Bio 322 Human Anatomy Objectives for the laboratory exercise Female Reproductive System

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1 Bio 322 Human Anatomy Objectives for the laboratory exercise Female Reproductive System Required reading before beginning this lab: Saladin, KS: Human Anatomy 5 th ed (2017) Chapter 26 For this lab you will use parts of Exercises #29 in your Wise lab manual. Please be sure to read that before coming to lab or you will not be able to finish within the scheduled lab time. Introduction: The reproductive system is somewhat unique as it is the only system in which the two sexes have different organs. Ovaries and testicles are the only organs in which cell division occurs by meiosis to produce haploid oocytes (eggs) and sperm (collectively called gametes). When the two haploid gametes fuse at fertilization, the resulting zygote is again diploid with 46 chromosomes arranged as 23 pairs. Producing the oocytes, of course, is only one of many functions of the female reproductive system. After ejaculation by he male, the sperm must reach the proper location to fertilize the oocyte; the resulting zygote must reach the uterus and implant itself there; pregnancy must be maintained for nine months; and childbirth must successfully occur. After birth, the mammary glands in the breast produce the milk to nourish the infant. The female reproductive system is also unique for its highly cyclical function. As the ovaries produce oocytes they also secrete estrogen to stimulate changes in the uterus and other organs in preparation for fertilization and pregnancy, After the ovulation of one or two oocytes, the ovaries secrete progesterone to maintain and increase those changes. Thus, the cyclical changes in many different organs of the female reproductive system are closely linked and coordinated. Before you begin this exercise, be sure you have a moderately good understanding of how the male and female reproductive systems work: formation and transport of sperm and oocytes, sexual arousal and intercourse, ejaculation, the menstrual and ovarian cycles, pregnancy, and childbirth.

2 Objectives: 1) Complete Exercise #29 in your Wise lab manual except for Stages of Development and Cat Anatomy at the end. When you have completed this lab exercise: a) On the torso model with female genitalia in place, you should be able to identify the ovaries, oviducts (Fallopian tubes), and superior surface of the uterus. Note that the oviducts extend laterally on each side from the uterus. Note that the distal end of each oviduct surrounds, but does not directly connect with, the ovary on that side. Note the finger-like fimbria on the distal end of each oviduct. Remove the genitalia and examine them in midsagittal section. You should be able to identify the lumen of the uterus, the vagina, the labia minora ( small lips ), the labia majora ( large lips ), and the clitoris. Note the position of the uterus posterior and superior to the urinary bladder, and anterior to the rectum. b) On isolated models of the female reproductive system, you should be able to identify the ovaries, oviducts (Fallopian tubes), uterus, vagina, labia minora, labia majora, and clitoris. Again, note that the distal end of each oviduct surrounds, but does not directly connect with, the ovary on that side. Again, note the finger-like fimbria on the distal end of each oviduct. c) On Figure 29.5 in your Wise lab manual you should be able to identify the isthmus, ampulla, infundibulum, and fimbria of the oviduct. d) Separate the two halves of the model and examine them in midsagittal section. You should again note the position of the uterus posterior and superior to the urinary bladder, and anterior to the rectum. You should again be able to identify the lumen of the uterus, the vagina, the labia minora, the labia majora, and the clitoris in this midsagittal view.. e) Although it doesn t show well on the models, realize from Figure 29.1 in your Wise lab manual that the superior surface of the uterus is covered by a layer of the peritoneum which lines that cavity. The peritoneum also surrounds the oviduct on each side.

of the vagina. From the models and Figure 29.7 of your Wise lab manual, note how the inferior end of the vagina opens exteriorly into the space between the two labia minora, called the vestibule.

