Anatomy & Physiology

Anatomy & Physiology Study Guide

Chapter 25: The Reproductive System The reproductive system ensures the continued existence of the human species. It produces, stores, transports, and nourishes functional male and female reproductive cells called gametes . The reproductive system includes the gonads (the reproductive organs that produce gametes and hormones), ducts that receive and transport the gametes, accessory glands and organs that secrete fluids into the ducts of the reproductive system (or into other excretory ducts), and perineal structures that are collectively identified as the external genitalia. In both males and females, the ducts are connected to chambers and passageways that open to the exterior of the body. The reproductive tract is comprised of the structures involved. The female and male reproductive systems are functionally quite different. In adult males, the testes or male gonads, secrete sex hormones called androgens . The testes also produce about a half billion male gametes, called spermatozoa or sperm, each day. During emission, the mature spermatozoa are mixed with the secretions of accessory glands and travel along a lengthy duct system. The mixture created is known as semen. During ejaculation, semen is discharged from the body. In adult females, the ovaries, or female gonads, typically release only one immature gamete, an oocyte , per month. This oocyte travels along one of two short uterine tubes, towards a muscular organ called the uterus. If a sperm reaches the oocyte and initiates the process of fertilization, the oocyte matures into an ovum . A short passageway, the vagina, connects the uterus with the exterior. Ejaculation into the vagina during sexual intercourse introduces semen into the female reproductive tract, and the spermatozoa then ascend through the vagina up towards the uterus. If fertilization occurs, the uterus will enclose and support a developing embryo as it grows into a fetus and prepares for birth. 25.1 Male Reproductive System

©2018

Achieve Page 338

of 368