Chapter 22 Reproduction in Humans Summary Bk3 Ch.22 Reproduction in Humans/1 Table 1: Reproductive systems in humans (Section 22.1) Male reproductive system (Fig. 22.2) Female reproductive system (Fig. 22.5) Structure Testes A pair of sex organs Lie outside the abdomen Made up of many highly coiled sperm-producing tubules (seminiferous tubules) (Fig. 22.3) Description Produce sperms and male sex hormones Scrota A pair of sacs of muscles and skin Enclose the testes Epididymis Vas deferens Urethra Penis A highly coiled tube lying beside the testis A muscular tube responsible for the transfer of sperms out of the testis Join the urethra Responsible for discharging urine and sperm-containing semen out of the body Runs through the penis Seminal vesicle A sex gland Prostate gland Made up of erectile tissues and numerous blood spaces A sex gland Cowper s gland A sex gland Ovaries Oviduct A pair of sex organs Small oval bodies held in the abdominal cavity by ligaments A long, narrow, ciliated muscular tube at each side of the abdomen Funnel-shaped opening of oviduct close to each ovary Stores sperms temporarily Secrete seminal fluid which nourishes and activates sperms (seminal fluid and sperms together form the semen) Produce ova and female sex hormones Helps to move the ovum along the duct Receives ovum from the ovary during ovulation Uterus A wide central muscular sac Provides protection and a steady internal environment for the embryo to develop Cervix A narrow opening at the base of uterus Guarded by a ring of muscle 1
Structure Vagina A muscular tube Runs behind the urethra Description Bk3 Ch.22 Reproduction in Humans/2 Receives the penis during copulation Acts as the birth canal Table 2: Sperm (Section 22.1) Characteristics of a sperm (Fig. 22.7(a)) Like a tadpole A small cell consisting of a head, a middle piece and a long tail Average length is about 0.05 mm A nucleus contains genetic materials inside the head Middle piece contains a number of mitochondria that provide energy Strongly mobile by beating of the tail Table 3: Ovum (Section 22.1) Characteristics of an ovum (Fig. 22.7(b)) A spherical cell bounded by a plasma membrane and an egg membrane Much larger than the sperm (about 0.1 mm in diameter) Contains a large amount of food reserves in the cytoplasm (for early development of embryo) Nucleus locates near the centre of the ovum Unable to move Moved by sweeping of cilia and contraction of muscular wall of the oviduct Table 4: Sexual maturation (Section 22.2) Marks the onset of sexual maturity Sex organs become functional Sex organs start to secrete sex hormones Puberty Sex hormones stimulate the production of gametes Sex hormones induce secondary sexual characteristics Starts in girls at about 12 and in boys at about 14 2
Bk3 Ch.22 Reproduction in Humans/3 Table 5: Secondary sexual characteristics (Section 22.2) Secondary sexual characteristics Hair grows on face, armpits and around the genital area Male Female Larynx enlarges and voice becomes deeper Muscles become stronger Shoulders broaden Hair grows on armpits and around the genital area Growth and development of breasts Hip girdle broadens More fat deposits under the skin Table 6: Ovulation (Section 22.3) Ovaries contain about 700 000 potential egg cells at birth About 500 will become mature during a woman s lifetime A number of potential egg cells start to develop at the same time during puberty Ovulation (Fig. 22.9) Each ovum is enclosed by a number of follicle cells (a follicle as a whole) Usually only one follicle reaches maturity and contains a mature ovum Mature follicle moves to the border of the ovary It bursts and releases the ovum into the