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Reproductive Physiology By: Dr. T. Simbini
Introduction <ul><li>General Terminology   </li></ul><ul><li>Primary reproductive organs: gonads (testes in males, ovaries...
Sex Chromosomes <ul><li>Y chromosome necessary for the production of testes </li></ul><ul><li>Testis determining gene prod...
Principles Gametogenesis <ul><li>First stage of gametogenesis is proliferation of primordial germ cells by mitosis. </li><...
Extra notes <ul><li>The human Y chromosome is smaller than the X chromosome. </li></ul><ul><li>Hence hypothesized that  sp...
Embryology of the human reproductive system <ul><li>Primitive gonad develops from the genital ridge (condensation of tissu...
Pathophysiology <ul><li>Chromosomal abnormalities </li></ul><ul><li>Nondisjunction – pair of chromosomes fails to separate...
Pathophysiology <ul><li>Male pseudohermaphroditism  –  occurs when embryonic testes are defective.  </li></ul><ul><li>Test...
Puberty <ul><li>Is the period rapid bodily changes transforming a child into an adult man or woman.  </li></ul><ul><li>Str...
Male Reproductive System <ul><li>During embryonic development, testes are located in the abdomen </li></ul><ul><li>7 th  m...
Male Reproductive System <ul><li>Ejaculatory ducts enter the substance of the  prostate gland  and join the urethra coming...
Blood – testis barrier <ul><li>Walls of  seminiferous  tubules  lined by primitive germ cells and Sertoli cells </li></ul>...
Spermatogenesis <ul><li>Sperm formation starts in boys during adolescence </li></ul><ul><li>A single ejaculate may contain...
Spermatogenesis Spermatogonia Primary spermatocyte Secondary spermatocyte Spermatids Spermatozoa Mitosis (46) 1 st  meioti...
Spermatogenesis <ul><li>Effect of temperature </li></ul><ul><ul><li>Spermatogenesis requires temperatures lower than the i...
Spermatogenesis <ul><li>Functions of Sertoli cells </li></ul><ul><ul><li>Provide blood-testis barrier to chemicals </li></...
Sperm characteristics <ul><li>Sperm is an intricate motile cell, rich in DNA </li></ul><ul><li>Head is mostly chromosomal ...
Erection <ul><li>Mediated by the parasympathetic fibers in the pelvic splachnic nerves (nervi erigentes) </li></ul><ul><li...
Erection MOA <ul><li>Nitrous oxide, NO, is released locally from nerve endings in the endothelial cells of the erectile ti...
Ejaculation <ul><li>Mediated by sympathetic fibers  </li></ul><ul><li>Two part spinal reflex: emission – movement of semen...
SEXUAL INTERCOURSE <ul><li>COITUS OR COPULATION </li></ul><ul><li>AT SOME POINT PENIS IS INSERTED INTO VAGINA </li></ul><u...
THE FOUR PHASES OF SEXUAL CYCLE <ul><li>EXCITEMENT </li></ul><ul><li>PLATEAU </li></ul><ul><li>ORGASM  </li></ul><ul><li>R...
EXCITEMENT <ul><li>CAN BE INITIATED PHYSICALLY (TACTILE STIMULI)AND/OR PSYCHOLOGICALLY </li></ul><ul><li>CLITORIS, SURROUN...
PLATEAU <ul><li>INTENSIFICATION OF CHANGES DURING EXCITEMENT PHASE </li></ul><ul><li>HEART RATE AND BREATHING CHANGES </li...
MALE ORGASM <ul><li>RHYTHMIC CONTRACTIONS DURING SEMEN EXPULSION </li></ul><ul><li>INVOLUNTARY RHYTHMIC THROBBING OF PELVI...
EPIDIDYMUS, VAS DEFERENS, URETHRA: EJACULATION <ul><li>ROUTE OF EXIT OF SPERM </li></ul><ul><li>DUCTUS DEFERNS STORES SPER...
FEMALE ORGASM <ul><li>PARALLELS THAT IN MALES WITH TWO EXCEPTIONS </li></ul><ul><li>NO COUNTERPART TO EJACULATION </li></u...
Mechanism and Effects of Testosterone Activity <ul><li>Testosterone is synthesized from cholesterol </li></ul><ul><li>It m...
TESTOSTERONE: AT PUBERTY <ul><li>spermatogenesis </li></ul><ul><li>accessory sex glands enlarge and become secretory </li>...
Other Physiological effects of testosterone <ul><li>Decreases GnRH secretion via the hypothalamus </li></ul><ul><li>Inhibi...
Testosterone vs DHT <ul><li>Testosterone receptor complexes responsible for maturation of the wolffian duct structures – m...
Male secondary sexual characteristics <ul><li>External genitalia </li></ul><ul><ul><li>Penis increases in size </li></ul><...
