Chapter 32: The Reproductive System
LEARNING OUTCOMES
After completing Chapter 32, students should be able to:
32.1 Summarize the organs of the male reproductive system including the locations, structures, and functions of each.
32.2 Describe the causes, signs and symptoms, and treatment of various disorders of the male reproductive system.
32.3 Summarize the organs of the female reproductive system including the locations, structures, and functions of each.
32.4 Describe the causes, signs and symptoms, and treatment of various disorders of the female reproductive system.
32.5 Explain the process of pregnancy, including fertilization, the prenatal period, and fetal circulation.
32.6 Describe the birth process, including the postnatal period.
32.7 Compare several birth control methods and their effectiveness.
32.8 Explain the causes of and treatments for infertility.
32.9 Describe the causes, signs and symptoms, and treatments of the most common sexually transmitted infections.
Lecture Outline
Learning Outcome 32.1: Summarize the organs of the male reproductive system including the locations, structures, and functions of each.
•Lecture Topics
•Start the discussion by stating that when they function together perfectly, the male and female reproductive systems produce offspring. (Refer to PowerPoint Slide 4.)
•Emphasize to students that for reproduction to take place, the gonads, or sex organs, which are the ovaries in females and the testes in males, along with their accessory organs, must function correctly. Note that in females, the ovaries produce the hormones estrogen and progesterone as well as ova; in males, the testes produce the hormone testosterone as well as sperm.
•Explain that the two testicles are held in the scrotum, which keeps them the necessary one degree lower in temperature than the rest of the body, and that each is divided into lobules containing seminiferous tubules filled with spermatogenic cells, which will become sperm. (Refer to PowerPoint Slides 4 – 6.)
•Review the process of meiosis (Refer to Figures 32-2 and 32-3.) Point out that in meiosis, each primary spermatocyte divides to make two secondary spermatocytes, and then each secondary spermatocyte divides to make two spermatids. Therefore, from one primary spermatocyte, four spermatids are formed. Explain that spermatids develop flagella to become mature sperm cells containing only 23 chromosomes. (Refer to PowerPoint Slides 7 – 8.)
•Discussion Points
•Ask your students to name and discuss the male external genitalia. (The scrotum, which contains the testes, and the penis.) (Refer to PowerPoint Slide 11.)
•After the functions of the testes have been discussed, ask your students: What is the function of the penis? (The penis delivers sperm into the female reproductive tract. It also functions as the urethra for the urinary system.)
•Explain where testosterone is produced. (In the interstitial cells between the seminiferous tubules.) Discuss the fact that although sperm are produced in the seminiferous tubules, they mature in the epididymis.
•Point out that in addition to the testes, the male reproductive system includes internal accessory organs. Ask students to name these organs (epididymis, vans deferens, seminal vesicles, the prostate gland, bulbourethral glands) and discuss with the class these accessory organs and their functions. Make sure to explain the vas deferens, which is connected to the epididymis, and how it carries the sperm from the epididymis to the urethra in the pelvic cavity. Ask a volunteer to explain the term vasectomy. (Literally, to cut out the vas; a vasectomy is the male sterilization procedure.) (Refer to PowerPoint Slides 9 – 10.)
•Discuss the prostate gland, explaining that it surrounds the base of the urethra and secretes an alkaline fluid to protect the sperm in the more acidic female vagina. Ask the class to name the fluid mixture of semen and the percentages of the fluids that contain sperm. (Semen is 60% seminal fluid and 40% prostatic fluid.)
•Brainstorm with the class to name some of the male secondary sex characteristics that become evident during puberty. (Chest hair, facial hair, thickening and strengthening of bones and muscles, pubic hair, deepening of the voice.) Explain that these characteristics result from the surge of testosterone during puberty. (Refer to PowerPoint Slides 12 – 13.)
•Learning Activities
•Following a discussion on the three parts of a mature sperm (the head, midpiece, and tail), ask students to explain the function of each of these parts in a brief report with illustrations. (The head holds a nucleus with 23 chromosomes and is covered by an enzyme-filled sac called an acrosome, which helps the sperm penetrate the protective shell of the egg. The midpiece contains mitochondria, which provide energy for the sperm to move. The tail is the flagellum that propels the sperm forward.) (Refer to Figure 32-3 and PowerPoint Slide 8.)
•Begin a discussion of male reproductive hormones by stating that the hypothalamus releases a hormone called gonadotropin-releasing hormone (GnRH) at puberty, which stimulates the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Ask students to research the functions of FSH and LH (spermatogenesis and testosterone production, respectively) and discuss their results in small groups. (Refer to PowerPoint Slide 13.)
Learning Outcome 32.2: Describe the causes, signs and symptoms, and treatment of various disorders of the male reproductive system.
•Lecture Topics
•Review with the class the causes, signs and symptoms, and treatments for the diseases and disorders of the male reproductive system. Answer questions and elaborate on the information as needed to encourage student understanding of the material. (Refer to PowerPoint Slide 15 – 16.)