funnel-shaped opening of the oviduct Ruptured follicle left behind develops into a yellow body Takes place about every 28 days in the two ovaries alternately Table 7: Menstruation (Section 22.3) Discharge of unfertilized ovum through the vagina together with unwanted cells, mucus and blood (menstrual flow) Menstruation The whole cycle of development of follicles and changes in uterine lining repeat about every 28 days (menstrual cycle) Exact number of days of menstrual cycle may vary between different individuals Normal feature of a woman s life starting from puberty to the age of about 50 3
Bk3 Ch.22 Reproduction in Humans/4 Table 8: Menstrual cycle (Section 22.3; Figs. 22.10 and 22.11) Event Cause Effects on thickness of uterine lining Result Before ovulation Follicle produces a hormone Induces the inner lining of the uterus to become thickened and have an increased blood supply Provides food and oxygen for the released ovum to develop if it is fertilized by a sperm After ovulation Yellow body produces another hormone Induces the inner lining of the uterus to become even thicker and more richly supplied with blood Prepares for receiving the fertilized ovum If no fertilization Thickened uterine lining gradually breaks down and sloughs off Discharges through the vagina together with unfertilized ovum Table 9: Transfer of sperms during sexual intercourse (Section 22.4) A male becomes sexually excited, blood spaces inside the penis become filled up with blood During sexual intercourse Penis changes from normal, flaccid state to a rigid, erect state Penis is inserted into the vagina of the female Semen is forced out of the penis into the top of the vagina as a result of ejaculation Table 10: Process of fertilization (Section 22.4; Figs. 22.12 and 22.14) Sperms swim through the cervix into the uterus and up the oviduct Only one sperm can fertilize the ovum and the rest will die Process of fertilization The head of a sperm has penetrated the membranes and entered the cytoplasm of the ovum The surface of the ovum undergoes changes that prevent the entrance of other sperms Sperm nucleus moves through the cytoplasm and fuses with the egg nucleus, forming a zygote Table 11: Multiple births (Section 22.4; Fig. 22.15) Fraternal twins (non-identical twins) Identical twins Arise when two ova are released from the ovary at the same time, both ova are fertilized and implanted in the uterus Arise when the cells of an early embryo separate and develop into two embryos Just like ordinary brothers and sisters Look identical because their cells contain the same genetic materials 4
Table 12: Development of the embryo from a fertilized ovum (Section 22.5) Bk3 Ch.22 Reproduction in Humans/5 Implantation (Fig. 22.17) Development of amnion and placenta Development of the embryo Fertilized ovum divides many times by mitotic cell division to form a spherical mass of cells (an embryo) Moves down the oviduct into the uterus Embeds into the uterine lining Becomes surrounded by the amnion Amnion secretes amniotic fluid to fill the amniotic cavity A placenta is formed Embryo continues to grow by repeated cell division together with cell differentiation Two months later, the embryo has developed into a foetus with formation of recognizable organs (Fig. 22.19) A total of 40 weeks development (gestation period) is required before the baby is born Table 13: Amniotic fluid (Section 22.5; Fig. 22.19) Functions of amniotic fluid Acts as a shock absorber and protects the embryo from damage due to vibrations Prevents the embryo from drying up Allows the embryo to move easily Keeps a steady environment for the development of the embryo Table 14: Placenta (Section 