Chapter 1. Chapter 30: Reproductive System

1.1 Introduction

Welcome to the Interactive Study Guide for Chapter 30: Reproductive System! This Study Guide will help you master your understanding of the chapter's Driving Questions, using interactive Infographics and activities, as well as targeted assessment questions. Click "Next" to get started, or select a Driving Question from the drop-down menu to the right.

DRIVING QUESTIONS

• What is the anatomy of the male and female reproductive tracts?
• What hormones participate in reproduction, and how do they work?
• What are the different types of assisted reproduction, and how do they work?

1.2 Driving Question 1:

Why should you care?

Considering how much of our sense of self is connected to our gender, it's surprising how little many people know about the human reproductive system and their own body. Understanding what the reproductive organs do and where they are is the first step toward taking an active role in your reproductive health. Even if you are not a woman, it important to understand the female reproductive system, if only because it will give you more empathy with 50% of the people you encounter every day.

The male reproductive system is based on the female reproductive system; if no androgen hormones are present in a human with X and Y chromosomes, that human will most likely develop the reproductive features of a female. If you consider this fact, it is easier to understand the male reproductive system. For example, if you consider that the testes and vasa deferentia (pl. of vas deferens) are analogous to the ovaries and oviducts in women, the roundabout route that the vas deferens makes from testis to urethra makes a little more sense. Overall, the reasons for learning about the male reproductive system are the same as for the female reproductive system: you should know how each system works both to control your reproductive health and to be sympathetic with the health concerns of all sexes.

A fertile man produces millions of sperm cells per day. The image of sperm racing each other toward the egg has become a trite joke, but it is grounded in truth. Of the vast number of sperm ejaculated, only the strongest hundred or fewer survive the race to the egg, and only one will fertilize it. Understanding how fertilization works and where it occurs is important knowledge for any responsible adult.

What should you know?

To fully answer this Driving Question, you should be able to:

1. Identify and differentiate between the main parts of the female reproductive system.
2. Identify and differentiate between the main parts of the male reproductive system.
3. Describe the events that lead to fertilization.

Infographic Focus

The Infographics most pertinent to the Driving Question are 30.1 to 30.3 and 30.7.

Identify and differentiate between the main parts of the female reproductive system.

Question 1.1

In the table below, match each organ of the female reproductive system to its function. Then match the organ to its corresponding letter on Infographic 30.1.

Functions	Organs	Location
produces eggs and some sex hormones	E7muCeZVz0tebrHnqqNkShp56Spqm+vrafVqsYE7Kgv0TDGIh0sErjZOvLnsQaRqGg/S7eJGw2xT94Bb	Q4ZGv0YI5qafAGmYpX3wQw==
site of embryo implantation and fetal development	4jyus0tF00qoP1ZFsNuCfU+IBTqvrFf6pqFQAupBLH0W1rcno3lvZynxlIXwwT23FkCZUbd00hQ9o4Ip	6MehWV7MqSUy3pjDrXBsNA==
controls passage of sperm as they travel to the egg	iL6a3Ss9O36cM3bGtFGwPoqHRvuNKal0zRe3D+O1JD9SSjIqLbUK66+US5TyIwqE4A820CRFqiUxqauV	vZa++Dq8H549lKH0Cq8JiQ==
entrance to the female reproductive tract	wo+AedeVGKEW9CHcTskAC7MxiQ92m7CXZc64/2Pbcge2YlkNtM12nVv+4uBUGXDyiUyeIn5roFbGz7RC	+me+h/nUka4M63G+TMw/IA==
site of fertilization and egg release	D/mxWThn4mdRRTPplbcTMCM4itoDllhjOKJKh91/OkaRrNlL4iJkR/YfDwjzfs3RJylo4IlNC7zYsFEf	PkFca+d8rUlqeU4W6lN/vw==

Table

2

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Correct.

Incorrect.

Identify and differentiate between the main parts of the male reproductive system.

Question 1.2

In the table below, match each organ of the male reproductive system to its function. Then match the organ to its corresponding letter on Infographic 30.2.

