Introduction to the Reproductive System

Learning Objectives

By the end of this section, you will be able to:

  • Describe the anatomy of the sperm (spermatocyte) and egg (oocyte) producing and conducting organs, including their accessory structures
  • Explain the role of pituitary hormones in reproductive function
  • Trace the path of a spermatocyte or oocyte through the reproductive system
  • Describe the process of spermatogenesis and oogenesis
  • Explain the changes that occur in the ovary during the ovarian cycle, and in the uterus during the uterine cycle
  • Describe the development and maturation of the sex organs and the emergence of physical characteristics that occur during puberty
This photo shows an oocyte.

Figure 1. Following a surge of luteinizing hormone (LH), a secondary oocyte (immature egg cell) will be released into the oviduct, where it will then be available to be fertilized by a spermatocyte. Ovulation marks the end of the follicular phase of the ovarian cycle and the start of the luteal phase.

The reproductive system plays an essential role in the production and transport of cells necessary to create a new, genetically unique individual.  The entire process that supports the development of these cells is driven by hormones released both by reproductive organs and by the pituitary gland.  Additionally, the hormones secreted by reproductive organs play an essential role in the growth and maintenance of the muscular and skeletal systems, and in the development of numerous other physical characteristics such as fat distribution, muscle mass, and vocal cord length.  Hormones associated with this body system play a part in producing various behaviors, from aggression and irritability to sexual desire.  Last but not least, for many the reproductive system has a social role in being a part of the relationship between individuals. So in terms of being named a “reproductive” system, the function of this body system is actually much more complex than to only produce offspring (as its name implies), especially since people possess these organs and hormones whether or not they ever reproduce!  That being said, much of the content of this particular chapter is focused on the role of these cells, organs, and hormones in terms of their potential use for reproduction, but keep in mind that they continue to perform the same functions whether or not they are used to this end.

You will note that the terms “female” and “male” are not used within this chapter.  This is because these terms, which refer to gender, do not necessarily represent the anatomical structures of those who identify with either, both, or neither of these genders.  A person who identifies as male can have egg producing and conducting organs, a person who identifies as female can have a Y chromosome.  For these reasons, the terms “male” and “female” in the realm of biology and medicine are not appropriate for describing human anatomy.  Instead, the terms “egg-producing and conducting organs”, “gestational organs” and “sperm-producing and conducting organs” will be used.  This vocabulary more completely and correctly describes the anatomical structures found in the human body.