22.5; Fig. 22.18) A disc-shaped organ made up of tissues from both mother and embryo Characteristics of the placenta Finger-like villi are formed and projected into blood spaces in the uterine wall Protects the foetus and provides a steady environment for its development The embryo is connected to the placenta by the umbilical cord Table 15: Umbilical cord (Section 22.5; Fig. 22.18) Structure of an umbilical cord Umbilical artery Umbilical vein Carries blood containing carbon dioxide and wastes from the embryo to the placenta Carries blood containing nutrients, oxygen and antibodies to the embryo 5
Bk3 Ch.22 Reproduction in Humans/6 Table 16: Villi (Section 22.5; Fig. 22.18) There are blood capillaries from the embryo inside the villi Characteristics of the villi The walls of the foetus blood capillaries and the mother s blood spaces are very thin Dissolved substances can move easily across them in both directions by diffusion Oxygen, glucose, amino acids, minerals, vitamins and antibodies diffuse from the mother s blood into the embryo s blood Metabolic wastes such as carbon dioxide and urea are carried away by the mother s blood Provide a large surface area for exchange of materials between the embryo and the mother Table 17: The reason for the mother and the embryo have their own blood circulations (Section 22.5) The embryo s blood and the mother s blood are never mixed together Prevents harmful materials in the mother s blood from reaching the embryo Prevents relatively high blood pressure of the mother from damaging the blood capillaries of the embryo Table 18: Birth process (Section 22.6) Foetus changes its position in the uterus a few weeks before birth Birth process (labour) With its head lying downwards just above the cervix Birth begins when the uterine muscles start to contract rhythmically Contractions are weak at first but become stronger and more frequent as labour proceeds Accompanied by pain 6
Bk3 Ch.22 Reproduction in Humans/7 Table 19: Stages of birth process (Section 22.6; Fig. 22.23) First stage of labour Stage of dilation of cervix Stage of expulsion of the foetus Muscle of the cervix dilates to allow foetus s head to pass through Amnion breaks at this stage Amniotic fluid flows out through the vagina and acts as a lubricant for the passage of the foetus Second stage of labour Uterine muscles and abdominal muscles contract powerfully Foetus is pushed through the cervix and the vagina The baby is expelled out Placenta breaks away from the wall of uterine Further contractions of the uterus push the placenta out of the body Table 20: The importance of parental care (Section 22.6) Parental care Mammary glands become well developed and can be stimulated to secrete milk by sucking action of the baby (Fig. 22.25) Important for human development Young are dependent on their parents for food supply, clothing, housing, protection and education over a long period Table 21: The advantages of breast-feeding (Extension Study) (Section 22.6) Contains all essential nutrients that are perfectly matched with baby s needs Provides a balanced diet for energy supply and healthy growth of baby Breast milk Contains antibodies that help the baby to fight against diseases and resist infections Babies fed on breast milk experience less diarrhea, constipation and food allergies Establishes a close relationship between the mother and the baby Table 22: The importance of birth control (Section 22.7) The need of birth control Human population is increasing rapidly (Fig. 22.27) Natural resources on the Earth are being consumed at an ever-increasing rate Table 23: The concept of contraception (Section 22.7) Contraception Prevents pregnancy to occur Can be achieved by preventing the union of gametes or the implantation of embryo 7