Pathophysiology <ul><li>Cryptochidism </li></ul><ul><li>Undescended testes from the abdomen </li></ul><ul><li>Testicular d...
Brain-Testicular Axis <ul><li>Hormonal regulation of spermatogenesis and testicular androgen production involving the hypo...
Brain-Testicular Axis <ul><li>Testicular regulation involves three sets of hormones: </li></ul><ul><ul><li>GnRH, which ind...
Hormonal Regulation of Testicular Function <ul><li>The hypothalamus releases (GnRH)  </li></ul><ul><li>GnRH stimulates the...
CONTROL OF TESTICULAR FUNCTION HYPOTHALAMUS ANTERIOR PITUITARY GnRH + TESTES SERTOLI CELL LEYDIG CELL TESTOSTERONE INHIBIN...
Hormonal Regulation of Testicular Function <ul><li>Feedback inhibition on the hypothalamus and pituitary results from: </l...
ANATOMY OF THE  FEMALE REPRODUCTIVE SYSTEM <ul><li>vagina </li></ul><ul><li>uterus </li></ul><ul><li>cervix </li></ul><ul>...
Vagina Figure 26.16
UTERUS <ul><li>maintains fetus during pregnancy </li></ul><ul><li>musculature contracts to expel fetus at birth </li></ul>
CERVIX <ul><li>lowest portion of the uterus </li></ul><ul><li>projects into vagina </li></ul><ul><li>cervical canal serves...
CLITORIS <ul><li>erectile tissue analogous to penis in male </li></ul><ul><li>sensitive and erotic </li></ul><ul><li>at fo...
LABIA <ul><li>skin folds </li></ul><ul><li>majora- outer </li></ul><ul><li>minora-inner </li></ul><ul><li>around vaginal a...
External Genitalia <ul><li>Lies external to the vagina and includes the mons pubis, labia, clitoris, and vestibular struct...
OVARIES <ul><li>female gonads </li></ul><ul><li>in abdomen </li></ul><ul><li>produce ova </li></ul><ul><li>secrete estroge...
The Ovaries Figure 26.14a
OVIDUCTS <ul><li>link ovaries to uterus </li></ul><ul><li>fallopian or uterine tubes </li></ul><ul><li>pick up ova at ovul...
Female reproductive system <ul><li>Oogenesis During embryonic development oogonia divide by mitosis and form  primary oocy...
Follicle growth <ul><li>Begins as primordial follicles – one primary oocyte + single layer of granulosa cells </li></ul><u...
Ovarian Cycle <ul><li>Female reproductive system shows regular cyclic changes.  </li></ul><ul><li>Length variable between ...
Follicular Phase <ul><li>10-12 primary follicles develop into antral folllicles </li></ul><ul><li>Day 6 one follicle becom...
Follicular Phase Figure 26.20
Luteal Phase <ul><li>After ovulation, the ruptured follicle collapses, granulosa cells enlarge, and along with internal th...
Establishing the Ovarian Cycle <ul><li>During childhood, ovaries grow and secrete small amounts of estrogens that inhibit ...
Uterine (Menstrual) Cycle <ul><li>Series of cyclic changes that the uterine endometrium goes through each month in respons...
Menses <ul><li>Normal menstruation 3-5 days. </li></ul><ul><li>Average blood flow 30ml </li></ul><ul><li>Flow affected by ...
Gonadotropins, Hormones, and the Ovarian and Uterine Cycles Figure 26.22a, b
Hormonal control of the mensrual cycle <ul><li>Control of Ovarian function </li></ul><ul><ul><li>Regulated by GnRH, FSH, L...
Effects of LH surge <ul><li>Oocyte is induced to complete its first meiotic division </li></ul><ul><li>Antrum size and blo...
Corpus luteum Hormonal Activity <ul><li>Secretes large quantities of progesterone and oestrogen </li></ul><ul><li>In prese...
Hormonal control of uterine changes <ul><li>Proliferative phase: rising oesrogen stimulates growth of endometrium and myom...
Cyclic changes in Uterine cervix <ul><li>Oestrogen makes cervical mucus thinner, more alkaline – promote survival and tran...
Vaginal cycle <ul><li>Oestrogen – vaginal epithelium cornified,  </li></ul><ul><li>Progesterone – thick mucus secreted, ep...
Gonadotropins, Hormones, and the Ovarian and Uterine Cycles Figure 26.22c ,d
<ul><li>Estrogen levels rise during puberty </li></ul><ul><ul><li>Promote oogenesis and follicle growth in the ovary </li>...
<ul><li>Growth of the breasts </li></ul><ul><li>Increased deposition of subcutaneous fat, especially in the hips and breas...