3 f) On the models and on Figure 29.1 of your Wise lab manual, note how the inferior end of the uterus called the cervix, extends into the superior part of the vagina, and that the lumen of the cervix of the uterus opens into the lumen of the vagina. From the models and Figure 29.7 of your Wise lab manual, note how the inferior end of the vagina opens exteriorly into the space between the two labia minora, called the vestibule. Note that the urethra also opens into the vestibule, but that the anus does not. 2) Examine Figures 29.8 and 29.9 in your Wise lab manual, showing the anatomy of the breast. a) Identify the nipple and surrounding areola on the anterior surface. b) In the sagittal section shown in Figure 29.9, identify the mammary gland tissue, the lactiferous ducts, and lactiferous sinuses. Note that much of the breast is composed of adipose tissue rather than mammary gland tissue. 3) Histology of the Female Reproductive System a) Examine slide #40 of the ovary under low power. This slide is not from a human - it is from an animal that gives birth to many young at a time since it shows many follicles developing simultaneously. Identify its cortex, medulla, and tunica albuginea. Identify follicles in different stages of development, including large fluid-filled mature follicles. Identify a corpus luteum, in which cells have filled in the central region of the follicle. b) Examine the model representing half of an ovary with different stages of development of the follicles. At the middle bottom is a mature or vesicular follicle that is in the process of ovulation: rupturing to release its egg, or oocyte (sometimes, although not quite correctly, called the ovum). To the left of the mature follicle is a large, yellow, scalloped structure, a corpus luteum ( yellow body ). It formed from a previously ovulated mature follicle. Between the mature follicle and corpus luteum is one of three corpus albicans ( white body ). These are

4 the remnant scars of previous corpora lutea (that s the plural of corpus luteum ). To the left of the mature follicle are three medium-sized, immature, secondary follicles that may someday become mature follicles. c) Examine slide #19 of the oviduct or Fallopian tube under low power. Note this is a tube with very a very thick muscularis, within which many blood vessels are easily identified. Notice how the mucosa is thrown into very long folds extending far into the lumen. Under high power, examine the mucosa of the uterine tube. The epithelium varies from simple squamous to simple columnar in form, with the latter representing more active regions of the organ. You may or may not be able to identify brush-like projections extending from the apical surface of the columnar cells - these are the cilia which help propel sperm toward the oocyte and later help propel the oocyte or developing embryo toward the uterus. Identify the connective tissue lamina propria within the folds. 4) This will require you to take off most of your clothing, so you should obviously do it at home. a) If you are female (or if you have a willing female partner) identify the location of the bladder, urethra, ovaries, oviducts, uterus, and vagina. Use a pen (preferably water soluble) to draw these structures on the skin. b) On yourself (or a willing female partner) identify the labia majora, labia minora, vestibule, clitoris, urethral orifice, and vaginal orifice you may need to use a mirror to do this on yourself. Notice that pubic hair grows on the lateral surfaces of the labia majora but not on their medial surface or on the labia minora. Use a finger to feel the transition from the keratinized (dry) form of stratified squamous epithelium on the skin to the nonkeratinized (wet) form as you enter the vagina.

5 Review: After you have completed this lab exercise, be sure you can answer the questions at the end of Exercise #29 in your Wise lab manual, but do this verbally with your lab partners rather than in written form. The purpose of doing this should not be to write down the correct answer, but rather to be sure that everyone in your lab group understands the information presented in the exercise and to identify any areas which you still do not understand. Remember: one of the best ways to learn new information and to be sure you understand it is to discuss it with another person. If you can t easily answer one of the questions, go back to your Saladin textbook and re-read the relevant section(s), It is also an excellent idea for members of a lab group to set up small quizzes for each other. Ask each other to identify structures on diagrams and models. Ask each other to explain the functions of those structures. Here are some additional questions and discussions which may help you understand the female reproductive system. Remember these are for discussion, not writing. That s the best way to be sure your brain can explain what you have learned. Explain to other members of your lab group the pathway that sperm will follow after ejaculation into the vagina to where fertilization will occur, the pathway that the resulting embryo will follow to the uterus, and how it will embed itself within the endometrium. Explain to the other members of your lab group the sequence of follicular development in the ovary, from a primordial follicle, through ovulation and the formation of a corpus luteum, to the corpus albicans. Include hormones from the pituitary gland that stimulate this process and hormones that are produced by the follicle and corpus luteum, including the functions of the latter. The early stages of follicle development, before ovulation, occur under the stimulation of which hormone from the anterior pituitary gland? During which part of the menstrual cycle is this occurring? The conversion of a follicle to a corpus luteum, after ovulation, occurs under the stimulation of which hormone from the anterior pituitary gland? During which part of the menstrual cycle is this occurring? If the oocyte is fertilized by sperm, where (which part of which organ) in the female reproductive system will this occur? During which part of the menstrual cycle is this most likely to occur?

The Reproductive System

Biology 212: Anatomy and Physiology II The Reproductive System References: Saladin, KS: Anatomy and Physiology, The Unity of Form and Function 8 th (2018). Required reading before beginning this lab: Chapters