Bk3 Ch.22 Reproduction in Humans/8 Table 24: Rhythm method (Section 22.7) Requires a couple to refrain from sexual intercourse for certain days in each month around the time of ovulation Details of rhythm method Sexual intercourse is restricted to the safe period Time of ovulation can be estimated by recording woman s body temperature in the early morning on each day (Fig. 22.28) Sudden rise in temperature indicates that ovulation is about to occur This method is unreliable Table 25: Barrier methods and chemical methods (Section 22.7; Fig. 22.29) Barrier methods Chemical methods Description Male condom A thin rubber tube that is rolled over the man s erected penis before sexual intercourse Female condom Diaphragm Spermicides Contraceptive pills A thin rubber tube that is inserted into the vagina before sexual intercourse A thin dome-shaped rubber disc that is placed over the cervix before sexual intercourse Sperm-killing cream is used at the same time In form of cream, foam or jelly Put into the vagina before sexual intercourse Often used together with a condom or diaphragm Contains synthetic female sex hormones Function Prevents the semen from reaching the vagina or entering the uterus after ejaculation Simple but effective method Gives protection against sexually transmitted diseases Same function as male condom Prevents sperms from entering the uterus Contain chemicals that kill sperms Prevent ovulation and avoid pregnancy Most effective contraceptive method Has side effects for some women 8
Bk3 Ch.22 Reproduction in Humans/9 Table 26: Surgical methods (Section 22.7) Involves cutting of sex ducts through which gametes pass Sterilization Minor operation Highly successful method of contraception Usually not reversible Table 27: Types of sterilization (Section 22.7) Male sterilization (Fig. 22.30) Female sterilization (Fig. 22.31) Vas deferens are tied off and cut Oviducts are tied off and cut Does not affect the ability to have sexual intercourse Can still ejaculate but semen contains no sperms Sperms are still produced but soon degenerate and are absorbed by body Prevents ovum from reaching the uterus Prevents sperms from reaching the ovum Ova are still produced but absorbed by body Ovaries can still produce female sex hormones Woman still has menstrual cycle Table 28: Prevention of implantation of fertilized ovum (Section 22.7) Intra-uterine device (IUD) A flexible plastic coil Fitted inside the uterus This method is very reliable Morning-after pill Taken after intercourse Only used in emergencies 9
Bk3 Ch.22 Reproduction in Humans/10 Glossary Vocabulary 詞彙 Page Description 解釋 scrotum 陰囊 111 a muscular sac containing the two testis situated behind and below the penis in most male mammals seminiferous tubule 精小管 111 a tube in the testis whose lining produces spermatozoa sperm 精子 111, 116 testis (pl. testes) the male gamete of animals 睪丸 111 male reproductive organ which produces sperms Cowper s gland 高柏氏腺 113 two small bodies situated below the prostate gland in male mammals; produces a sticky fluid constituting the seminal fluid epididymis 附睪 113 the long, narrow, convoluted tube which is attached to the testis of higher vertebrates, and carries sperm into the vas deferens erectile tissue 勃起組織 113 the tissue found in the penis; upon contraction of the tissue the penis will become erect ovary 卵巢 113 an organ of female animal which produces ovum and sex hormones oviduct 輸卵管 113 a duct or tube through which the ova pass from an ovary to the uterus ovulation 排卵 113 the release of a mature ovum from the ovary ovum (pl. ova) 