Cyclic changes in Breast <ul><li>Oestrogens : proliferation of mammary ducts </li></ul><ul><li>Progesterone : growth of lo...
Indicators of ovulation <ul><li>Secretory pattern indicative of functional corpus luteum </li></ul><ul><li>Rise in basal t...
CONTROL OF FSH AND LH SECRETION DURING FOLLICULAR PHASE HYPOTHALAMUS ANTERIOR PITUITARY GRH + OVARY LOW LEVELS OF ESTROGEN...
CONTROL OF LH SURGE  AT OVULATION HYPOTHALAMUS ANTERIOR PITUITARY GNRH + OVARY HIGH LEVELS OF ESTROGEN OVULATION FSH LH MA...
FEEDBACK CONTROL DURING LUTEAL PHASE  HYPOTHALAMUS ANTERIOR PITUITARY GNRH + OVARY HIGH LEVELS OF PROGESTERONE LH CORPUS L...
Oestrogen functions <ul><li>Stimulates growth of ovary and  follicles </li></ul><ul><li>Stimulates growth of smooth muscle...
Progesterone effects <ul><li>Stimulates endometrial glands to secrete </li></ul><ul><li>Induces thick, sticky cervical muc...
FERTILIZATION <ul><li>in oviduct </li></ul><ul><li>sperm deposited in vagina at ejaculation </li></ul><ul><li>travel to ov...
HORMONES OF PREGNANCY <ul><li>placenta is organ of exchange </li></ul><ul><li>placenta secretes human chorionic gonadotrop...
PARTURITION  <ul><li>Pregnacy duration averages 40 weeks from last menstrual period </li></ul><ul><li>Oxytocin receptors o...
LACTATION <ul><li>mammary glands or breasts </li></ul><ul><li>milk producing glands and fat </li></ul><ul><li>action of es...
Mammary Glands <ul><li>Modified sweat glands consisting of 15-25 lobes that radiate around and open at the nipple  </li></...
Breast Cancer <ul><li>Usually arises from the epithelial cells of the ducts </li></ul><ul><li>Risk factors include: </li><...
Breast Cancer: Detection and Treatment <ul><li>Early detection is by self-examination and mammography </li></ul><ul><li>Tr...
contraception <ul><li>Hormonal </li></ul><ul><li>Steriliztion and abortion </li></ul><ul><li>Barrier methods </li></ul><ul...
hormonal <ul><li>Progesterone Only Method  </li></ul><ul><li>Mini Pills …prevents ovulation/hampers sperm motility and als...
hormonal <ul><li>Depo-Provera, a progesterone available in many countries, is administered by injection once every three m...
<ul><li>Norplant consists of a set of small, soft tubes that are surgically implanted under the skin of a woman's arm, whe...
hormonal <ul><li>The &quot;morning-after pill&quot;--a series of pills containing either high dosages of both estrogen and...
<ul><li>combination of synthetic estrogen and synthetic progesterone, which inhibit ovulation by simulating the biochemica...
Abortion/Sterilization <ul><li>vasectomy--the blocking or severing of the ductus deferentes (or vasa deferentia  </li></ul...
Barrier methods <ul><li>Diaphrams  </li></ul><ul><li>Condoms  </li></ul><ul><li>Spermacidals  </li></ul><ul><li>Cervical C...
BARRIER METHODS CONT. <ul><li>Intrauterine Devices: plastic or metal objects in a variety of shapes that are implanted ins...
Natural  family planning <ul><li>Abstinence (100% effective!!!!!!) </li></ul><ul><li>Withdrawal  </li></ul><ul><li>Fertili...
