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Introduction to human embryology
Published on November 30, 2022 49 min
A selection of talks on Physiology & Anatomy
I'm Dr. Banumathy, Anatomist from Tamil Nadu, India. The topic for discussion today is "Introduction to Human Embryology".
The development of human beings before birth of the child is called prenatal development. The development after birth is postnatal development. The study of the developmental anatomy in the prenatal period is embryology.
Human development commences from a single cell zygote. The zygote is formed by the union of two highly specialized cells. The male gametes are the sperms and the female gametes are the ova. The sperms are produced in the testes and the ova are formed in the ovary. The development of the gonads depends on the gonadotrophic hormones of the pituitary gland.
The gonads, testis in males and ovary in females develop from the genital ridge of the intermediate mesoderm. However, the primordial sex cells are derived from the endoderm of the hindgut. These cells migrate to the developing gonads.
The male gonads are testis. They are paired organs situated in the skin pouch scrotum. Each testis is oval in shape and is covered by a capsule tunica albugenia testis. Numerous fibrous bands divide the testis into lobules. In each lobule are present three or four white string-like structures called the seminiferous tubules. Spermatogenesis takes place in the seminiferous tubules. The sperms are transported to the exterior through the epididymis, vas deferens, ejaculatory duct, urethra and external urethral orifice.