Female reproductive system II Enas Omar. Notes are in green

Transcription

1 Female reproductive system II Enas Omar Notes are in green

2 C.Luteal phase a. Interval between ovulation and menstrual flow (15 th - 28 th day.( b. Duration is κ: 2± 14d (t½ = corpus luteum.( c. Day of ovulation = Length of the menstrual cycle - 14d d. Predominant Hormone: Progesterone nc.

3 Corpus luteum Provides necessary hormones for implantation of blastocyst and maintenance of zygote until placenta can take over Corpus luteum is composed mainly of granulosa cells % 80granulosa cells, 20% thecal cells If not fertilization, will regress in about 14 d Avascular scar = corpus albicans

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5 Ovarian Cycle: follicular phase luteal phase ovulation (FORMAT FOR NEXT FEW SLIDES) Endometrial 1 Cycle: 4 14 menstrual proliferative phase (11 d) secretory phase (12d) 28

6 Ovarian Cycle:follicular phase LH surge ovulation FSH and LH in the Follicular phase LH surge lasts 48 h Inc GnRH bursts FSH LH Endometrial Cycle: menstrual proliferative phase (11 d) secretory phase (12d) 28

7 Ovarian Cycle: follicular phase LH surge ovulation Increase in estradiol to stimulate LH surge. Then estradiol has negative feedback on GnRH to reduce LH, FSH. estradiol FSH LH Endometrial Cycle: Proliferative phase neg feedback--g nrh Secretory phase (12d) 28

8 Ovarian Cycle: follicular phase Changes in activin and inhibin in follicular phase. ovulation + FSH _ Granulosa cells Activin inhibin FSH activin inhibin Endometrial Proliferative phase Cycle: menstrual Inhibin : a hormone secreted by sertoli cells in the male & the granulosa cells in the female activin. It inhibits the production of FSH by the ant pituitary. inhibin Activin :if there is no formation of ovum.. It s secreted to enhance FSH secretion. Secretor y phase (12d)28

9 Ovarian Cycle: follicular phase ovulation Changes in progesterone in follicular phase. progesterone activin progesterone 1 Endometrial Cycle:menstrual 4 14 Proliferative phase 11( d( inhibin 28

10 The uterine cycle and normal menstruation: Because of the monthly cyclic production of estrogens and progesterone, the endometrial lining of the uterus passes into three phases. They are; Proliferative phase, Secretory (or luteal phase), and menstrual phase. These changes are mainly to prepare the uterus for implantation

11 At the beginning of each monthly cycle most of the endometrium has been desquamated by menstruation, after that only a thin layer of stroma remains & proliferate under the influence of estrogen. Then endometrial changes occur to produce a highly secretory endometrium to provide appropriate conditions for implantation of a fertilized ovum You can see that the thickness in the beginning is completely different from that of the end

12 1-Proliferative phase It is about 9-11 days in duration. Estrogen secreted in increasing quantities by the developing follicle causes proliferation of the epithelial cells left after endometrial desquamation. Endothelial re-epithelialization occurs within 4-7 days after the beginning of menstruation (when bleeding ceases.) The next 7-10 days the endometrial thickness increases greatly to about 3-5 mm (formation of new endometrial glands and blood vessels.) The mucus strings secreted by the endometrial glands (especially these of the cervix), align in the cervical canal, forming channels that guide sperm in the proper direction from vagina into the uterus.

13 Phase 1 : estrogen Phase 2 : progesterone The length of this phase is remarkably constant at about 14 days. Occurs after ovulation (the second half of the cycle.) Estrogens cause slight additional cellular proliferation, whereas progesterone causes marked swelling and secretory development with further increase in blood supply to the endometrium. Both blood vessels and glands become highly tortuous. Lipid and glycogen deposit greatly in the stromal cells. The peak of the secretory phase is about 1 week after ovulation. At this time, the endometrial thickness reaches to 5-6 mm. During the secretory phase, the endometrium provides appropriate conditions for implantation of a fertilized ovum. The fertilized ovum needs 3-4 days to enter the uterine cavity from fallopian tube and another 4-5 days for implantation. During this intervals uterine secretions (uterine milk) provide nutrition for the early dividing ovum. Once the ovum implants, trophoblastic cells of the blastocyst begin to digest the endometrium.

14 3. Normal menstruation Occurs when fertilization fails to occur during the secretory phase (involution of corpus luteum.) The usual duration of the menstrual flow is 3-5 days (1-8 days range). Blood loss reaches up to 80 ml (average ml). Bleeding can increase because of medications and diseases that affect the clotting mechanism. Formation of a clot indicates abnormality 24hours before menstruation blood vessels leading to the mucosal layers become vasospastic, presumably because of vasoconstrictor types of prostaglandins. The vasospasm + nutrients + hormonal stimulation endometrial necrosis Hemorrhage + Sloughing of outer layers of the endometrium Prostaglandins and desquamated tissues initiate uterine contractions that expel the uterine contents.( necrotic substances ) The menstrual fluid is normally non-clotting because of released fibrinolysin. Clots presence may indicate uterine pathology. Menstrual flow is rich in leukocytes. This outflow of leukocytes may explain the resistance of uterus to infection during menstruation despite the denuded endothelial surface.( a protective mechanism) Two imp things to remember : 1-manstrual fluid has no clots 2- it is rich in leukocytes.