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Reproduction dr t simbini

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Reproduction Physiology

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  • MIS continues to be secreted by sertoli cells to a peak in 1-2 old boys thereafter declines throughout life In girls mis is produced by granulosa cells in small folliclesin the ovaries
  • Transcript of "Reproduction dr t simbini"

    1. 1. Reproductive Physiology By: Dr. T. Simbini
    2. 2. Introduction <ul><li>General Terminology </li></ul><ul><li>Primary reproductive organs: gonads (testes in males, ovaries in females) </li></ul><ul><li>In both sexes gonads serve a dual function namely: </li></ul><ul><li>Gametogenesis : production of reproductive cells (gametes – spermatozoa by males, ova by females) </li></ul><ul><li>Secretion of sex hormones (testosterone in male, estradiol and progesterone in female). </li></ul><ul><li>Male sex hormones are called androgens have mascularising actions </li></ul><ul><li>Oestradiol is the primary oestrogen in females. </li></ul><ul><li>Progesterone ( pro- for gestatus – to give birth) hormone for maintaining pregnancy </li></ul><ul><li>In the foetus the primitive, bipotential sex gland or gonad differentiates at about 7 to 8 weeks of intrauterine life </li></ul><ul><li>Differentiation is genetically determined </li></ul><ul><li>Sex chromosome XX gonad turns into ovary </li></ul><ul><li>XY turns into testis </li></ul><ul><li>Gonads are quiescent during childhood </li></ul><ul><li>Awaken during puberty activated by gonadotropins from the anterior pituitary </li></ul><ul><li>Hormones cause the appearance of typical adult male or female features </li></ul><ul><li>In human females ovarian function regresses after a number of years and sexual cycles seize (menopause) </li></ul><ul><li>In males slow decline in gonadal function with advancing age but ability to father children persists </li></ul>
    3. 3. Sex Chromosomes <ul><li>Y chromosome necessary for the production of testes </li></ul><ul><li>Testis determining gene product called SRY (sex determining region of the Y chromosome) </li></ul><ul><li>SRY acts as a transcription factor that initiates transcription of a cascade of genes necessary for testicular differentiation </li></ul><ul><li>Gene for SRY located near the tip of the short arm of the human Y chromosome </li></ul><ul><li>Male cells with the diploid number of chromosomes have both X and Y chromosome patterns. </li></ul><ul><li>Female cells contain two X chromosomes </li></ul><ul><li>A result of meiosis during gametogenesis each ova contains a single X chromosomes </li></ul><ul><li>Half the normal sperms contain X chromosome </li></ul><ul><li>Other half contain Y chromosome </li></ul>
    4. 4. Principles Gametogenesis <ul><li>First stage of gametogenesis is proliferation of primordial germ cells by mitosis. </li></ul><ul><li>All of the dividing cell’s 46 chromosomes are replicated. Each of the daughter cells receives a full set of the 46 chromosomes – identical to those of the original cell </li></ul><ul><li>Timing of mitosis varies greatly in males and females </li></ul><ul><li>In females, mitosis occurs exclusively during the individual’s embryonic development </li></ul><ul><li>In males, some mitosis occurs in the embryo to generate the population of germ cells. Mitosis really begins at puberty and continues throughout life </li></ul><ul><li>Second stage of gametogenesis is meiosis </li></ul><ul><li>Each resulting gamete receives only 23 chromosomes from a 46 chromosome germ cell, 1 chromosome from each homologous pair </li></ul><ul><li>A mature sperm and ovum each has only 23 chromosomes </li></ul><ul><li>Their union at fertilisation results in a full complement of 46 chromosomes </li></ul><ul><li>Meiosis occurs in males during maturation of the sperm from spermatogonia to spermatocytes (in puberty) </li></ul><ul><li>In females first meiotic division starts in-utero and is completed prior to ovulation, the second meiotic division is completed after fertilisation. </li></ul>
    5. 5. Extra notes <ul><li>The human Y chromosome is smaller than the X chromosome. </li></ul><ul><li>Hence hypothesized that sperms containing the Y chromosome are lighter and are able to “swim” faster up the female genital tract, thus reaching the ovum more rapidly </li></ul><ul><li>Supposedly accounts for the fact that the number of males born is slightly greater than of females </li></ul><ul><li>Timing of sex of baby </li></ul>
