Module 3
1. Module 3
1.15. Page 5
Module 3—The Male and Female Reproductive Systems
Lesson Summary
In Lesson 3 you investigated the following focusing questions:
-
How do sperm and egg cells develop into functional gametes?
-
What supporting structures help in the development of a fully functional gamete?
Human reproductive systems are uniquely designed to develop properly functioning gametes, thereby ensuring continuation of the human species. In the male reproductive system, the male gonads (the testes) produce the functional gametes (the sperm) in the seminiferous tubules. The Sertoli cells give both structural and secretory support to the developing sperm. Structural support is provided by protecting the developing sperm from the body’s immune system, and secretory support is provided by secreting the hormone inhibin. The interstitial cells, also found in the seminiferous tubules, indirectly support sperm production by secreting the hormone testosterone. Testosterone then stimulates the process of spermatogenesis to develop the sperm.
The female gamete, the egg, is produced in the ovary and provided with structural and secretory support. Follicles provide structural support by surrounding the primary oocyte, helping to nourish, protect, and develop the egg cell. Follicles also offer secretory support by releasing estrogen and some progesterone. These hormones then help to develop the primary oocyte into a mature egg that is ready for ovulation.
Continuation of the species is ensured when these two properly formed gametes are joined through fertilization.
Lesson Glossary
Consult the glossary in the textbook for other definitions that you may need to complete your work.
corpus luteum: the structure that develops from a matured follicle that has released its egg
The corpus luteum produces progesterone and some estrogen. If pregnancy does not occur, the corpus luteum degenerates.
gametogenesis: the process of creating gametes from somatic cells; includes meiosis
inhibin: a hormone produced by Sertoli cells during spermatogenesis that inhibits GnRH, preventing excessive sperm production
interstitial cells: tightly packed testosterone-secreting cells that surround the seminiferous tubules in the testes
oligospermia (oligozoospermia): a condition in which there are less than 20 million spermatozoa per millilitre of semen
oocytes: cells that are undergoing meiosis in the ovary
oogenesis: the process of egg production in females
oogonia: diploid cells in the ovary that will undergo meiosis
primary oocytes: cells in the first meiotic division of oogenesis
somatic cell: a normal diploid body cell; a cell not involved in fertilization
spermatogenesis: the process of sperm production in males
spermatozoa: mature sperm stored in the epididymis