39–3 The Male Reproductive System Sexual Development: 2 parts Section Outline Section 39-3 39–3 The Male Reproductive System Sexual Development: 2 parts 1. For first 6 weeks in utero, embryo is identical 2. At 7th week, gonads in XY make testosterone—reproductive organs made 3. Gonads in XX make estrogen—reproductive organs made

1. LH & FSH stimulate testes to make testosterone (hormone) Section Outline Section 39-3 B. 2nd part at puberty-hypothalamus signals pituitary gland to make LH & FSH 1. LH & FSH stimulate testes to make testosterone (hormone) 2. Testosterone responsible for making sperm AND secondary sex characteristics (deeper voice, body hair, etc). 3. Sperm production goes on until death

C. The Male Reproductive System. Purpose is to make & deliver sperm Section Outline Section 39-3 C. The Male Reproductive System. Purpose is to make & deliver sperm 1. Sperm Development Made in seminiferous tubules Stored in epididymis When ejaculated, sperm travel through vas deferens and is dumped into urethra

2. Seminal vesicle & prostate add fluids to protect & nourish sperm Section Outline Section 39-3 2. Seminal vesicle & prostate add fluids to protect & nourish sperm Fluid + sperm = semen 3. Sperm Release A. Smooth muscles lining glands contract to eject semen

Figure 39–12 The Male Reproductive System Section 39-3

Section Outline 39–3 The Male Reproductive System Sexual Development: 2 parts For first 6 weeks in utero, embryo is identical At 7th week, gonads in XY make testosterone—reproductive organs made Gonads in XX make estrogen—reproductive organs made 2nd part at puberty-hypothalamus signals pituitary gland to make LH & FSH LH & FSH stimulate testes to make sperm The Male Reproductive System Purpose is to make & deliver sperm Sperm Development Made in seminiferous tubules Stored in epididymis When ejaculated, sperm travel through vas deferens and is dumped into urethra Seminal vesicle & prostate add fluids to protect & nourish sperm Fluid + sperm = semen Sperm Release Smooth muscles lining glands contract to eject semen C. The Female Reproductive System 1. Egg Development 2. Egg Release D. The Menstrual Cycle 1. Follicular Phase 2. Ovulation 3. Luteal Phase 4. Menstruation E. Sexually Transmitted Diseases

The Menstrual Cycle Section 39-3

Figure 39–14 The Female Reproductive System Section 39-3

Interest Grabber More Than One Section 39-4 More Than One Fertilization is the fusion of a sperm and an egg to form a zygote, the single cell from which all cells of the human body are derived. When an egg is fertilized, the remarkable process of human development begins. 1. If two eggs are released during ovulation, each can be fertilized by a sperm. What do you think would be the result? Explain your answer. 2. If one zygote splits into two, each can continue development on its own. What do you think would be the result? Explain your answer. 3. Triplets are three babies born at the same time. Describe three ways that triplets could develop.

Section Outline 39–4 Fertilization and Development A. Fertilization B. Early Development 1. Implantation 2. Gastrulation 3. Neurulation 4. Extraembryonic Membranes C. Control of Development D. Later Development E. Childbirth F. Multiple Births G. Early Years 1. Infancy 2. Childhood 3. Adolescence H. Adulthood

Fertilization and Implantation Section 39-4 Uterine wall Blastocyst Morula 4 cells 2 cells Zygote Ovary Fallopian tube Day 3 Day 2 Day 1 Day 4 Fertilization Day 0 Day 7 Implantation of blastocyst Egg released by ovary

Figure 39–22 The Placenta Section 39-4

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Go Online Interactive test For links on the endocrine system, go to www.SciLinks.org and enter the Web Code as follows: cbn-0391. For links on glands, go to www.SciLinks.org and enter the Web Code as follows: cbn-0392. For links on gametes, go to www.SciLinks.org and enter the Web Code as follows: cbn-0393. For links on human growth and development, go to www.SciLinks.org and enter the Web Code as follows: cbn-0394. Internet

Interest Grabber Answers 1. Describe a situation in which the body could use the endocrine system to deliver a “slow” message. Slow messages include those about growth, water balance, and the proper metabolism of substances. 2. Describe a situation in which the body could use the nervous system to deliver a “fast” message. Fast messages include those about sensing and responding. 3. Develop an analogy that illustrates this difference between these two systems. Possible answer: Slow messaging: mail delivered by the mail carrier. Fast messaging: e-mail. Section 1 Answers

Interest Grabber Answers 1. When you are frightened, it triggers the “fight-or-flight” response. Describe the changes that took place in your body the last time you were in a scary situation. Students may describe an increase in breathing and heart rate, sweaty palms, and so on. 2. Which body structures do you think become readied for this “fight-or-flight” response? Why do you think this happens to these structures? Heart, muscles, lungs. In order to provide the muscles with more oxygen. 3. Which body structures do you think are slowed down during this “fight-or-flight” response? Why do you think this happens? Answers may include organs of the digestive and excretory systems. These structures are not needed for this action. Section 2 Answers

Interest Grabber Answers 1. How does an eight-year-old male’s voice compare to that of an adult male? How does an eight-year-old female’s voice compare to that of an adult female? The boy’s voice is much higher. The girl’s voice is not much different from the adult female’s voice. 2. What do you think causes the differences in the voices? Explain your answer. An increase in certain hormones causes the change. This occurs as the boy matures into an adult male. 3. Another change that occurs between 9 and 15 is a growth spurt, which is a rapid increase in height. Do you think growth spurts occur earlier in males or in females? Explain your answer. Sample answer: In females; in 6th grade, many girls were taller than boys, but by 9th grade, more boys were taller than girls. Section 3 Answers

Interest Grabber Answers 1. If two eggs are released during ovulation, each can be fertilized by a sperm. What do you think would be the result? Explain your answer. Fraternal (not genetically identical) twins would result, since they would develop from two eggs fertilized by two sperm. 2. If one zygote splits into two, each can continue development on its own. What do you think would be the result? Explain your answer. Identical (genetically identical) twins would result, since they would develop from one egg fertilized by one sperm. 3. Triplets are three babies born at the same time. Describe three ways that triplets could develop. a. A zygote could split into three (identical triplets). b. Triplets could also result from two separate eggs being fertilized, with one of the zygotes splitting into two. c. Three separate eggs, each fertilized by a different sperm. Section 4 Answers

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