Female Reproductive Physiology 12 February 2022 female reproductive

Female Reproductive Physiology 12 February 2022 female reproductive physiology 1

Physiologic Anatomy n Female reproductive system include n n Two ovaries Female reproductive tract n n Two uterine tube (fallopian tubules) Uterus Vagina All these are known as female internal genitalia 12 February 2022 female reproductive physiology 2

Physiologic Anatomy n Female external genitalia include n n Mons pubis Labia minora, labia majora Clitoris Vestibule of vagina 12 February 2022 female reproductive physiology 3

Female Reproductive System Sacrum (bone) Ovary Uterus Rectum Vagina Cervix Clitoris Labium minor Labium major Urethra From H. T. sherrief Textbook of Physiology 12 February 2022 female reproductive physiology 4

Menstrual Cycle n Reproductive system of female show regular cyclic changes n n Periodic preparation for fertilization and pregnancy In human the cycle is known as menstrual cycle n Periodic vaginal bleeding n Occur with shedding of uterine mucosa (menstruation) 12 February 2022 female reproductive physiology 5

Menstrual Cycle n Length of cycle n Very variable n It is of about 28 days n From start of one menstrual period to the start of the next 12 February 2022 female reproductive physiology 6

Ovarian Cycle n From time of birth n n There are many primodial follicles under the ovarian capsule Each contain an immature ovum 12 February 2022 female reproductive physiology 7

Ovarian Cycle n At the start of the cycle n n Several primodial follicles enlarge Cavity forms around ovum n Antrum n formation Cavity is then filled with fluid (follicular fluid) n One of the follicles becomes dominant 12 February 2022 female reproductive physiology 8

Ovarian Cycle n Other follicles regress n Form Atretic follicle n By n process of APOPTOSIS Up to this point n It is known as the follicular phase of menstrual cycle 12 February 2022 female reproductive physiology 9

Ovarian Cycle Primary follicle Maturing graffian follicle Corpus albicans Matured follicle Mature corpus luteum Corpus hemorrhagieum (early stage) From Physiology Book by H. Sherrief 12 February 2022 Ruptured mature follicle Ovulation (discharged ovum) female reproductive physiology 10

Ovarian Cycle n Cells of theca interna n n Source of circulating estrogens Follicular liquid has n n High estrogen content Secreted by granulosa cells 12 February 2022 female reproductive physiology 11

Ovulation n Occurs at about 14 days of menstrual cycle Ovum is picked by fimbria of fallopian tube Transported to uterus 12 February 2022 female reproductive physiology 12

Ovulation n If it is fertilized n n This is followed by implantation and pregnancy If it is not fertilized n n It is lost and Menstruation occurs 12 February 2022 female reproductive physiology 13

Corpus Haemorrhagicum n The follicle that raptures during ovulation is filled with blood n n Corpus haemorrhagicum Granulosa cells, Thecal cells proliferate 12 February 2022 female reproductive physiology 14

Corpus Luteum n Clotted blood is replaced by n n n Corpus haemorrhagicum n n Luteal cells Rich in lipids Converted into corpus Luteum This is Luteal phase n Of menstrual cycle 12 February 2022 female reproductive physiology 15

Corpus Luteum n If pregnancy occurs n n n Corpus Luteum persist There will be no more mensrual periods until after delivery If there is no pregnancy n n Corpus Luteum begins to degenerate Replaced by scar tissue n Corpus 12 February 2022 Albicans female reproductive physiology 16

Ovarian Follicles n In humans n n No new ova formed after birth During fetal development n n Ovaries contain over 7 millions primodial follicles Many involute before birth 12 February 2022 female reproductive physiology 17

Ovarian Follicles n At time of birth there are n n n About 2 million ova 50% of them Atretic (no opening) 1 million ova undergo n n 1 st meiosis and Enter stage of arrest in prophase 12 February 2022 female reproductive physiology 18

Ovarian Follicles n At time of puberty n n There about 300, 000 ova Only about 500 ova reach maturity n In the course of normal reproductive life 12 February 2022 female reproductive physiology 19

Uterine Cycle Estrogen & progesteron Estrogens 1 7 Menstrual Proliferative phase Follicular phase 12 February 2022 14 21 28 Days Secretory phase Luteal phase female reproductive physiology 21

Uterine Cycle n At end of menstruation n n All but the deep layers of Endometrium have been sloughed Under the influence n Of estrogen from developing follicle n Endometrium increases in thickness from 5 th to 14 th day 12 February 2022 female reproductive physiology 22