卵 113, 116 female gametes penis 陰莖 113 an erectile male reproductive organ used to introduce seminal fluid from a male into a female prostate gland 前列腺 113 a male sex gland surrounding the neck of the urinary bladder; the liquid secreted forms part of the seminal fluid 藏有兩個睪丸的肌肉囊, 在大部分雄性哺乳動物中, 位處陰莖的後下方 睪丸內的管道, 其內膜產生精子 動物的雄性配子 製造精子的雄性生殖器官 在雄性哺乳動物生殖系統的兩個細小的腺體, 位處前列腺以下, 分泌出的黏性液體是精液的一部分 長而窄的捲曲管道, 附在較高等脊椎動物的睪丸之上, 負責把精子帶進輸精管 陰莖裏的組織, 勃起組織收縮時會令陰莖勃起 雌性動物中, 負責製造卵和製造性激素的器官 卵由卵巢運到子宮的管道 從卵巢排出成熟的卵的過程 雌性配子 雄性的生殖器官, 可勃起以把雄性的精液傳送至雌性體內 圍繞膀胱頸部四周的雄性性腺體, 所分泌的液體是精液的一部分 10
Bk3 Ch.22 Reproduction in Humans/11 Vocabulary 詞彙 Page Description 解釋 semen 精液 113 the substance that is a combination of fluids and sperm cells seminal fluid 精液 113 the liquid secreted from male sex glands, mixed with sperms to form semen seminal vesicle 精囊 113 one of a pair of pouches opening to the base of the vas deferens; synthesizes and secretes a proteinaceous secretion, which constitutes a large part of the semen urethra 尿道 5, 113 a duct which carries urine from the bladder to the outside of the body vas deferens 輸精管 113 duct carrying sperm from testis to urethra and then outside cervix 子宮頸 114 the narrow opening of the uterus, which leads into the vagina copulation 交配 114 the act of sexual intercourse by which the seminal fluid of the male is transferred to the reproductive tract of the female uterus 子宮 114 a large structure of the female reproductive duct. It is the site where the embryo develops vagina 陰道 43, 114 the passage from the uterus of a female mammal to the outside of the body clitoris 陰蒂 115 a part of vulva (external reproductive organs) in female mammals hymen 處女膜 115 a membranous diaphragm covering the entrance to the vagina in a female labia (sing. labium) 陰唇 115 any of four folds of tissue of the female external reproductive organ vulva 陰門 115 the external opening of the vagina in female mammals ovum (pl. ova) 卵 113, 116 sperm 精子 111, 116 female gametes the male gamete of animals 結合精子細胞與液體的物質 由雄性性線體分泌的液體, 與精子混合的物質亦稱為精液 呈袋狀, 在體內成對地出現, 與輸精管底部相通, 會製造和分泌出含蛋白質的分泌物, 構成精液的一大部分 將尿液從膀胱帶出體外的管道 把精子從睪丸帶往尿道至體外的管道 子宮通往陰道的窄小開口部分 即性交的行為, 過程中雄性的精液會傳送進雌性的生殖道中 雌性生殖道上的一個大玨構造, 是胚胎發育的位置 雌性哺乳動物中, 從子宮到體外的通道 雌性哺乳動物的外陰 ( 外部生殖器官 ) 的一部分 覆蓋女性陰道入口的隔膜 女性外生殖器官上四摺組織中的其中一摺 雌性哺乳動物的陰道通往體外的開口 雌性配子 動物的雄性配子 11
12 Bk3 Ch.22 Reproduction in Humans/12 Vocabulary 詞彙 Page Description 解釋 puberty 青春期 117 a stage of development in human when the secondary sexual characteristics starts to develop, and boys and girls become more mature both mentally and physically secondary sexual characteristic 第二性徵 117 characteristic, other than the distinct sex organs, that can show the difference between male and female e.g. voice, body size and beard, etc. follicle 卵泡 118 a mass of cells found in the ovaries of mammals, which contains a maturing egg yellow body 黃體 118 a solid mass of tissue developed by the ruptured follicle after ovulation menstruation 月經 119 discharge of uterine tissue and blood from the vagina in women at the end of a menstrual cycle in which fertilization has not occurred ejaculation 射精 120 the process of releasing seminal fluid under the force by the male external reproductive organ menstrual cycle 月經週期 120 the cyclic release of ovum and thickening of the lining of the uterus to receive a fertilized egg; the complete cycle lasts for 28 days in average in female humans fertilization 受精作用 75, 100, 121 the fusion of male and female gametes fraternal twins 異卵雙胎 122 twins which have each developed from a separate egg identical twins 同卵雙胎 122 two individuals developing from a single fertilized egg, and having same hereditary constitution Siamese twins 連體雙胎 122 either of a part of identical twins born with their bodies joined at some point, a result of the incomplete division of the ovum from which the twins developed 人類發育的一個階段, 第二性徵開始變得明顯, 男女童的身心亦漸趨成熟 能顯示雄性與雌性的分別的特徵, 不包括兩性存有的明顯性器官 ; 例子包括聲音 體形和鬍鬚等 哺乳動物卵巢中的細胞球, 內含正在成熟的卵 排卵後, 由裂開的卵泡發育成的一球固體組織 女性因未有受精, 於月經週期結束時經陰道排出子宮組織及血液的現象 雄性外生殖器官因受壓而將帶有精子的精液排出體外的過程 卵從卵巢釋出, 及子宮內膜增厚以準備接收受精卵的週期性循環, 在人類女性中一個完整的週期大約為 28 天 雄性與雌性的配子融合的過程 由不同的卵發育而成的孿生兒 由單一受精卵發育而成的兩個個體, 兩者的遺傳成分完全相同 屬於共卵雙胎的一種, 不同之處在於此類孿生胎兒發育前, 卵未能完全分裂, 因而使他們的身體有一些部位接合, 造成連體情況