    6. 6. Embryology of the human reproductive system <ul><li>Primitive gonad develops from the genital ridge (condensation of tissue near the adrenal gland) </li></ul><ul><li>Gonad develops a cortex and a medulla </li></ul><ul><li>Until 6 th week, these structures are identical in both sexes </li></ul><ul><li>In genetic males, the medulla develops during 7 th and 8 th wks into a testis and cortex regresses </li></ul><ul><li>Leydig and Sertoli cells appear, testosterone and mullerian inhibiting substance are secreted </li></ul><ul><li>In genetic females, the cortex develops into the ovary and the medulla regresses. The embryonic ovary does not secrete hormones </li></ul><ul><li>In normal female foetus the mullerian duct system develops into uterine tubes (oviducts) and a uterus </li></ul><ul><li>In normal male foetus, the wolffian duct system develops into the epididymis and vas deferens </li></ul><ul><li>By the 8 th wk the external genitalia are similarly bipotential </li></ul><ul><li>The urogenital slit in males disappears or remains open and female genitalia form </li></ul><ul><li>With functional testes male internal and external genitalia develop </li></ul><ul><li>Leydig cells of the foetal testis secrete testosterone </li></ul><ul><li>Sertoli cells secrete mullerian inhibiting substance (MIS/MRF). These act unilaterally </li></ul><ul><li>MIS causes regression of the mullerian ducts by apoptosis on the side it is secreted </li></ul><ul><li>Testosterone fosters the development of the vas deferens and related structures from the wolffian ducts. It induces the formation of male external genitalia </li></ul><ul><li>Development of the brain affected androgens early in life in some species </li></ul>
    7. 7. Pathophysiology <ul><li>Chromosomal abnormalities </li></ul><ul><li>Nondisjunction – pair of chromosomes fails to separate, hence both chromosomes go to one daughter cell </li></ul><ul><li>Gonadal dysgenesis (XO chromosomal pattern) – gonads are rudimentary, or absent. External female genitalia develop. Stature is short, webbed neck, other congenital abnormalities are often present. No maturation occurs at puberty. (Turner’s syndrome) </li></ul><ul><li>Seminiferous tubule dysgenesis (Klinefelter’s syndrome) – XXY pattern. Have genitalia of a normal male. Testosterone at puberty is often great enough for development of male characteristics. </li></ul><ul><li>Seminiferous tubules are abnormal and higher than normal incidence of mental retardation </li></ul><ul><li>sterility </li></ul><ul><li>“ Superfemale” - XXX pattern is not associated with any characteristic abnormalities </li></ul><ul><li>Hormonal abnormalities </li></ul><ul><li>Development of male external genitalia occurs in genetic males in response to androgens secreted by the embryonic cells </li></ul><ul><li>Male external genitalia may develop in genetic females exposed to androgens from other sources during the 8 th to 13 th wks of gestation. Results in female pseudohermaphroditism. </li></ul><ul><li>Pseudohermaphrodite – an individual with the genetic constitution and gonads of one sex and the genitalia of another </li></ul><ul><li>Can be due to congenital virilizing adrenal hyperplasia or maternal exposure to androgens </li></ul>
    8. 8. Pathophysiology <ul><li>Male pseudohermaphroditism – occurs when embryonic testes are defective. </li></ul><ul><li>Testes secrete MIS hence genetic males with defective testes have female internal genitalia </li></ul><ul><li>Androgen resistance – male hormones cannot exert their full effects on the tissues. One form of androgen resistance 5 – α reductase deficiency, the enzyme responsible for the formation of dihydrotestosterone, active form of testosterone, is decreased. </li></ul><ul><li>Loss of receptor function – testicular feminising syndrome. MIS is present and testosterone is secreted at normal or elevated levels. </li></ul><ul><li>The external genitalia are female, vagina ends blindly because there are no female internal genitalia. </li></ul><ul><li>Individuals develop enlarged breasts at puberty and are considered female - diagnosis when they seek medical office because of lack of menstruation. </li></ul>
    9. 9. Puberty <ul><li>Is the period rapid bodily changes transforming a child into an adult man or woman. </li></ul><ul><li>Strictly defined as the period when endocrine and gametogenic functions of the gonads have first developed to the point where reproduction is possible. </li></ul><ul><li>Takes about 3 to 5 years. </li></ul><ul><li>Two principle components: </li></ul><ul><ul><li>Sudden growth spur. Height increases by as much as 8-11cm in a year </li></ul></ul><ul><ul><li>Appearance of secondary sexual characteristics </li></ul></ul><ul><li>In girls, first event is thelarche, development of breasts, then puberache – development of axillary and pubic hair, then menarche – first menstrual period. </li></ul><ul><li>First periods are anovulatory, regular ovulation occurs about a year later. </li></ul><ul><li>Age at time of puberty is variable. </li></ul><ul><li>Average age is 12 years for girls and 14 years for boys </li></ul><ul><li>Mechanism by which puberty is initiated is not fully understood. </li></ul>