•Discussion Points
•Discuss the types of cancers that may affect the male reproductive organs, including prostate and testicular cancer. Review the causes, signs and symptoms, and treatment options for these cancers.
•Learning Activities
•Invite a urologist, an RN, or a medical assistant employed in a urology office to speak to the class about some of the common disorders affecting the male reproductive system, including updates on the latest treatment options. Alternatively, ask a prostate or testicular cancer survivor to speak of his diagnosis and treatment experience. Make sure the class prepares appropriate questions for the speaker.
Learning Outcome 32.3: Summarize the organs of the female reproductive system including the locations, structures, and functions of each.
•Lecture Topics
•Teach your students that the ovaries are considered the primary female sex organs because they produce the female sex cells, called ova, as well as producing estrogen and progesterone. (Refer to Figures 32-4 and 32-5 and PowerPoint Slides 18 – 23.)
•Review the external female genitalia (vulva). Discuss what organs compose the female genitalia (mons pubis, the labia majora and labia minora, clitoris, urinary meatus, the vaginal introitus, Bartholin's glands, and the perineum.) (Refer to Figure 32-6 and PowerPoint Slides 24 - 25.)
•Explain that the labia majora consist of adipose tissue and skin that anteriorly forms the mons pubis. Note that the labia minora are highly vascular folds that form a protective hood around the clitoris.
•Make sure your students understand that the area within the labia minora is referred to as the vestibule, and its Bartholin's glands secrete mucus during sexual arousal as a lubricant for intercourse. (Refer to PowerPoint Slides 26 – 27.)
•Remind students that, beginning in puberty, the anterior pituitary gland releases two hormones (FSH and LH). Note the effects these hormones have on the female reproductive system? (The production of estrogen and progesterone, and maturation of the ovarian follicles, with eventual release of the mature ovum during the process of ovulation.)
•To begin a discussion about the female re-productive cycle, ask: What is the common name for the female reproductive cycle? (Menstrual cycle.) Ask: What are the terms used to describe the start and cessation of this cycle? (Menarche and menopause.) (Refer to PowerPoint Slides 28 – 29.)
•Make sure that students have a basic understanding of the changes that take place in one reproductive or menstrual cycle as the woman ages. (Refer to Figure 32-7.)
•Discussion Points
•Begin the discussion of the female reproductive system by asking students the following question: If ovaries are the female counterpart to the testicles, what do they produce? (Ova, or eggs, and the hormones estrogen and progesterone.) Explain that the process of egg or ovum formation is known as oogenesis and that ovulation is the release of the mature ovum from the ovary.
•Ask members of the class to name the internal accessory organs related to female reproduction (fallopian tubes, uterus, vagina.) Explain that the fimbriae of the fallopian tubes, sometimes called uterine ducts or oviducts, "catch" the ovum after ovulation and its cilia, combined with the muscular peristalsis of the tube, sweep the ovum toward the uterus to await fertilization by the sperm.
•Explain the following structures: the uterus is the muscular home for the fertilized ovum, the upper rounded portion of the uterus is called the fundus, and the midsection is the body, and its neck is known as the cervix.
•Point out that the vagina is the muscular, tube-like organ that extends from the uterus to the outside. Students should also be made aware that the uterus consists of three layers: the outer layer, or perimetrium; the muscular middle layer, or myometrium; and the inner layer, or endometrium.
•Learning Activities
•Ask students to list the female secondary sex characteristics, and write them on the board. (Breast development, axillary and pubic hair, increased skin vascularization, and increased fat deposits in the breasts, thighs, and hips.) Have the students devise a time-line for the development of the female reproductive system and compare it to the development of the male reproductive system.
Learning Outcome 32.4:Describe the causes, signs and symptoms, and treatment of various disorders of the female reproductive system.
•Lecture Topics
•Teach your students that according to the American Cancer Society, breast cancer is the second leading cause of cancer deaths in women after lung cancer. Point out that depending on tumor size and how far cancer cells have spread, breast cancer is classified in stages from 0 to 4, with stage 4 cancer being the most serious.
•Discussion Points
•Discuss the causes, signs and symptoms, and treatment options for the following disorders:
•Breast cancer
•Cervical cancer
•Cervicitis
•Dysmenorrhea
•Endometriosis
•Fibrocystic breast disease
•Fibroids
•Ovarian cancer
•Premenstrual syndrome (PMS)
•Uterine cancer
•Vaginitis (Refer to PowerPoint Slides 31 – 33.)
•Learning Activities
•Divide the class into groups of two to three students and have each group choose, or be assigned, a disease or disorder discussed in the text. Each group should research their disorder, defining the causes, signs and symptoms, preventative measures, if any, and available treatments. Have groups present their findings to the class. Review, clarify, and expand on information as needed.
•Invite a gynecologist, an RN, or a medical assistant employed in a gynecology office to speak to the class regarding some of the common disorders affecting the female reproductive system, including updates on the latest treatment options. Make sure the class prepares appropriate questions for the speaker.
