some investigators believe that uterine contractions help propel the sperm toward the egg.  Scrotum The wall of the scrotum has four layers: 1. Skin 3. Spermatic fasciae 2. Superficial fascia 4. Tunica vaginalis  Spermatic Cord The spermatic cord is a bundle of structures that pass through the inguinal canal to and from the testis. It begins at the deep inguinal ring lateral to the inferior epigastric artery and ends at the testis.  The penis is the male organ of Penis sexual intercourse. The penis has a long shaft and an enlarged tip called the glans penis. The glans penis is normally covered by a layer of skin called the foreskin.  Circumcision, the surgical removal of the foreskin, if done, is usually performed soon after birth.  The penis has a fixed root and a body that hangs free  Penile Root The root of the penis is made up of three masses of erectile tissue: the bulb of the penis and the right and left crura of the penis.  Penile Root The bulb continues forward into the body of the penis and forms the corpus spongiosum. The two crura converge anteriorly and come to lie side by side in the dorsal part of the body of the penis, forming the corpora cavernosa.  Penile Body  The essential components of the body of the penis are three cylinders of erectile tissue enclosed in a tubular sheath of deep fascia (Buck’s fascia).  The erectile tissues are the two dorsally placed corpora cavernosa and the single corpus spongiosum that is applied to their ventral surface. The corpus spongiosum expands at its distal extremity to form the glans penis, which covers the distal ends of the corpora cavernosa. thanks