    10. 10. Male Reproductive System <ul><li>During embryonic development, testes are located in the abdomen </li></ul><ul><li>7 th month of gestation testes descend into the scrotum </li></ul><ul><li>Essential for normal sperm production – requires temperature significantly lower than normal internal body temperature </li></ul><ul><li>Achieved by a heat exchange mechanism in the blood vessels supplying the testes </li></ul><ul><li>Spermatic arteries to the testes are tortuous </li></ul><ul><li>Blood runs parallel but in opposite direction to blood in the pampiniform plexus of spermatic veins – forming a counter current exchange of heat and testosterone </li></ul><ul><li>Testes made up of convoluted seminiferous tubules – walls of which the spermatozoa are formed from primitive germ cells. </li></ul><ul><li>Tubules drain into a network of ducts (rete testes) in the head of the epididymis. </li></ul><ul><li>In the epididymis the sperm attain maturation. The epididymis is so convoluted it measures 6m if straightened out </li></ul><ul><li>Epididymis draining each testis leads to a vas deferens. </li></ul><ul><li>Vas deferens carries the spermatozoa to the ampulla – site for mixing with seminal vesicle secretions . </li></ul><ul><li>After entering the abdomen – course to the back of the urinary bladder to become ejaculatory ducts </li></ul><ul><li>Seminal vesicles lie behind the bladder and into the seminal vesicles </li></ul>
    11. 11. Male Reproductive System <ul><li>Ejaculatory ducts enter the substance of the prostate gland and join the urethra coming from the bladder. </li></ul><ul><li>Seminal vesicles, prostate and bulbourethral glands constitute the accessory sex glands </li></ul><ul><li>The spermatozoa, mixed with ejaculatory secretions from the accessory sex glands constitute the semen that exits the body through the penile urethra. </li></ul><ul><li>Seminal plasma is the fluid portion of the an ejaculum </li></ul><ul><li>Split ejaculate – first fraction – Cowper’s gland, prostate gland, second fraction – testes, epididymis, vas deferentia, third fraction – seminal vesicles </li></ul><ul><li>Seminal plasma composition (Confirmed by split ejaculate techniques) </li></ul><ul><ul><li>Fructose – seminal vesicles </li></ul></ul><ul><ul><li>Prostaglandins – seminal vesicles </li></ul></ul><ul><ul><li>Cholesterol – prostate </li></ul></ul><ul><ul><li>Spermin – prostate </li></ul></ul><ul><ul><li>Alpha glucosidase – epididymis </li></ul></ul><ul><ul><li>Leucocytes – epididymis, prostate (T. Simbini et al .). </li></ul></ul>
    12. 12. Blood – testis barrier <ul><li>Walls of seminiferous tubules lined by primitive germ cells and Sertoli cells </li></ul><ul><li>Tight junctions between adjacent Sertoli cells form a blood – testis barrier, prevents many large molecules from the interstitial tissue near the basal lamina (basal compartment) to the tubular lumen (adlumnal compartment) </li></ul><ul><li>Steroids penetrate this barrier with ease </li></ul><ul><li>Fluid in seminiferous tubules different from plasma : very little protein and glucose, rich in androgens, estrogens,inositol, potassium </li></ul><ul><li>Barrier protects germ cells from blood-borne noxious agents, prevents autoimmune response to the germ cells </li></ul>
    13. 13. Spermatogenesis <ul><li>Sperm formation starts in boys during adolescence </li></ul><ul><li>A single ejaculate may contain 150 to 300 million sperms suspended in 2 to 5 mls of fluid </li></ul><ul><li>From spermatogonia to fully formed sperm takes about 74 days in man </li></ul><ul><li>Capacitation or ripening of the sperms in the epididymis requires another 2 wks. </li></ul>
    14. 14. Spermatogenesis Spermatogonia Primary spermatocyte Secondary spermatocyte Spermatids Spermatozoa Mitosis (46) 1 st meiotic division (23) 2 nd meiotic division (23) Differentiation Stages from spermatogonia to spermatids appear to be androgen independent. The maturation of spermatids to spermatozoa depends on androgens acting on the Sertoli cells in which the developing spermatozoa are embedded. FSH acts on the Sertoli cells to facilitate the last stages of spermatid maturation. Spermatozoa leaving the testicle are not fully mobile. Continue maturation and acquire motility during passage through the epididymis. Motility is further improved by relaxin (prostate?). Capacity of sperm to fertilise is further enhanced in the female genital tract. Capacitation enhances sperm adherence to the ovum.