Learning Outcome 32.5:Explain the process of pregnancy, including fertilization, the prenatal period, and fetal circulation.
•Lecture Topics
•Teach your students that pregnancy is defined as the condition of having a developing offspring in the uterus. Point out that pregnancy results when a sperm cell unites with an ovum in a process called fertilization. (Refer to Figure 32-8 and PowerPoint Slide 35.)
•Review the hormone that is tested for in order to confirm pregnancy. (HCG, human chorionic gonadotropin.) Explain that this hormone maintains the corpus luteum so that estrogen and progesterone are secreted by the ovary and placenta. Point out that the corpus luteum also secretes relaxin so that the uterus does not contract during the pregnancy, and the placenta produces lactogen to stimulate enlargement of the mammary glands in preparation for nursing.
•Explain that when progesterone levels drop at the end of the pregnancy, prostaglandins stimulate uterine contractions, and the posterior pituitary gland releases oxytocin to stimulate the strong uterine contractions of labor, until birth occurs and the placenta is expelled.
•Discussion Points
•Ask the class to name the terms that mean the uniting of the sperm and ovum. (Fertilization, conception, pregnancy.) Students may find it interesting that although the human sperm may live for 48 to 72 hours after ejaculation, the ovum lives only 24 hours after ovulation.
•Discuss how the 23 chromosomes of the sperm join with the 23 chromosomes of the ovum during conception, creating the 46 chromosomes of the zygote. Note that the cells are called a zygote until week two; it is referred to as an embryo from weeks two to eight; from weeks nine through delivery, it is referred to as a fetus. (Refer to PowerPoint Slides 36 – 38.)
•Ask students to name the organ that allows nutrients and oxygen to pass from the mother to the embryo or fetus (placenta). Review the purpose of the amnion (protection of the unborn embryo or fetus). (Refer to Figure 32-8 for the early stages of fetal development and Figure 32-9 for primary germ layers and membranes associated with an embryo.)
•Initiate a discussion on fetal circulation. Explain that because the mother's body and blood provide nutrients and oxygen to the fetus, its circulatory system contains several important differences when compared to normal circulation. Write these on the board as you explain them. The first difference is the foramen ovale, which is the hole between the right and left atria. Because the fetal right ventricle does not have to push blood to the lungs for oxygenation, most of the blood goes directly to the left atria, although some does get directed to the pulmonary trunk. The second difference is the ductus arteriosus, which is an opening between the pulmonary trunk and the aorta. The last difference is the ductus venosus, which allows blood to bypass the liver, because the mother's circulatory system takes care of cleansing fetal blood. Remind the class that all these openings close prior to or soon after birth. (Refer to Figure 32-10: Fetal Circulation and PowerPoint Slides 39 – 41.)
•Learning Activities
•Discuss the three distinct stages of pregnancy known as trimesters. Have your students research these trimesters and write a report on what occurs in each.
•Invite an obstetrician or nurse midwife to speak to the class about the process of labor and delivery. Be sure the speaker explains about the lie and presentation of the fetus and common problems that may occur during the delivery process.
Learning Outcome 32.6: Describe the birth process, including the postnatal period.
•Lecture Topics
•Remind your students that the birth process, which begins when progesterone levels fall, ends pregnancy. Point out that the birth process itself occurs in three stages after the fetus settles into position in the mother’s pelvis. (Refer to Figure 32-11 and PowerPoint Slides 43 – 45.)
•Discussion Points
•Review the three stages of the birth process (dilation, expulsion, and the placental stage). Ask volunteers to define the following terms related to pregnancy and birth, writing the correct answers on the board: prenatal period (before birth), postnatal period (after birth), neonatal period (new birth, the first four weeks), neonate (newborn to the age of 4 weeks).
•Make sure students understand what is meant by breach (a fetus who is not in the head-down position for birth; a position other than head-down.).
•Learning Activities
•Divide the class into small groups to research and discuss the advantages and disadvantages of breastfeeding versus bottle-feeding an infant. Assign a group leader for each group to record the discussion and share the results with the rest of the class.
Learning Outcome 32.7: Compare several birth control methods and their effectiveness.
•Lecture Topics
• Teach your students that birth control methods, also referred to as contraception, reduce the risk of pregnancy. (Refer to Figure 32-12.).
•Discussion Points
•Discuss the most commonly used birth control methods including:
•Coitus interruptus
•Rhythm method
•Mechanical barriers
•Chemical barriers
•Oral, injectable, and insertable contraceptives
•Contraceptive implants
•Transdermal contraceptives
•Intrauterine devices
•Surgical methods (Refer to Figure 32-12 and 32-13 and PowerPoint Slides 47 – 49.)
•Learning Activities
•Obtain and bring into the class various forms of contraceptive devices. Have students take turns picking a device and explaining how to use it to the class. Poll the class to see what would be their preferred method of contraception if using one.