Uterine Cycle n Uterine glands lengthen n n This phase is known as n n Blood vessels grow Proliferative Pre – ovulatory Follicular After ovulation n n Estrogen and progesterone are Secreted by corpus luteum 12 February 2022 female reproductive physiology 23

Uterine Cycle n Estrogen and progesterone cause n n n Endometrium to become more vascularized and edematous Glands become coiled and tortuous and begin to secrete This phase n Secretory phase n Length n of this phase is about 14 days It is also known as luteal phase 12 February 2022 female reproductive physiology 24

Uterine Cycle n When corpus luteum regresses n n Hormonal support for Endometrium is withdrawn Endometrium become thinner n There is then spasm and necrosis of wall of spiral arteries n Enhanced 12 February 2022 by PGE female reproductive physiology 25

Uterine Cycle n n Then menstrual flow ensues Menstrual blood predominantly arterial n n Contain tissue debris, prostaglandin Large amount of fibrinolysin n Lyses 12 February 2022 clot female reproductive physiology 26

Uterine Cycle n Normal menstrual cycle n n n Duration of 3 – 5 days Amount of blood lost range from spotting to 80 ml (average 30 ml) After menstruation, new endometrium regenerates from basal layer 12 February 2022 female reproductive physiology 27

Ovarian Hormones n Ovarian hormones are of two types n Sex steroid hormones n Estrogen n & progesterone Peptide hormones n Inhibin n Relaxin 12 February 2022 female reproductive physiology 28

Ovarian Hormones n Estrogen n Steroid hormones Have similar effect on female reproductive physiology Include n n Estradiol, Estrone, Estriol All three commonly referred to as estrogens 12 February 2022 female reproductive physiology 29

Estrogens n C 18 steroid hormones secreted by n n Granular cells of ovarian follicle Corpus lutenum Placenta Also formed from androgens by aromatization n n Androstenedine Estrone Testosterone 17 – Estradiol Estriol 12 February 2022 female reproductive physiology 30

Estrogens n n Stimulates growth of ovarian follicles Stimulates growth of n n Smooth muscle Epithelial lining of female reproductive tract n Uterine tubes contractility & ciliary activity 12 February 2022 female reproductive physiology 31

Estrogens n n Formation of progesterone receptor Endometrial thickness and growth of uterine glands n Proliferative phase 12 February 2022 female reproductive physiology 32

Estrogens n Estrogen and progesterone n n n Responsible for the luteal phase The amount of uterine muscle mass and contractile proteins Uterus become more excitable and more responsive to oxytocin 12 February 2022 female reproductive physiology 33

Estrogen n Responsible for development of n n Female secondary sex characteristics Enlargement of breast, uterus, vagina Narrow shoulders & broad hips Female distribution of fat and hair 12 February 2022 female reproductive physiology 34

Estrogen n Other effects of estrogen n Cause water and electrolytes retention n Wt n n gain before menstruation Increase secretion by sebaceous glands Inhibit formation of acne 12 February 2022 female reproductive physiology 35

Estrogen n n Inhibition of Atherogenesis Lowering of cholesterol Lowering incidence of myocardial infarct Thus lowering n Cardiovascular disease risks 12 February 2022 female reproductive physiology 36

Progesterone n Stimulates further development of endometrial glands n n n Elongate & coiled Secrete glycogen rich fluid Induces thick, sticky mucus of cervix 12 February 2022 female reproductive physiology 37

Control of Ovarian Functions n FSH from pituitary n n Responsible for early maturation of ovarian follicles FSH & LH are n Responsible for the final maturation of the follicles 12 February 2022 female reproductive physiology 38

Control of Ovarian Functions n A burst of LH secretion responsible for n n n Ovulation Formation of corpus luteum C. L then secrete n n Estrogens & progesterone Gn. RH from hypothalamus n Stimulate release of LH & FSH by ant. Pituitary 12 February 2022 female reproductive physiology 39

Control of Ovarian Function n During early part of follicular phase n n FSH is modestly elevated n n Inhibition is low This enhances follicular growth LH secretion is held in check by n Rising estrogen levels n Negative 12 February 2022 feedback female reproductive physiology 40

Control of Ovarian Functions n At 36 to 48 hrs prior to ovulation n n Estrogen feedback becomes positive Initiates a burst of LH secretion n This produces ovulation n About 12 February 2022 9 hrs after the peak of LH female reproductive physiology 41

