Reproductive System Topics

• male and female reproductive system
• intermediate mesoderm
• egg laying mammals
• male and female reproductive systems
• female reproductive systems
• male gamete
• female reproductive system
• male reproductive system
• reproductive organs
• wolffian duct
• analogous structures
• fallopian tubes
• molecular mechanisms
• project inventory
• reproductive development
• reproductive organ
• epididymis
• vas deferens
• spermatozoa
• organ systems

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Reproductive System, Reproductive System

Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system.

The primary direct function of the male reproductive system is to provide the male gamete or spermatozoa for fertilization of the ovum.

The human female reproductive system contains three main parts: the vagina, which acts as the receptacle for the male's sperm, the uterus, which holds the developing fetus, and the ovaries, which produce the female's ova. The breasts are also an important reproductive organ during the parenting stage of reproduction.

Despite the differences between the adult male and female reproductive system, there are a number of homologous structures shared between them due to their common origins within the fetus. Both organ systems are derived from the intermediate mesoderm. The three main fetal precursors of the reproductive organs are the Wolffian duct, Mllerian ducts, and the gonad. Endocrine hormones are a well known and critical controlling factor in the normal differentiation of the reproductive system. [http://www.epa.gov/endocrine/inventory/RTD-KELC.html EDRI Federal Project Inventory:Cellular and Molecular Mechanisms of Abnormal Reproductive Development] US EPA. Dr. William R. Kelce.

In both sexes the gonad goes on to form the testes and ovaries, because they are derived from the same undeveloped structure they are considered homologous organs. There are a number of other homologous structures shared between male and female reproductive systems. However, despite the similarity in function of the female fallopian tubes and the male epididymis and vas deferens, they are not homologous but rather analogous structures as they arise from different fetal structures.

Monotremes (i.e. platypus and echidnas), a group of egg-laying mammals, also lack a uterus and vagina, and in that respect have a reproductive system resembling that of a reptile.

Source: Wikipedia > Reproductive System