This article is semi-male reproductive system anatomy and physiology pdf until February 9, 2020. This article is about the reproductive system in human males.
Erection occurs because sinuses within the erectile tissue of the penis become filled with blood. The scrotum is a pouch-like structure that hangs behind the penis. It holds and protects the testicles. It also contains numerous nerves and blood vessels. Cremaster and Dartos muscles relax to bring down the scrotum away from the body and remove the wrinkles respectively. The scrotum remains connected with the abdomen or pelvic cavity by the inguinal canal.
The spermatic cord, formed from spermatic artery, vein and nerve bound together with connective tissue passes into the testis through inguinal canal. Image showing innervation and blood-supply of the human external male genitalia. It carries the spermatozoa from the epididymis to ejaculatory duct. The embryonic and prenatal development of the male reproductive system is the process whereby the reproductive organs grow, mature and are established.
It begins with a single fertilized egg and culminates 38 weeks later with birth of a male child. The development of the male reproductive system coincides with the urinary system. A sperm cell carrying a Y chromosome results in an XY combination, and a male child will develop. Genetic sex determines whether the gonads will be testes or ovaries. In the developing embryo if the testes are developed, it will produce and secrete male sex hormones during late embryonic development and cause the secondary sex organs of the male to develop.
The prostate gland derives from the urogenital sinus, and the other embryonic structures differentiate into the external genitalia. In the absence of testicular secretions, the female genitalia are formed. At six weeks post conception, the differentiation of the external genitalia in the male and female has not taken place. At eight weeks, a distinct phallus is present during the indifferent stage. By the 10th-12th week, the genitalia are distinctly male or female being and derived from their homologous structures. At 16 weeks post conception, the genitalia are formed and distinct. The masculinization of the embryonic reproductive structures occurs as a result of testosterone secreted by the embryonic testes.