Control of Ovarian Function n FSH also peaks probably n n Due to strong Gn. RH stimulation During the luteal phase n n Secretion of LH, FSH is low Because of elevated levels of n 12 February 2022 Estrogens, progesterone, inhibin female reproductive physiology 42

Control of Ovarian Functions Progesterone levels Estrogen levels 1 12 February 2022 21 7 14 Days after start of menstrual cycle female reproductive physiology 28 43

Control of Ovarian Functions Gonadotropins FSH LH 1 7 14 21 28 Days of menstrual cycle 12 February 2022 female reproductive physiology 44

Progesterone n n Uterine contraction and contraction of tubes Stimulates breast growth n n Inhibits prolactin n n Glandular tissue To cause milk production Promote renal Na+ excretion 12 February 2022 female reproductive physiology 45

Negative Feedback Control Limbic system Gn. RH Negative feed bacvk LH FSH n Inhibin Estrogen Thecal Granulosa cells Androgens 12 February 2022 n Hypotha lamus Adenohypophysis ovary Hypothalamus n Releases gonatotrophin releasing hormone (Gn. RH) Gn. RH acts on the anterior pituitary n Release LH & FSH female reproductive physiology 46

Negative Feedback Control Limbic system n Gn. RH Negative feed bacvk LH FSH Hypotha lamus Adenohypophysis Inhibin Estrogen Thecal Granulosa cells Androgens 12 February 2022 Ovary n LH acts on thecal cells & granulosa cells Thecal cells produce n Estrogens & androgens female reproductive physiology 47

Negative Feedback Control Limbic system Gn. RH Negative feed bacvk LH FSH n Hypotha lamus Adenohypophysis Inhibin Estrogen Thecal Granulosa cells Androgens 12 February 2022 Granulosa cells produce n n Inhibin Which inhibit production of FSH Ovary female reproductive physiology 48

Fertilization n In humans, fertilization of ovum by sperm n n Usually occurs in mid-position of fallopian tube It involves n Chemo – attraction of n Sperm to ovum by n Substances produced by ovum 12 February 2022 female reproductive physiology 49

Fertilization n Adherence of sperms n n To zona pellucida Penetration of zona pellucida n n By sperm and The Acrosome reaction 12 February 2022 female reproductive physiology 50

Fertilization n Adherence of sperm head to n n n The cell membrane of ovum Breakdown of area of fusion Release of sperm nucleus into cytoplasm of ovum 12 February 2022 female reproductive physiology 51

Fertilization n Usually millions of sperms are deposited in vagina n n Only few thousand reach the ovum Many of them contact the Zona Pellucida 12 February 2022 female reproductive physiology 52

Fertilization n Sperm bind to n n Special sperm receptor (ZP 3) on zona Pellucida This is then followed by Acrosome reaction 12 February 2022 female reproductive physiology 53

Fertilization n Acrosome reaction involves n n Breakdown of the Acrosome Release of enzymes including Acrosin n n Trypsin like enzyme Acrosin facilitates n 12 February 2022 Penetration of the sperm through Zona Pellucida female reproductive physiology 54

Fertilization n When one sperm bind to ovum this is followed by n n Fusion to ovum membrane Facilitated by Fertilin n n A special protein on sperm head Fusion sets in reactions to prevent n Polyspermy n 12 February 2022 Fertilization by many sperms female reproductive physiology 55

Fertilization n The fusion provide the signal that initiates development n n Sperm is drawn into Oocyte complete 2 nd meiotic division Nuclei of sperm & Oocyte unite Zygote begins Embryogenesis 12 February 2022 female reproductive physiology 56

Implantation n Developing embryo (Blastocyst) n n n Moves down the fallopian tube to uterus Takes 3 to 5 days Once the Blastocyst is in contact with Endometrium n Blastocyst is surrounded by n n 12 February 2022 Outer layer of Syncytiotrophoblast cells Inner layer Cytotrophoblasts female reproductive physiology 57

Implantation n Syncytiotrophoblasts n n n Erode the Endometrium Blastocyst burrows into Endometrium This is implantation n n Occurs about 7 days after fertilization It is followed by development of placenta 12 February 2022 female reproductive physiology 58

Hormones of Placenta n Placenta produces the following hormones n n Human chorionic Gonadotropin (h. CG) Human chorionic Somatomammotropin (h. CS) Progesterone Estrogens 12 February 2022 female reproductive physiology 59