15 Normal menstruation

16 The standard classification for patterns of abnormal bleeding (1)Menorrhagia (hypermenorrhea) is heavy or prolonged menstrual flow during regular period. The presence of clots may not be abnormal but may signify excessive bleeding. (2)Hypomenorrhea (cryptomenorrhea) is unusually light menstrual flow, sometimes only spotting, during regular period. An obstruction such as hymenal or cervical stenosis may be the cause.

17 (3) Metrorrhagia (intermenstrual bleeding) is bleeding that occurs at any time between Not prolonged period but frequent menstrual periods. ) 4( Polymenorrhea describes periods that occur too frequently, usually associated with anovulation and rarely with a shortened luteal cycle. Mostly bleeding phase in the menstrual Is associated with a disease (5)Oligomenorrhea describes menstrual periods that occur more than 35 days apart. Bleeding usually is decreased in amount and associated with anovulation, either from endocrine causes (eg, pregnancy, pituitary-hypothalamic causes, menopause) or systemic causes (eg, excessive weight loss.)

18 Cyclic changes in Cervix, vagina & breasts: -1Cervix -2Vagina -3Breasts Estrogen:make mucus Thinner,more alkaline If spread on slide dries in fern like manner Progesterone:make mucus thick,tenaciuous,more cellular,if spread on slide doesn t fern Estrogen:cornification of vaginal epithelium Progesterone:thick mucus secretion,proliferation of vaginal epithelium and leucocytes infiltration Estrogen:Proliferation of breasts ducts Progesterone:growth of breast lobules & alveoli

19 This diagram shows the relationship b/w hypothalamus, ant pituitary & the ovary Gnrh secreted by the hypothalamus will stimulate the ant pituitary to release LH & FSH and these hormones will stimulate the ovaries to secrete progesterone & estrogen. Estrogens and progestin exert both positive & negative feedback effects on ant pituitary & hypothalamus depending on the stage of the ovarian cycle. Inhibin which is secreted by granulosa cells has a negative feedback effect on the ant pituitary 2011by Saunders, an imprint of Elsevier Inc.

20 H-P-O axis 1.Positive feedback Sex hormones (E) GnRH or LH/FSH E peak ( 200pg/ml) LH/FSH peak During ovulation only. 2.Negative feedback Sex hormones (E) GnRH or LH/FSH Follicular phase: E FSH Luteal phase: E P LH/FSH (formation) E P LH/FSH (regres Cospyrigihto 201n1 by Sa)unders, an

21 Ovarian Cycle: ovulation + Corpus albicans Luteal phase + FSH _ Granulosa cells a Activin inhibin FSH activin 1 Endometrial Cycle: 4 14 Proliferative phase menstrual 11( d( Secretory phase (12d) inhibin 28 The cells that surround the ovum

22 Ovarian Cycle: + Luteal phase Corpus albicans ovulation Levels of estradiol in luteal phase + FSH _ Granulosa cells Activin inhibin estradiol Endometrial Cycle: proliferative phase FSH secretory phase 28 inhibin

23 Ovarian Cycle: follicular phase ovulation Corpus luteum + _ Luteal phase Corpus albicans Changes in estradiol And progesterone in luteal phase. + Produces inhib GnRH _ progesterone estradiol 1 4 mens Endometrial proliferative phase Cycle: 14 secretory phase 28

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25 Functions of estradiol Fat deposition: more subcutaneous fat in women than men Estrogens: hips and thighs fat deposition (prior to menopause) then more abdominal (Men: androgens: abdominal fat deposition ( Skin: increase vascularization of skin, smooth and soft. Bones: estrogen inhibits osteoclastic activity, so height increases after puberty,but epiphyses and shafts of bones unite early and growth stops So the more the testosterone & estrogen, the less the tall

26 Functions of estradiol External female sex organs: at puberty, increase in size of fallopian tubes, uterus and vagina, external genitalia deposition of fat in mons pubis, labia majora & labia minora change vaginal epithelia from cuboidal to stratified type endometrium: proliferation of cells and endometrial glands (important in nutrition of fertilized ovum( Breasts: fat deposition, development of stromal cells, ducts (progesterone, prolactin important in milk production( Estrogen affect the size of the breast,deposition of fat, development of the stromal tissue &growth of the ductile system. Progesterone & prolactin complete the job in converting the breasts into milk-producing organs.

27 This diagram shows the relationship b/w Estrogen secretion & the age: From birth till puberty very little amount of estrogen is secreted. Then levels of estrogen secretion increase at puberty. You can notice cyclical variation during the monthly sexual cycle. During the first few years of reproductive life, further increase in estrogen secretion is shown. Then a progressive decrease in estrogen secretion toward the end of reproductive life & finally almost no estrogen secretion beyond menopause.

28 When estrogen production fall below critical value, the estrogen the estrogen can no longer inhibit the production of gonadotropins FSH & LH instead they are produced in large & continuous quantities.