Functions	Organs	Location
contains paired male sex organs	PQgijYl6j9tkzNeKwj1lTJ+qGAdR44Wtu3u3ydxSqmMaXTyQPDpbW33Qpc/hWubyhj0mCQT/KYrhcjH7O8h4dFNhvou2WrdRR6wYBaZ26bo=	0bnMPaiPvo/hg6nqoBSVSmgL2zA=
carries sperm out of body	aXfGSRaSvBP8pDJCH/tM4ywmzEyoEZnsR0xH3TATobzw9tQ4z/GUG1iUzUE5jVGB7HX7alROTQyCVlUoYGQd4ordhNXIQEKgK6E1VF8Vzgc=	XwgMQ+tRcIvAfGQQFdWj/60AFV4=
carries sperm to the urethra	8lzKSGBfUX5FQI6sJMiaQ1wXI43YOW2vuBxzotffDRaGezd0+y4FoAr7YpWeryVZddjVbA3j20bVx8zyYlGdv2TcI9WTOo9bZrZoFz6BZ2k=	ouOdBxRk0/iEcChcEPlgc+WhO+0=
delivers sperm to the female reproductive system	P2pLJBfsTX1x3iQnX44CGcJxDgZJvi9Wo7XsMbfcOQTo16lEO+vAU7BbMpik4VO7BTcumFkJA+3CrKo7T1xNTEOMWKilH9rKTLyTeAE7k2g=	CHvos/Or8JcDESO+2ULErQBD2No=
stores mature sperm	JMSEk54iwyGOmzVEAA94wfKZ23Paq2vN1Ew75EH1DtDDgMJI3Tz5GH1K/8JoF0C3NiSr9HVUs6fOAczR3nkqJSp3qyfc6qKF6+rN0Yx4bSM=	1SieeOotJwUeOa7QuIc+pLydMds=
ducts that are the site of sperm development	fmI1Bg6W5Mh8/He0I+nB6wk6LOHEvXZKsUByow56l4t1PgPCQnPNXlkCOrccp5FsNXk74mI/VvZJW9gspbVLztEYU2ajBM8oox1wUGdI5fk=	0OSi60KXni8ioT8SVRKDWSswO74=
produces sperm and sex hormones	6i2hRhWwVgTMbCrC3gQzakMkuxQSJ3QCYGNoqq2GvU7Ejzh+pmO+lm/O5BIaY7+6tVBOfJaGQBsyfM/ki2jytGq6RqrC8iTTT+fCWBCy9qc=	DsZEsN5UZx5dyODeNHO8UBuGHfs=

Table

2

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Correct.

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Describe the events that lead to fertilization.

Question 1.3

HLOOkkIO7Ut2qOujOTeoMqFKuIluKmHRWJ+T3E/pT3AIVYiuZzZ2uxTZxBY=

Ovulation is the first step in fertilization; that is, a viable egg must be released from the ovary into the oviduct.

Question 1.4

Assuming that a viable egg is waiting in the oviduct, what path do sperm take to reach it and fertilize it? Fill in the following boxes with the listed terms. Refer to Infographics 30.2 and 30.3 in your text.

A	14O5Lw7ydFPKcKA0VnWBRG/ByFQ+R6yqB2s7/9w9NAoCbwJAVYPhtKJWPHUwG0xjwnQX/4xYBrfCtnJf1z6xgdehq0fPhXDz646dTLgZ/dp08kfVOjt3Fg==
B	yletOSyRX9oWPq0XGjhYjLfCcaUam8XD8yKiMinnGqaLAHPEsLz4Oo9GERJ+NrALwZjqsZFzoLW8QBScye9TZBpD2T2Ouhp1OT+y7fZ8lJlQVHYIhSx9Mw==
C	CouNVKXO/5Ruf3XsR1b5OxDBZEwdvV7SoWCaumHTWJPDJgC8LivpRf1d+PLR/cQSbnPyaS1taLCxVYM27x3ktsGwMYGkWvQQAnTpRiJh6R5aBcf2Kr6Lgw==
D	6roUyiyer9p2sfOoMlmOeMKQ4kknPNze+PK+1Vh8tTkhhA0hb68kx1AG5lgbZM4iBgbHWpYGpdTVC0zRw1kekNj3LN2HlUhDUIsV9kV/3BW0gUz3CQeV/w==
E	ggLioXFj4syykj6+vpcDyNyKP4wkU7eQPRmXZoctndy6tMlLheP4qHWwhMX2A50wutZOi1w3bC5zuDRHOcNgc6Wl0NsnGtTq8V9sy2f1q29MemzKeBkWHA==
F	EGMDa0EoedmVi8toVCuAFRmxdW+Gv2gaeyT9Tn1xksFc9bdmw5mS6n2874gGoXhVeK5ea51pRSz6oFKNE118OElT0NN0oMpYHxyUYuLBJJvJdX+kfNaLiQ==
G	ep9NuUtyXalIQdtqHI27GJktagQ3U/Vd4kCUSi2gqYuhWbM6hopEyPBtfDxzjBEAD6mg84kFemV4eM1LI7nUPWJzwEXCgFnhXWmdREVo+GsYrSJSDet8+A==
H	dOrhaDsOD5FkNqX/U93oFB4WBDdRCEp6I6nnzQu+Mb/o6TEJEJ7AcebGtPJgSGwyHWDiLiUgR8b/Q+PKDYIAtMerAEGKDEUoS1XeSHSZfI5oIvHuwyZ0lQ==

Table

2

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Correct.

Thought question: Why is it important that only one sperm fertilize the egg?

Incorrect.

Thought question: Why is it important that only one sperm fertilize the egg?

1.3 Driving Question 2:

Why should you care?

The menstrual cycle, governed by an array of hormones, causes a predictable cycle of changes in a fertile woman's body. Chances are that you already care about the menstrual cycle, but you may not be aware of all of the changes that happen during it. Understanding the mechanics of the menstrual cycle will help you understand how fertilization occurs as well as how hormonal contraception works.

The fact that hormones support pregnancy (or perhaps prevent it) gave rise to the idea of hormone-based contraception. Imbalances in the hormones that support pregnancy are also the basis for many kinds of infertility.