Hormones of Placenta n Human chorionic Gonadotropin (h. CG) n n Is a Glycoprotein containing Galactose Produced by Syncytiotrophoblast 12 February 2022 female reproductive physiology 60

Hormones of Placenta n h. CG is primarily a Luteinizing and Luteotrophic hormone n n n Maintains the function of corpus Luteum (CL) Stimulates CL to secrete 17 hydroprogesterone & progesterone Reach peak secretion 3 – 4 weeks after conception 12 February 2022 female reproductive physiology 61

Hormones of Placenta n Its presence in urine n n During early pregnancy Forms the basis for laboratory tests n For 12 February 2022 pregnancy female reproductive physiology 62

Hormones of Placenta n Human chorionic somatomammotropin (h. CS) n n Also produced by Syncytiotrophoblasts Is a protein hormone 12 February 2022 female reproductive physiology 63

Hormones of Placenta n h. CS has n n n Structure of h. CS is n n Lactogenic and Small amount of growth – stimulating effect Similar to that of growth hormone Large amount of h. CS in maternal blood n But little reaches the fetus 12 February 2022 female reproductive physiology 64

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS Pregnenolone Fetus & placenta interact in n 16 -OHDHEAS Progesterone Cortisol corticosteroid n Estradiol Estriol 12 February 2022 DHEAS 16 -OHDHEAS The formation of steroid hormones Placenta synthesizes n n female reproductive physiology Pregnenolone Progesterone 65

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS Pregnenolone 16 -OHDHEAS Progesterone Cortisol corticosteroid Progesterone enter fetal circulation to fetal adrenals n Form substrate formation of n Estradiol Estriol 12 February 2022 DHEAS n Cortisol corticosterone 16 -OHDHEAS female reproductive physiology 66

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS Pregnenolone 16 -OHDHEAS Progesterone Estradiol Estriol 12 February 2022 Cortisol corticosteroid DHEAS 16 -OHDHEAS n Some of pregnenolone also enter fetal circulation Some prgnenolone are formed by fetal liver female reproductive physiology 67

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS These form substrate for n Pregnenolone 16 -OHDHEAS Progesterone Cortisol corticosteroid n Estradiol Estriol 12 February 2022 DHEAS 16 -OHDHEAS female reproductive physiology Dehydroepiandr osterone sulphate (DHEAS) 16 - hydroxydehydroepiandr osterone sulphate (16 OHDHEAS) 68

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS Pregnenolone 16 -OHDHEAS Progesterone Cortisol corticosteroid n These are formed by the fetal adrenals DHEAS and 16 OHDHEAS n Estradiol Estriol 12 February 2022 DHEAS Transported back to placenta 16 -OHDHEAS female reproductive physiology 69

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol DHEAS Pregnenolone 16 -OHDHEAS Progesterone Estradiol Estriol 12 February 2022 Cortisol corticosteroid DHEAS n n DHEAS forms estradiol 16 -OHDHEAS forms estriol Principal estrogen formed n Estriol 16 -OHDHEAS female reproductive physiology 70

Fetoplacental Unit Placenta Fetal adrenal n Cholesterol n DHEAS Pregnenolone 16 -OHDHEAS Progesterone Cortisol corticosteroid Fetal 16 -OHDHEAS n Thus urinary excretion by the mother n Estradiol Estriol 12 February 2022 Principal source of Estriol DHEAS Can be monitored as index of state of the fetus 16 -OHDHEAS female reproductive physiology 71

Contraception n 1. Available methods surgical 1. 2. Vasectomy Tubal ligation Oral contraceptives pills n Estrogen & progestin 12 February 2022 female reproductive physiology 72

Contraception 3. Intra uterine devices (IUD) 1. 2. Copper containing IUD Loop 4. Others 1. 2. 3. 4. Diaphragm Condoms Spermicide Rhythm 12 February 2022 female reproductive physiology 73

Oral Contraceptive Pills n Combination of estrogen and progesterone n Suppress secretion of Gonadotropins n Suppress 12 February 2022 ovulation female reproductive physiology 74

Oral Contraceptive Pills n Progesterone makes n Cervical mucus thick n Un-favorable n n to sperm migration May also interfere with implantation Pills are administered for 21 days n n Withdrawn for 5 – 7 days Permit menstrual flow 12 February 2022 female reproductive physiology 75