29 Functions of estrogen and Progesterone: Estrogen Progesterone -1Facilitate growth of follicles -1Causes secretory phase of menstrual cycle -2growth of ovaries, fallopian tubes, uterus, vagina and female external genitalia,breasts duct system and deposit of fat in the breast. -3Produce female 2ry sex characters,body configuration,fat distribution & increase libido -4Produce proliferative phase of Menstrual cycle,++uterine blood flow,musculature and make it more sensitive to oxytocin -2Stimulate developmentof breast lobules & alveoli -3Essentia for maitenance of pregnancy and increase secretion of fallopian tubes essential for nutient of fertilized ovum. -4Decrease sensitivity of uterus to oxytocin -5produce cyclic changes in cervix & vagina -5Produce cyclic changes in cervix & vagina -6Control FSH&LH secretion & causes the LH surge at midcycle -7Has metabolic anabolic effects, cause epiphyseal closure of bones(also ++bone density),decrease serum cholesterol level,++angiotensinogen secretion from liver,increase HDL,--LDL(Cardioprotective) Produce salt & water retention. Increase metabolism and fat deposition, slight increase protein deposition. -6Inhibit LH secretion during pregnancy (producing amenorrhea) -7Thermogenic effect(++body temperature by 0.5 C at ovulation) ++respiratory rate Produce natriuresis No anabolic functions ---alveolar CO2

30 Female sexual act 1-Stimulation of female sexual act : Thinking lead to sexual desire and this desire change during the cycle reaching the peak near ovulation because of high estrogen. Physical stimulation as in male ( perineal region). Same nerve signals. 2-Female erection and lubrication (clitoris): as the penis control by parasympathetic nerves, same mechanism as in male 3-Female orgasm (female climax):analog to emission and ejaculation in male. There is no ejaculation in females

31 Female sexual response --process is similar in males and females: 1)Excitement phase:caused by psychological or physical stimulation; engorgement and erection of clitoris, vaginal congestion -- due to NO, secreted by parasympathetic nerves 2)Plateau phase:intensification of these responses, increased HR, BP, respiratory rate, muscle tension 3)Orgasmic phase:culmination of sexual excitement, intense physical pleasure 4)Resolution phase:returns genitalia and body systems to pre-arousal state

32 Male and female sexual response Differences: Women don t require refractory time before beginning excitation again No ejaculation in the female

33 Female sexual dysfunction may be as high as 45% in women aged yrs mechanisms: psychological illness unknown

34 Menopause Defn:obsolescence of ovaries, no estradiol production, ova only occasional secondary follicle, few primary follicles Occurs at 51.4 yr of age (average( Due to reduction in estrogen, low levels of inhibin, no negative feedback of LH and FSH; therefore, high levels LH and FSH because there is no estrogen & progesterone Can occur naturally, due to surgery or as a result of chemotherapy

35 Women s Health Initiative Increased risk of CHD, stroke, pulm embolis (3x,( breast cancer HRT regimen should not be initiated or continued for primary prevention of CHD الدكتور علق عالنقطة الثانية بس ما سمعت منيح اللي عنده فكرة عن pinnedالموضوع post يحطها بال JAMA 2002

36 pppp Physiological changes in the body during menopause 1-Hot flushes 2-Irritability 3-Anxiety 4- Fatigue 5- Psychic dyspnea 6-Decrease strength of the bones 7-Vaginal dryness 8-Gradual atrophy of genital organs Small dose of estrogen reverse these symptoms Some of these symptoms can develop in men when they reach the age of reduced sexual activity

37 Polycystic ovary syndrome Affects 10% of reproductive age women Characteristics: hyperandrogenemia oligomenorrhea obesity hirsutism Infertility this is the main problem enlarged cystic ovaries Rx: metformin, anti-androgens?

38 Abnormal secretion of the ovaries: 1-Hypogonadism reduce secretion A- Before puberty cause infantile sexual organs, no secondary sexual character and tall female B- After puberty cause infantile sexual organs include the uterus, small vagina, breast atrophy C-Irregularity of menses and amenorrhea. 2-hypersecretion rare (granulosa cell tumor) and mainly cause irregular bleeding.

39 Female fertility: 1-Fertile period of each cycle (4-5 days), before ovulation 2-Rhythm method for contraceptive (the successful rate75%).one of the commonly practiced methods of contraceptive is to avoid intercourse near the time of ovulation at least 2 days before & 2 days after the ovulation. This is a physiological contraceptive. 3- Hormonal suppression of fertility (the pills) : use of estrogen or progesterone in the first half of the cycle prevent ovulation by prevent preovulatory surge of LH secretion by pituitary gland (successful rate90%). 4- Female sterility : A-Failure of ovulation mainly reduce gonadotropin hormone mainly B-Endometriosis, salpingitis( inflammation of fallopian tube, this cause fibrosis,thereby occluding the tubes & preventing sperms from reaching the ovum.) A student asked : what is the cause of ovulation failure? Answer : ovulation is gonadotropin dependent so any thing that affect the availability of gonadotropins during ovulation period can affect this process.