p274

Figure 9.1 Puberty The body’s endocrine system produces hormones that trigger body changes, including growth spurts, in boys and girls. Figure 9-1 p277

Figure 9.2 The Female Sex Organs and Reproductive Structures Figure 9-2 p279

Figure 9.2 The Female Sex Organs and Reproductive Structures Figure 9-2a p279

Figure 9.2 The Female Sex Organs and Reproductive Structures Figure 9-2b p279

Figure 9.3 Menstrual Cycle (a) In response to the hypothalamus, the pituitary gland releases the gonadotropins FSH and LH. Levels of FSH and LH stimulate the cycle (and in turn are affected by production of estrogen and progesterone). (b) FSH does what its name says—it stimulates follicle development in the ovary. The follicle matures and ruptures, releasing an ovum (egg) into the fallopian tube. (c) The follicle produces estrogen, and the corpus luteum produces estrogen and progesterone. The high level of estrogen at the middle of the cycle produces a surge of LH, which triggers ovulation. (d) Estrogen and progesterone stimulate the endometrium, which becomes thicker and prepares to receive an implanted, fertilized egg. If a fertilized egg is deposited in the uterus, pregnancy begins. If the egg is not fertilized, progesterone production decreases, and the endometrium is shed (menstruation). At this point, both estrogen and progesterone levels have dropped, so the pituitary responds by producing FSH, and the cycle begins again. Figure 9-3 p281

Figure 9.4 Male Sex Organs and Reproductive Structures Figure 9-4 p283

Figure 9.4 Male Sex Organs and Reproductive Structures Figure 9-4a p283

Figure 9.4 Male Sex Organs and Reproductive Structures Figure 9-4b p283

The key to a healthy, happy sexual relationship is open, honest communication—even when you and your partner have different points of view. p285

During adolescence, teens explore different social and intimate relationships as they begin to develop a sexual identity. p287

In a loving, committed relationship, every form of physical contact can serve as an intimate form of expressing deep emotion. p290

Close-couple homosexual relationships are similar to stable heterosexual relationships. p292

Couples can find many ways to express their affection for and delight in each other. p296

Figure 9.5 A Cross-Sectional View of Sexual Intercourse Sperm are formed in each of the testes and stored in the epididymis. When a man ejaculates, sperm carried in semen travel up the vas deferens. (The prostate gland and seminal vesicles contribute components of the semen.) The semen is expelled from the penis through the urethra and deposited in the vagina, near the cervix. During sexual excitement and orgasm in a woman, the upper end of the vagina enlarges and the uterus elevates. After orgasm, these organs return to their normal states, and the cervix descends into the pool of semen. Figure 9-5 p297

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6a p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6a (1) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6a (2) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6a (3) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6a (4) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6b p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6b (1) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6b (2) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6b (3) p298

Figure 9.6 Human Sexual Response The four stages of sexual response are excitement, plateau, orgasm, and resolution. Figure 9-6b (4) p298

Sexual problems can be difficult for partners to talk about, but lack of communication can create tension and increase anxiety. p301

Sex sells. Topless bars and strip clubs are among the businesses that cater to those who enjoy sexual stimulation outside a loving relationship. p305