Chapter 19

Size: px

Start display at page:

Download "Chapter 19"

玑业艾
7 years ago
Views:

1 Chapter 17 Reproduction 理

2 Section A General Terminology and Concepts; Sex Determination and Differentation 念

3 The gonads have a dual functiongametogenesis and the secretion of sex hormones. 泌

4 泌 (-) 葉濾刺

5 I. General Principles of Gametogenesis The first stage of gametogenesis is mitosis of primordial germ cells. In the female, mitosis of germ cells occurs exclusively during the individual s embryonic development. In the male, mitosis really begins at puberty and usually continues throughout life. 裂女裂裂不

In the female, mitosis of germ cells occurs exclusively during the

6 聯數裂 (a) 連 (b) 數裂兩聯 (c) 狀 (d) 聯 (e) 裂聯 (crossingover) (f) 聯列 (g) 行數裂 (h) (i) 數裂 DNA 離

7 Crossing-over and random distribution of maternal and paternal chromatids to the daughter cells during meiosis cause genetic variability in the gametes. 數裂聯兩異

8 II. Sex Determination Sex is determined by the two sex chromosomes: Males are XY, and females are XX. The genes directly determine only whether the individual will have testes or ovaries. All the rest of sex differentiation depends on the presence or absence of substances produced by the genetically determined gonads, specifically the testes. 兩 XYXX 了卵 ()

The genes directly determine only whether the individual will have testes or ovaries.

9 III. Sex Differentiation (I) Differentiation of the Gonads Until the sixth week of uterine life, there is no differentiation of urogenital ridge. A single gene on the Y chromosome (SRY) is responsible for the development of testes. In the absence of a Y chromosome, testes do not develop and ovaries do instead. 六 Y SRYY 卵

A single gene on the Y chromosome (SRY) is responsible for the development of

10 (II) Differentiation of Internal and External Genitalia XY SRY (Y) 勒勒

11 女 SRY 卵勒勒卵女

12 (III) Sexual Differentiation of the Central Nervous System and Homosexuality 戀 The size of a particular nucleus in the hypothalamus is twice as large in men as in women. The nucleus is also twice as large in heterosexual men as in homosexual men. 女兩異戀戀兩

hypothalamus is twice as large in men as in women.

13 Section B Male Reproductive Physiology 理

14 I. Anatomy 切 () Leydig cells secret testosterone 泌

15 The vas deferens and the blood vessels and nerves are bound together in the spermatic cord, which passes to the testis though inguinal canal. 索索

16 II. Spermatogenesis 數數裂數裂數裂 One of the cells of each clone reverts to being a primitive spermatogonium. 復

17 () 粒 Acrosome plays an important role in the sperm s penetration of the egg. 卵了

18 Sertoli-cell barrier (1) prevents the movement of many chemical from the blood into the lumen; and (2) different stages of spermatogenesis take place in different environments. (1) (2) 不不行類滑 A. B. 裂 C. D. E. F. G.

different stages of spermatogenesis take place in

19 Sertoli cells (1) nourish developing sperm (2) secret androgen-binding protein 泌 (3) secret inhibin 泌 (4) receive stimulation by testosteone and FSH to secret paracrine agents that stimulate sperm differentiation and influence the function of Leydig cells. FSH 刺泌泌來刺

stimulation by testosteone and FSH to secret paracrine agents that

20 III. Transport of Sperm The epididymis and vas deferens store the sperm, and the spem undergo a further testosteronedependent maturation process in the epididymis. 行 From the seminiferous tubules, the sperm pass through the epididymis, where they are concentrated. Movement of the sperm to the epididymis results from the fluid movement. Movement of the sperm form epidymis into the vas deferens is due to peristaltic contractions of the smooth muscle. 滑

行 From the seminiferous tubules, the sperm pass through the epididymis, where they are concentrated.

21 (I) Erection,() 路降 Nitric oxide stimulates guanylyl cyclase, which catalyzes the formation of cgmp. 刺

22 (II) Ejaculation It is basically a spinal reflex. (1) Sympathetic stimulations cause the smooth muscles contraction (epididymis, vas deferens, ejaculatory ducts, prostate and seminal vesicles) 刺滑 ( 列 ) (2) Contractions of the urethral smooth muscle and the skeletal muscle at the base of the penis. 尿滑