Bk3 Ch.22 Reproduction in Humans/13 Vocabulary 詞彙 Page Description 解釋 amnion 羊膜 123 the fluid-filled sac that surrounds and protects the embryo of mammals amniotic cavity 羊膜腔 123 the space between the amnion and foetus in an animal that possesses an amnion amniotic fluid 羊水 123 the fluid secreted by the amnion that fills the amniotic cavity, containing cells of the foetus implantation 植入 123 the attachment of an embryo to the inner wall of the uterus uterine lining 子宮內膜 123 is the internal epithelium of the uterus placenta 胎盤 124 temporary organ of mammals formed partly from the inner lining of the uterus and partly from tissues of the embryo; serves as a connection between mother and embryo during pregnancy and facilitates passage of nutrients and wastes between mother and embryo umbilical artery 臍動脈 124 a blood vessel that carries blood containing carbon dioxide and other wastes from the embryo to the placenta in the umbilical cord umbilical cord 臍帶 124 a tube connecting an embryo with its placenta umbilical vein 臍靜脈 124 a blood vessel that carries blood containing food, oxygen and antibodies from the placenta to the embryo in the umbilical cord villus (pl. villi) 絨毛 124 minute finger-like projections from the intestinal wall, greatly increases the surface area for the absorption of nutrients differentiation 分化 125, 146 the process in development of the body parts of organisms, in which different cell types become specialized, forming structures that are specialized in composition, forms and functions 包圍並保護哺乳動物胚胎的囊狀膜, 內裏充滿稱為羊水的液體 為具有羊膜的動物獨有的構造, 乃羊膜與胎兒之間的空間, 充滿羊水 由羊膜分泌出來的液體, 充滿於羊膜腔內, 含有胎兒的細胞 胚胎附在子宮內壁上的過程 子宮內壁的上皮 哺乳動物的臨時器官, 分別由子宮內壁及胚胎組織兩部分組成 ; 在懷孕時負責連接母親與胚胎, 有助營養素與廢物轉移 在臍帶中, 把含有二氧化碳和其他廢物的血液從胚胎帶到胎盤的血管 連接胚胎與胎盤的管道 在臍帶中, 把含有食物 氧和抗體的血液從胎盤帶到胚胎的血管 從腸壁伸出的細小呈指形構造, 大大增加了養分吸收的面積 生物身體部分的發育過程, 不同種類的細胞變得專門化, 形成有不同成分 形態及進行不同的功能的構造 13
Bk3 Ch.22 Reproduction in Humans/14 Vocabulary 詞彙 Page Description 解釋 foetus 胎兒 125 the embryo of a human from the third month of pregnancy to birth gestation period 妊娠期 125 the period from the formation of a zygote after fertilization, to the birth of young in viviparous animals amniocentesis 羊膜穿刺術 127 a procedure for testing the status of foetus; a sample of amniotic fluid is draw out through the abdomen and test for any chromosome disorder, usually carried out at 14 20 weeks; recommended for pregnant women over age 35 or having a family history of birth defect; there is a risk of miscarriage (usually 1/250 or less) after the procedure Down syndrome 唐氏綜合症 127, 169 a genetic defect caused by failure of separation of chromosome 21 at meiosis in human, resulting in one extra chromosome 21 in the carrier; suffers express characteristics such as heart defects, mental retardation and stunted growth haemophilia 血友病 127 a hereditary disease in which the blood does not clot properly, due to a deficient of clotting factor (factor VIII) in blood serum; is a sex-linked recessive character that the gene codes for factor VIII is located on the X-chromosome; features include continuous bleeding upon mild cuts of the skin or gum ultrasonography 超音波檢查 127 diagnostic imaging in which ultrasound is used to image an internal body structure or a developing foetus 懷孕第三個月起至分娩期內的人類胚胎 胎生動物中, 卵受精後合子形成到幼兒出生的時間 一個檢驗胎兒狀況的步驟, 會利用針刺入孕婦的腹部, 從子宮抽取少量羊水作為樣本, 然後將樣本進行分析, 以檢驗胎兒是否出現基因異常 ; 一般在懷孕的 4 至 20 週進行, 建議 35 歲或以上 或有誕下不正常胎兒紀錄的懷孕婦女進行此測試 ; 進行此測試後, 有 250 分之一的流產可能性 人類的遺傳病, 成因在於減數分裂期間, 第 21 條染色體沒有分離, 導致配子多帶一條第 21 條染色體 ; 患者會發育不良, 出現智力障礙, 並患有先天性心臟病 由於血清缺乏一種凝固元素 ( 第八因子 ) 而引致血液無法正常地凝固, 出現出血不止的情況, 是一種性染色體隱性遺傳," 第八因子 " 的基因是在 X 染色體上 ; 特徵是遇到輕微的割傷 拔牙或外科小手術亦會有出血不止的現象 影像診斷檢查的方法, 其中會利用超聲波, 來顯示出體內結構或發育中胎兒的影像 14
