The testes are enclosed in the scrotal sac which is lined with a smooth muscle layer called the dartos muscle. This muscle contracts when the temperatures drop near the testes, causing them to withdraw closer to the body where it is warmer. Another muscle of the region is the cremaster muscle. It also contracts when it is cold but it is made of skeletal muscle. The epididymis sits on top of the testis like a small cap and is a place where sperm cells mature. The spermatic cord consists of the cremaster muscle, the ductus deferens, the testicular artery, and a complex meshwork of veins called the pampiniform plexus. This plexus cools arterial blood flowing to the testes maintaining the testes at about 35 degrees C which is important for proper sperm maturation.
The sperm are produced in the seminiferous tubules of the testis. This occurs in lobules of the testis before they move to the epididymis. The epididymis has a series of long coiled tubules called the ductus epididymis and the sperm cells slowly pass through this ductwork. After the sperm cells mature in the epididymis they then travel to the ductus deferens which loops around the ureters before reaching the seminal vesicles located on the posterior surface of the urinary bladder. The seminal vesicles add a fluid that has buffers and that provides fructose to the sperm cells. From the seminal vesicles the fluid passes through the ejaculatory duct to the prostate. The prostate adds further fluid that is rich in buffers. This fluid passes into the urethra. The bulbourethral glands add a protein lubricant to the fluid. Label the organs and their features in the illustration and color them in different colors.
Answer Key: a. Ductus deferens, b. Pampiniform plexus, c. Testicular artery, d. Epididymis, e. Testis, f. Cremaster muscle and fascia, g. Scrotal skin and dartos muscle, h. Ureter, i. Urinary bladder, j. Seminal vesicle, k. Ejaculatory duct, I. Prostate, m. Bulbourethral gland, n. Urethra, o. Ductus epididymis, p. Lobules of testis
Chapter Thirteen kaplanl. . Male Reproductive System medical
MIDSAGITTAL SECTION OF PELVIS/CROSS SECTION OF PENIS AND SEMINIFEROUS TUBULES
When seen in a midsagittal section, the relationship of the glands that produce seminal fluid can easily be seen. The prostate is approximately the size of a golf ball and is located inferior to the urinary bladder. The prostatic urethra is the portion of the urethra that is enclosed in the prostate. The bulbourethral glands are located in the wall of the pelvic floor and the seminal vesicles are posterior to the urinary bladder. Exterior to the body wall are the testes and these are enclosed in the scrotal sac. The epididymis receives sperm from the testis and has three parts, a head, a body, and a tail. The symphysis pubis is an important reference point in the midsagittal section. In males there is a flap of tissue encircling the glans penis. This is the prepuce (foreskin) and it is sometimes removed at birth in a procedure called a circumcision. The corpus cavernosum can be seen in this section along with the corpus spongiosum and the spongy urethra.
The cross section of the penis illustrates the relative position of the erectile tissue in the male. On the dorsal aspect of the penis are the paired corpora cavernosa (corpus cavernosum singular). These cylinders fill with blood and produce an increase in length and diameter of the penis. These, along with the corpus spongiosum, are involved in making the penis erect. The corpus spongiosum contains the spongy urethra. The deep dorsal vein of the penis is also seen in cross section. Label the structures seen in a cross section of the penis and color in the erectile tissue and the spongy urethra.
The formation of sperm is known as spermatogenesis and occurs from spermatogonia on the superficial wall of the seminiferous tubules. These produce cells called primary spermatocytes which in turn mature into secondary spermatocytes. Spermatids derive from secondary spermatocytes and they, in turn, become spermatozoa (sperm cells). Sertoli cells assist in the process. Label the cells and color each one in a separate color.
Answer Key: a. Urinary bladder, b. Symphysis pubis, c. Corpus cavernosum, d. Corpus spongiosum, e. Glans penis, f. Prepuce, g. Testis, h. Tail of epididymis, i. Body of epididymis, j. Head of epididymis, k. Spongy urethra, I. Bulbourethral gland, m. Prostate, n. Seminal vesicle, o. Deep dorsal vein, p. Spermatozoa, q. Spermatids, r. Secondary spermatocytes, s. Primary spermatocytes, t. Sertoli cell, u. Spermatogonia
Was this article helpful?
How to increase your staying power to extend your pleasure-and hers. There are many techniques, exercises and even devices, aids, and drugs to help you last longer in the bedroom. However, in most cases, the main reason most guys don't last long is due to what's going on in their minds, not their bodies.