23 IV. Hormonal Control of Male Reproductive Functions 泌 (-) 葉泌濾刺 (I) Control of the Testes 刺

24 (II) Testosterone Testosterone, acting locally on the Sertoli cells, is essential for maintaining spermatogenesis. 泌 Testosterone maintains the accessory reproductive organs and male secondary sex characteristics and stimulates growth of muscle and bone. In many of its target cells, it must first undergo transformation to dihydrotestosterone (prostate) or to estrogen (brain). 刺 ( 列 ) ()

25 Section C Female Reproductive Physiology 女理

26 I. Anatomy 卵卵尿卵

27 II. Ovarian Function 卵 (I) Oogenesis 卵卵裂數裂 ( 卵 ) 卵卵卵數裂 ()

28 Around the third month after conception, the oogonia cease dividing. In the fetus, all the oogonia develop into primary oocyte and in a state of meiotic arrest. The second meiotic division occurs in a uterine tube after ovulation if the secondary oocyte is fertilized. 卵裂卵卵留數裂狀數裂卵卵卵

29 (II) Follicle Growth 濾濾濾濾卵濾卵卵粒卵

30 The cytoplasmic processes of the granulosa cells traverse the zona pellucida and form gap junctions with the oocyte. Through these gap junctions, nutrients and chemical messengers (eg. maintain meiotic arrest) are passed to the oocyte. 粒卵 ( 例數裂 ) 卵

31 The preantral and early antral stages occur throughout infancy and childhood. At the beginning of each menstral cycle, 10 to 25 of these preantral and early antral follicles begin to develop into larger antral follicles. Only the dominant follicle continues to develop into the mature follicle (graafian follicle). As the time of ovulation approaches, The oocyte float free in the antral fluid 濾濾濾濾 ( 拉濾 ) 卵卵

32 (III) Formation of the Corpus Luteum 來濾卵 Granulosa cells and theca cells transform into luteal cells. 粒卵

33 (IV) Sites of Secretion of Ovarian Hormones 卵泌 Granulose cells estrogen, inhibin. 粒 Corpus luteum progesterone, estrogen, inhibin.

34 III. Control of Ovarian Function 卵度卵刺

35 (I) Follicle Development and Estrogen Secretion during the Early and Middle Follicular Phases 濾濾泌濾刺卵濾卵粒 The granulose cell is similar to the Sertoli cell in that it controls the microenvironment in which the germ cell develops and matures, and it is stimulated by FSH. The theca cell is similar to the Leydig cell in that it produces mainly androgens and is stimulated to do so by LH. 粒 FSH 刺卵類 LH 刺

36 泌濾卵 (-) 葉泌濾刺

37 Decrease of plasma FSH concentration may account for the apoptosis of developing follicles. The dominant follicle have more FSH receptors in the granulose cells and LH receptors, induced by FSH, also appear in large number. FSH 度降濾濾粒 FSHFSHLH 數

38 (II) LH Surge and Ovulation 泌卵葉泌泌卵量

39 (III) The Luteal Phase During the luteal phase, under the influence of small amounts of LH, the corpus luteum secretes progesterone and estrogen. Secretion of GnRH and the gonadotropins is inhibited during the luteal phase by the combination of progesterone, estrogen, and inhibin. 量 LH 泌刺泌

40 IV. Uterine Changes in the Menstrual Cycle 卵度卵泌

41 During the proliferative phase, estrogen stimulates growth of the endometrium and myometrium and causes the cervical mucus to be readily penetrable by sperm. Estrogen also induces the synthesis of progesterone receptors in endometrium cells. 刺泌

42 During the secretory phase, progesterone converts the estrogen-primed endometrium to a secretory tissue and makes the cervical mucus relatively impenetrable to sperm. It also inhibits uterine contractions by opposing the stimulatory actions of estrogen and prostaglandins. 泌泌泌不易列

43 During menstruation, both the vasoconstriction and uterine contractions are mediated by prostaglandins produced by the endometrium in response to the drop in plasma estrogen and progesterone. After the initial period of vascular constriction, the endometrial arterioles dilate, resulting in hemorrhage through the weakened capillary walls. 量降列刺

44 VII. Pregnancy (I) Egg Transport 卵 Ciliary motions sweep the egg into the uterine tubes as it emerges onto the ovarian surface. The egg takes 4 days to reach the uterus by uterine-tube ciliary motions. 卵卵卵卵卵卵 4

45 (II) Sperm Transport and Capacitation Beating of the cilia on the inner surface of the probably wafts the sperm toward the uterus. From uterus into the uterine tube is mainly via the sperm s own propulsions. 卵力

