Chap.15 Animal reproduction8 Fig Long-term bonds are built between the sexes of a variety of animals. 長期的親密關係
Chap.15 Animal reproduction9 Fig The male reproductive system 尿道 膀胱 前列腺 肛門 海綿組織 恥骨 膀胱 海綿組織
Chap.15 Animal reproduction10 Fig the female reproductive system 輸卵管壁上的纖毛 輸卵管 子宮 陰道 尿道 大陰唇 陰蒂
Chap.15 Animal reproduction11 Fig The relationship of female reproductive hormones and the events in the ovary and uterus during a 28-day menstrual cycle. 腦下垂體 體溫 黃體
Chap.15 Animal reproduction12 The human sexual response u The physical prerequisites of copulation are simply an erect penis and a lubricated vagina. u These conditions are usually achieved during the course of precopulatory sexual behavior or foreplay.
Chap.15 Animal reproduction13 Penis erected u The human penis is supplied with a great number of blood vessels, some of which open into large blood chambers. u Parallel veins and arteries service the penis, and during sexual arousal, the arteries relax and enlarge, allowing an increased blood flow into the spongy tissue of the penis. u The veins, however are compressed as the spongy tissue fills with blood.
Chap.15 Animal reproduction14 Female response u In women, foreplay also causes blood to accumulate in certain structures. u One result of this is the vaginal walls seep fluid that serves as a lubricating substance. u The lubricating may begin, however, well before she is emotionally ready for intercourse.
Chap.15 Animal reproduction15 As foreplay continues u With more extensive foreplay, the labia minora and clitoris may enlarge and redden as blood rushes to those areas. u About this time, the nipples may also harden and enlarge. u As foreplay continues, the shoulders and chest may mottle and the breasts may enlarge and grow more sensitive.
Chap.15 Animal reproduction16 copulation u Copulation involves the insertion of the erect penis into the vagina. u After a few or many pelvic thrusts, the male ejaculates. u The semen usually ejects from the penis with considerable force in the first few contractions. u It is in this first fluid that the greater part of the spem is concentrated. (Fig. 15.8)
Chap.15 Animal reproduction17 Fig Human sperm. Each ejaculation normally contains 200 to 800 million sperm.
Chap.15 Animal reproduction18 Fig A human egg descending toward the uterus.
Chap.15 Animal reproduction19 Fig The sperm have reached the egg and have surrounded it. However, only one sperm will enter into fertilization.
Chap.15 Animal reproduction20 Orgasm u Orgasm, which normally accompanies ejaculation, is part of the final stage of the copulatory act. u The accompanying physiological changes include an increase in blood pressure and a quickened pulse. u The postclimactic period is marked by a feeling of relaxation. The blood vessels return to their original state, and the penis again becomes flaccid.( 癱軟 )
Chap.15 Animal reproduction21 Essay 15.2 Why your children will not look exactly alike. The odds of you having children with identical genetic constituents have been calculated at about 1 in 14 trillion.
Chap.15 Animal reproduction22 Sex and Society u Among chimpanzees, a pink lady may copulate with every adult male in the group, as well as some adolescents. u Since only one male is needed to impregnate the female, the act of copulation is believed to a means of developing social bonds within the group.
Chap.15 Animal reproduction23Contraception u Table 15.3 summary of contraceptive methods. u The rhythm method 男女合作 失敗率 24/100 u Coitus interrupts 男生 失敗率 30/100 u The condom 男生 失敗率 7-30/100 u Diaphragm 女生 失敗率 2-20/100 u The cervical cap 女生 失敗率 2-20/100 u spermicides 女生 失敗率 10-25/100 u IUD (Intrauterine device) 失敗率 1/100 u The birth control pill 失敗率 1-3/100
Chap.15 Animal reproduction24 Fig An advertisement encouraging the use of condoms as protection against sexually transmitted disease.
Chap.15 Animal reproduction25 Fig The diaphragm and cervical cap both operate on the same principle, blocking the cervix.
Chap.15 Animal reproduction26 Fig the simple procedure of a vasectomy.
Chap.15 Animal reproduction27 Fig Tubal lifation is a means of sterlization in women.
Chap.15 Animal reproduction28 Fig People feel strongly about the rights of women to decide whether to have children. Some are very opposed to the right to end a pregnancy with an abortion.