    15. 15. Spermatogenesis <ul><li>Effect of temperature </li></ul><ul><ul><li>Spermatogenesis requires temperatures lower than the internal body temperature. </li></ul></ul><ul><ul><li>Testes are maintained at 32 o C. </li></ul></ul><ul><ul><li>Kept cool by air circulating around scrotum and heat exchange between spermatic arteries and veins. </li></ul></ul><ul><ul><li>Hot baths and tight insulated underpants reduce sperm counts by as much as 90%. </li></ul></ul><ul><ul><li>Seasonal variation in sperm counts. Highest when? </li></ul></ul>
    16. 16. Spermatogenesis <ul><li>Functions of Sertoli cells </li></ul><ul><ul><li>Provide blood-testis barrier to chemicals </li></ul></ul><ul><ul><li>Nourish developing sperm </li></ul></ul><ul><ul><li>Secrete luminal fluid, including androgen-binding protein </li></ul></ul><ul><ul><li>Receive stimulation by testosterone and FSH to secrete paracrine agents that stimulate sperm production and maturation </li></ul></ul><ul><ul><li>Secrete inhibin, inhibits FSH secretion </li></ul></ul><ul><ul><li>Phagocytize defective sperm </li></ul></ul><ul><ul><li>Secrete during embryonic life, mullerian inhibiting factor, causes female duct system to regress </li></ul></ul><ul><ul><li>Contain aromatase, enzyme responsible for conversion of androgens to estrogens </li></ul></ul><ul><ul><li>Produce estrogens </li></ul></ul>
    17. 17. Sperm characteristics <ul><li>Sperm is an intricate motile cell, rich in DNA </li></ul><ul><li>Head is mostly chromosomal material </li></ul><ul><li>Covering the head is the acrosome, enhances sperm penetration of ovum </li></ul><ul><li>Motile tail has proximal portion rich in mitochondria </li></ul><ul><li>Human beings ejaculate 40-300mil /ejaculate </li></ul><ul><li>WHO 20mill/ml normal </li></ul><ul><li>Sperm conc below 20mill oligospermia </li></ul><ul><li>Absence of spermatozoa azospermia </li></ul><ul><li>Sperm counts >250mill /ml polyspermia </li></ul><ul><li>Sperm motility essential for fertility. </li></ul><ul><li>Immotile sperm cannot penetrate cervical mucus </li></ul><ul><li>To be fertile >50% of sperm are progressively motile (WHO) </li></ul><ul><li>Human sperm has a high percentage of abnormal sperm (70%) </li></ul><ul><li>Acceptable morphology >30% (WHO) </li></ul>
    18. 18. Erection <ul><li>Mediated by the parasympathetic fibers in the pelvic splachnic nerves (nervi erigentes) </li></ul><ul><li>VIP and acetylcholine co transmitters. VIP (vasoactive intestinal peptide) produces vasodilation – erectile tissue fill with blood. Acetylcholine acts on muscarinic receptors to decrease NA release (a vasoconstrictor) </li></ul><ul><li>NO synthatase catalyses the formation of NO (nitric oxide) a powerful vasodilator. ?? Viagra (MOA) </li></ul>
    19. 19. Erection MOA <ul><li>Nitrous oxide, NO, is released locally from nerve endings in the endothelial cells of the erectile tissue(corpus carvenosum), when stimulated. Nitrous oxide is made with the aide of the enzyme NO synthase </li></ul><ul><li>The NO then diffuses out of the cell in which it was synthesised, and into neighbouring cells (paracrine effect). NO acts on the enzyme guanylyl cyclase to produce the intracellular mediator(second messenger) guanosine monophosphate (cGMP) </li></ul><ul><li>cGMP acts as a vasodilator by relaxing smooth muscle in the blood vessels of the corpus cavernosum </li></ul><ul><li>This leads to increased blood flow into the penis and hence an erection. </li></ul><ul><li>A phosphodiesterase enzyme, PDE-5 hydrolyses the cGMP to an inactive form, </li></ul><ul><li>In healthy male this acts as a regulatory system </li></ul><ul><li>Men suffering from erectile dysfunction (ED) may produce insufficient NO and hence insufficient amounts of cGMP, which are of course broken down by the PDE-5 enzyme. </li></ul><ul><li>Sildenafil Citrate (Viagra) binds with the active site of the PDE enzyme, thus preventing it from hydrolysing cGMP. </li></ul><ul><li>Allowing cGMP to remain in its active form for longer and hence have a prolonged vasodilatory effect – sustaining an erection </li></ul>
    20. 20. Ejaculation <ul><li>Mediated by sympathetic fibers </li></ul><ul><li>Two part spinal reflex: emission – movement of semen into urethra & ejaculation – propulsion of semen out of urethra at time of orgasm </li></ul><ul><li>Afferent fibers are mostly touch receptors in the glans penis, reach the spinal cord through the internal pudental nerve </li></ul><ul><li>Sympathetic response integrated in the upper lumber segments of the spinal cord, effected by contraction of smooth muscle of vasa differentia and seminal vesicles </li></ul>
