16th February 2024

Reproductive system

Pelvic cavity

The inferior part of the abdominopelvic cavity is the pelvic cavity. The bony pelvis and pelvic muscles bound it. The lower spine (sacrum and coccyx) and hip bones form the bony pelvis. The hip bone combines three separate bones that fuse at puberty: ilium, ischium and pubis.

The pelvic cavity contains male and female reproductive organs, rectum, sigmoid colon, terminal coils of ileum, urinary bladder, distal ureters and urethra.

Male reproductive system

The male internal genital organs consist of vas deferens, ejaculatory ducts, seminal vesicles, prostate and urethra. The external parts of the male reproductive system include the penis, the scrotum and the testicles.

The testes are mobile ovoid organs (measuring about 12.5-19ml in volume) in the scrotum. Each test is covered by a thick fibrous layer known as tunica albuginea, which is covered by a thin visceral layer of tunica vaginalis. The testes produce male sex hormones and sperm. Seminiferous tubules produce the sperms within the testes. 

Epididymis is a long-convoluted tube closely related to the testes. It has three parts:  Head, body and tail. The head is the superior part which stores the sperm. The body connects the head to the tail. The tail of the epididymis then continues as vas deferens.

The vas deferens arise from the tail of the epididymis, travel within the spermatic cord, and cross the ureter and bladder. Each vas deferens converges with the duct from the seminal vesicle, forming ejaculatory ducts, which go through the prostate and empties into the prostatic urethra.

The prostate is located inferior to the neck of the urinary bladder. There are five lobes: prostate-anterior, median, right lateral, left lateral and posterior lobes. The prostatic urethra passes through the prostate and becomes the spongy urethra.

The penis is the male organ for sexual intercourse. It has three parts: The root, the shaft and the glans. The urethral opening is at the tip of the glans. The penis contains three erectile structures: corpora cavernosa (right and left) and corpus spongiosum. During an erection, these erectile structures become engorged with blood. The corpus spongiosum expands distally to become glans penis. The penis houses the spongy urethra.

The scrotum is the loose pouch-like sac of skin which houses the testes. It helps with the temperature regulation of the testes.

Female reproductive system

Female internal genital organs consist of ovaries, fallopian tubes, uterus and vagina. The ovary lies typically against the lateral wall of the pelvis. Each ovary is closely related to the distal part of the fallopian tube. The fallopian tube has five segments. From lateral to medial, these are Fimbriae-finger-like projections draping over the ovary, infundibulum, ampulla (usual site of fertilisation), isthmus and intramural parts. It extends from the uterus’s upper side to the ovary’s region. The uterus is a pear-shaped organ. This is divided into the fundus, body, and cervix. The cervix opens into the superior end of the vagina. The long axis of the uterus is typically bent forward at about a 90-degree angle to the long axis of the vagina, resulting in the anteversion of the uterus. 

The vagina extends superiorly and posteriorly from the vulva to the uterus. Its superior half lies above the pelvic floor, whereas the lower half lies within the perineum. The upper vaginal wall surrounds the cervix and forms the vaginal fornices. Two spaces are created by the peritoneal reflection over the urinary bladder, vagina and rectum, called the uterovesical and rectovaginal pouch (pouch of Douglas). The rectovaginal pouch is the most dependent part in females in an erect position. One peritoneal fold on each side extends from the uterus to the lateral pelvic wall, known as the broad ligament.

References

Wineski, L. E., & Snell, R. S. (2019). Snell’s clinical anatomy by regions. 

Chaurasia, B. D. (2019). Human anatomy: Regional and applied, dissection and clinical. New Delhi, India: CBS Publishers & Distributors.

Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). Moore’s Clinically Orientated Anatomy (7th ed.). China: Lippincott.