What should you know?

To fully answer this Driving Question, you should be able to:

1. Describe the functions and sources of the hormones that regulate the menstrual cycle.
2. Explain how the ovaries, hormone levels, and endometrium thickness change throughout the menstrual cycle.
3. Describe the timeline of events leading from ovulation to implantation of an embryo.
4. Explain how hormones regulate pregnancy.
5. Predict how hormone levels could be artificially modified to prevent pregnancy.

Infographic Focus

The Infographics most pertinent to the Driving Question are 30.5 and 30.6 and Table 30.1.

Describe the functions and sources of the hormones that regulate the menstrual cycle.

Question 1.7

Examine Infographic 30.5 and fill in the following chart. (The first entry is an example.)

Hormone	Where is it produced?	What does it do?
Gonadotropin-releasing hormone (GnRH)	Hypothalamus	Stimulates the anterior pituitary to make FSH and LH
FSH	sIAqVrgK5BmL+f/kV1qieFhzZOrgS+9d	/g+YQr5BeUgw4PtcHLVqSa+0sD0=
LH	sIAqVrgK5BmL+f/kV1qieFhzZOrgS+9d	/g+YQr5BeUgw4PtcHLVqSa+0sD0=
Estrogen	sIAqVrgK5BmL+f/kV1qieFhzZOrgS+9d	/g+YQr5BeUgw4PtcHLVqSa+0sD0=
Progesterone	sIAqVrgK5BmL+f/kV1qieFhzZOrgS+9d	/g+YQr5BeUgw4PtcHLVqSa+0sD0=

Table

Hormone	Where is it produced?	What does it do?
Gonadotropin-releasing hormone (GnRH)	Hypothalamus	Stimulates the anterior pituitary to make FSH and LH
FSH	Anterior pituitary	Triggers eggs to mature at the beginning of each monthly cycle; triggers follicle to produce estrogen
LH	Anterior pituitary	A spike of LH causes ovulation.
Estrogen	Ovary (mostly produced by the follicle but some by the corpus luteum); during pregnancy the placenta produces some estrogen.	Triggers pituitary to release LH. Helps thicken the endometrium. Absence of estrogen causes the endometrium to break down and slough off.
Progesterone	Ovary (corpus luteum); during pregnancy, the placenta produces progesterone.	Helps thicken the endometrium. Continuing production of progesterone helps maintain pregnancy by supporting the endometrium. Absence of progesterone causes the endometrium to break down and slough off.

Table

Predict how hormone levels could be artificially modified to prevent pregnancy.

Birth control pills and other hormone-based contraceptives contain estrogen, progesterone, or both. Refer to Infographics 30.5 and 30.6 to answer these questions.

Question 1.17

HTuH9Vnvk8qG6sSdiPgpexJkYtcsvGt0E86ppmWKQA8xpYgUA2VVeX5wlLM6ViF7/FFxW2Rd/yOZH4lHMrZc850DIq2H3Cu7

High levels of progesterone inhibit the hypothalamus from signaling the anterior pituitary to secrete FSH and LH. High levels of estrogen prevent the anterior pituitary from releasing FSH. These two hormones also prevent the thickening of the endometrium (a thin endometrium cannot support a growing embryo) and thicken the mucus at the cervix, adding a physical barrier to sperm.

1.4 Driving Question 3:

Why should you care?

Infertility is a distressing issue for many couples, and diagnosing its source is complicated by the many causes of infertility. Although hopefully you will never have to face infertility, understanding its causes will teach you a great deal about your reproductive health in general.

In vitro fertilization (IVF) and intrauterine insemination (IUI) are the two main forms of assisted reproduction. Both methods have a high failure rate, but the chance of multiple births in successful procedures is much higher than the natural rate. Understanding how the procedures work will help you form informed opinions of ethical issues associated with assisted reproduction technologies.

What should you know?

To fully answer this Driving Question, you should be able to:

1. Describe the causes of infertility in women.
2. Describe the causes of infertility in men.
3. Explain the steps of IVF.
4. Compare and contrast natural fertilization with IVF.
5. Compare and contrast IUI with IVF.
6. Explain how IUI and IVF can both lead to multiple births.

Infographic Focus

The Infographics most pertinent to the Driving Question are 30.4, 30.8, and 30.9.

Compare and contrast natural fertilization with IVF.

Question 1.28

Examine Infographics 30.3 and 30.4 in your text to fill in the chart comparing natural fertilization and IVF.

	Natural Fertilization	IVF
Typical number of eggs released	jr/KPNRFjgvG3GWx	HoYfmrFBlEzq1Bs310SRL1Xtw4Mb+w5I
Where sperm fertilize egg	d3Py3zu2I7olQr79I7SsWO+fckU=	IbXGhOz3Mi/KeR3ErjqsfrSCSLBOoHlVg9/05B2TLUo/H5FY
Number of embryos reaching uterus	dgMMb0RbP4uFpcnnOxog9kCqMfO0o7DFMNCy7HLFcIcQxBzz9Eg0Dw==	HoYfmrFBlEzq1Bs310SRL1Xtw4Mb+w5I

Table

2

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Correct.

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