46 Capacitation Sperm are not able to fertilize the egg until they have resided in the female tract for several hours and been acted upon by secretion of the tract. (1) Wavelike beats of the sperm tail are replaced by whiplike action. (2) Sperm s plasma membrane becomes capable of fusing with the egg membrane. 留女數卵力力泌 (1) 律浪類更力 (2) 卵

47 (III) Fertilization 行卵卵泌卵卵卵數裂卵

48 (IV) Early Development, Implantation, and Placentation Uterine-tube smooth muscle near the uterus is maintained in a contracted state by estrogen; as plasma progesterone level rise, this smooth muscle relaxes and allows the 32-cell conceptus to pass (3-4 days). 卵滑狀度滑 32- (3-4)

49 The conceptus undergoes cleavage, eventually becoming a blastocyst (consists of trophoblast, inner cell mass and blastocyst cavity), which implants in the endometrium on approximately day 7 after ovulation. 行裂 ( ) 卵 7 行 The trophoblast gives rise to the fetal part of the placenta, whereas the inner cell mass develops into the embryo proper.

50 Although they do not mix, fetal blood and maternal blood both flow through the placenta, exchanging gases, nutrients, hormones, waste products, and other substances. 不兩流行

51 The amnion (amniotic sac) is derived from the inner cell mass. () 來卵

52 (V) Hormonal and Other Changes during Pregnancy 尿率度尿率刺來數

53 The progesterone (inhibit uterine motility) and estrogen (stimulate growth of the uterine muscle mass) required to maintain the uterus during pregnancy come from the corpus luteum for the first 2 months of pregnancy, their secretion stimulated by chorionic gonadotropin produced by the trophoblast. 兩 () ( 刺 ) 來兩泌泌刺刺 During the last 7 months of pregnancy, the corpus luteum regresses, and the placenta (trophoblast) itself produces large amounts of progesterone and estrogen (androgen precursors are produced by fetal adrenal gland). () 量 ()

54 The high levels of progesterone, in the presence of estrogen, inhibit the secretion of GnRH and thereby that of the gonadotropins, so that menstrual cycles are eliminated. 量 GnRH 泌了刺泌 Trophoblast cells secret placental lactogen, which exerts growth hormone-like and prolactinlike effects in the mother; and stimulates the secretion of IGF-II in the fetus. 泌泌類泌刺泌類 -II

55 (VI) Parturition During the last few weeks of pregnancy, as a result of ever-increasing levels of estrogen, the uterine smooth muscle cells synthesize connexin, cervix starts to breakup its collagen fibers, ovaries start to secret relaxin. and the myometrium start to synthesize oxytocin receptors. 滑卵泌

56 泌列葉泌

57 腦下腺後葉分娩時促進子宮收縮之因子 The autonomic neurons to the uterus are of little importance. Progesterone withdrawal does not play a role in parturition. Initiating labor may be due to placental CRH induced androgens secretion from the fetal adrenal cortex. 控制子宮的自主神經元對分娩並不太重要助孕酮分泌下降對分娩而言亦不重要分娩應是胎盤腎皮釋素引發胎兒腎上腺皮質分泌雄性素而開始的催產素前列腺素子宮收縮嬰兒頭部朝下子宮頸伸張

58 (VII) Lactation 泌 The breasts develop markedly during pregnancy as a result of the combined influences of estrogen (duct growth), progesterone (alveoli growth), prolactin, and placental lactogen. ()() 泌泌 Prolactin secretion is stimulated during pregnancy by estrogen acting on the anterior pituitary, but milk is not synthesized because high concentrations of estrogen and progesterone inhibit the milk-producing action of prolactin on the breasts. 葉刺泌泌度了泌

59 As a result of the suckling reflex, large bursts of prolactin (due to inhibition of dopamine) and oxytocin occur during nursing; the prolactin stimulates milk production and the oxytocin causes milk ejection (contraction of the myoepithelial cells). 泌 ( 泌 ) 量泌 () 刺泌降 (PRF) 泌刺降 (PRF) 葉泌泌泌葉泌

女性生殖器官介紹/月經和排卵的關係 (I) (II) (III)

女性生殖器官介紹/月經和排卵的關係 (I) (II) (III) 女性生殖器官介紹 / 月經和排卵的關係 (I) (II) (III) By: 李碧雪 (October 4, 11, 18 & 25, 2010) 女性生殖器官 : 1. 卵巢 2. 內生殖器官 : 輸卵管, 子宮, 陰道 3. 外生殖器官 : 大陰唇, 小陰唇, 陰蒂 4. 乳腺輸卵管 (uterine tubes)