Bk3 Ch.22 Reproduction in Humans/15 Vocabulary 詞彙 Page Description 解釋 birth process 分娩 128 the process by which baby is born, beginning with contractions of the uterus and ending with the expulsion of the foetus and the placenta labour 分娩 128 the process by which childbirth occurs, beginning with contractions of the uterus and ending with the expulsion of the foetus and the placenta mammary gland 乳腺 129 an exocrine gland in the skin of female mammals; synthesizes and secrets milk under the stimulation of female sex hormones (prolactin and oxytocin) parental care 親代照顧 129 a kind of animal behaviour in which the parent will provide their offspring with food, shelter and protection, sometimes also with education in higher animals allergy 過敏反應 130 an immune response made against a normally harmless substance birth control 節育 130 voluntary limitation or control of the number of children born, especially by the planned use of contraceptive techniques breast-feeding 母乳餵哺 130 to make use of milk produced by the mother to feed babies; found to be beneficial to infant s mental and physical development contraception 避孕 130 method of birth control which involves the use of mechanical or chemical agents to prevent the sperm from reaching and fertilizing the ovum human population rhythm method 人口 130 the total number of all the people inhabiting a specified area 安全期避孕法 131 a kind of birth control by counting the date of ovulation at which intercourse is avoided 嬰兒出生的過程 分娩隨子宮收縮開始, 一直至胎兒和胎盤排出時結束 嬰兒出生的過程, 指子宮收縮, 直至胎兒和胎盤排出的整個過程 雌性哺乳動物皮膚中的外分泌腺, 在雌性性激素 ( 促乳素和催產素 ) 的刺激下, 製造和分泌乳汁 一種動物的行為, 動物的親本會為其後代供應食物 居所和保護, 在一些較高等的動物中亦會為後代提供教育 身體對一般無害的物質所產生的免疫反應 人們自發性限制或控制所生孩子數目的方法, 尤指透過有計劃的避孕方法應用來達到節育的成效 利用母體產生的乳汁作為幼兒的食糧 ; 研究指出母乳餵哺對幼兒心理和生理的健康發展均有良好的影響 節育的方法, 其中涉及使用機械性屏障或利用化學劑把精子殺死, 以阻止精子到達卵而導致受精 居住在某特定地區的人的總數 通過計算排卵日期, 避免在特別日子性交以求達致節育的方法 15
Bk3 Ch.22 Reproduction in Humans/16 Vocabulary 詞彙 Page Description 解釋 safe period 安全期 131 the period of time in each menstrual cycle in female, while fertilization is not likely to happen condom 避孕套 132 sheath used to cover the penis to prevent the sperms from getting into the female reproductive tract diaphragm 子宮帽 132 a contraceptive device consisting of a thin flexible disk, usually made of rubber, designed to cover the uterine cervix to prevent the entry of sperm during sexual intercourse contraceptive pill 避孕丸 133 pill containing female hormones to prevent ovulation for birth control spermicide 殺精劑 133 chemical that kills spermatozoa, used as a contraceptive sterilization 絕育 133 the prevention of producing gametes, or offspring in an individual intra-uterine device in vitro fertilization 子宮環 134 a contraceptive device consisting of a flexible plastic coil, works by preventing the fertilized ovum from implanting in the uterus 體外受精 135 an artificial technique, in which the union of male and female gametes to form a zygote is carried out in an artificial environment outside the organism 女性在月經週期中, 受精作用不會發生的時間 套在陰莖上的鞘, 用以防止精子進入到女性的生殖道 避孕工具的一種, 呈碟狀, 一般由橡膠製造, 薄而富彈性, 用以覆蓋子宮頸, 於性交時阻止精子進入子宮 含雌激素的丸劑, 通過防止排卵以達致節育的效果 一種化學品, 用以殺死精子以達致避孕的目的 防止生物製造配子或產下後代 一種避孕工具, 由富有彈性的塑膠環構成, 透過防止受精卵植入子宮以避免懷孕 在生物體外的人工環境下, 雄配子與雌配子結合, 形成合子的人工技術 infertility 不育 135 the inability to produce offspring 不能產下後代 16