    21. 21. SEXUAL INTERCOURSE <ul><li>COITUS OR COPULATION </li></ul><ul><li>AT SOME POINT PENIS IS INSERTED INTO VAGINA </li></ul><ul><li>SEXUAL RESPONSE CYCLE </li></ul>
    22. 22. THE FOUR PHASES OF SEXUAL CYCLE <ul><li>EXCITEMENT </li></ul><ul><li>PLATEAU </li></ul><ul><li>ORGASM </li></ul><ul><li>RESOLUTION </li></ul>
    23. 23. EXCITEMENT <ul><li>CAN BE INITIATED PHYSICALLY (TACTILE STIMULI)AND/OR PSYCHOLOGICALLY </li></ul><ul><li>CLITORIS, SURROUNDING PERINEAL AREA AND PENIS ARE PRIMARY AREAS FOR THIS </li></ul><ul><li>OTHER SENSITIVE AREAS MAY CONTRIBUTE IF STIMULATED, BREASTS, TESTICLES, ETC. </li></ul><ul><li>ERECTION OF PENIS AND CLITORIS RESULT (CLITORIS IS A HOMOLOGUE OF THE PENIS) </li></ul><ul><li>LUBRICATION FROM VAGINAL CAPILLARIES, GLANDS AT OPENING OF VAGINA AND PENIS PREPARE FOR INTERCOURSE </li></ul>
    24. 24. PLATEAU <ul><li>INTENSIFICATION OF CHANGES DURING EXCITEMENT PHASE </li></ul><ul><li>HEART RATE AND BREATHING CHANGES </li></ul><ul><li>MUSCLE TENSION INCREASES </li></ul><ul><li>VAGINA TIGHTENS AROUND PENIS HEIGHTENING SENSATION </li></ul><ul><li>UTERUS RAISES UPWARD CREATING SPACE FOR EJACULATE </li></ul>
    25. 25. MALE ORGASM <ul><li>RHYTHMIC CONTRACTIONS DURING SEMEN EXPULSION </li></ul><ul><li>INVOLUNTARY RHYTHMIC THROBBING OF PELVIC MUSCLES </li></ul><ul><li>BREATHING AND HEART RATE INCREASED </li></ul><ul><li>EMOTIONAL RESPONSE: RELEASE AND COMPLETE GRATIFICATION </li></ul><ul><li>RESOLUTION PHASE INVOLVES SYMPATHETIC VASOCONSTRICTION </li></ul><ul><li>A REFRACTORY PERIOD PREVENTS MULTIPLE ORGASMS IN THE MALE </li></ul>
    26. 26. EPIDIDYMUS, VAS DEFERENS, URETHRA: EJACULATION <ul><li>ROUTE OF EXIT OF SPERM </li></ul><ul><li>DUCTUS DEFERNS STORES SPERM </li></ul><ul><li>DURING EMMISSION PHASE OF EJACULATION SPERM ARE EMPTIED INTO URETHRA BY SYMPATHETICALLY INDUCED CONTRACTIONS </li></ul><ul><li>MOTOR NEURON INDUCED CONTRACTIONS OF SKELETAL MUSCLES AT BASE OF PENIS EXPELL THE SEMEN DURING EXPULSION PHASE OF EJACULATION </li></ul><ul><li>EJACULATION IS A PART OF ORGASM </li></ul>
    27. 27. FEMALE ORGASM <ul><li>PARALLELS THAT IN MALES WITH TWO EXCEPTIONS </li></ul><ul><li>NO COUNTERPART TO EJACULATION </li></ul><ul><li>NO REFRACTORY PERIOD-MULTIPLE ORGASMS POSSIBLE </li></ul>
    28. 28. Mechanism and Effects of Testosterone Activity <ul><li>Testosterone is synthesized from cholesterol </li></ul><ul><li>It must be transformed to exert its effects on some target cells </li></ul><ul><ul><li>Prostate – it is converted into dihydrotestosterone (DHT) before it can bind within the nucleus </li></ul></ul><ul><li>Testosterone targets all accessory organs and its deficiency causes these organs to atrophy </li></ul>
    29. 29. TESTOSTERONE: AT PUBERTY <ul><li>spermatogenesis </li></ul><ul><li>accessory sex glands enlarge and become secretory </li></ul><ul><li>penis and scrotum enlarge </li></ul><ul><li>libido </li></ul>
    30. 30. Other Physiological effects of testosterone <ul><li>Decreases GnRH secretion via the hypothalamus </li></ul><ul><li>Inhibits LH secretion on the anterior pituitary </li></ul><ul><li>Induces and maintains differentiation of male accessory sex glands and maintaining their function </li></ul><ul><li>Induces male secondary sexual characteristics </li></ul><ul><li>Stimulates protein anabolism, bone growth, and cessation of bone growth </li></ul><ul><li>Maintains sex drive and aggressive behaviour </li></ul>
    31. 31. Testosterone vs DHT <ul><li>Testosterone receptor complexes responsible for maturation of the wolffian duct structures – male internal genitalia </li></ul><ul><li>DHT receptor complexes resposible for male external genitalia </li></ul><ul><li>DHT at puberty: prostate enlargement, facial hair, temporal recession of hair, acne </li></ul><ul><li>Testosterone at puberty: increase in muscle mass, male sex drive </li></ul><ul><li>Congenital 5 α -reductase deficiency: male pseudohermaphroditism </li></ul><ul><li>Male internal genitalia including testis </li></ul><ul><li>Female external genitalia – raised as girls </li></ul><ul><li>At puberty increased testosterone: male body features,libido </li></ul><ul><li>Clitoris enlarges – “penis at 12 syndrome” </li></ul>
    32. 32. Male secondary sexual characteristics <ul><li>External genitalia </li></ul><ul><ul><li>Penis increases in size </li></ul></ul><ul><ul><li>Scrotum becomes pigmented and rugose </li></ul></ul><ul><ul><li>Internal genitalia </li></ul></ul><ul><ul><li>Seminal vesicles enlarge. </li></ul></ul><ul><ul><li>Prostate and seminal vesicles enlarge </li></ul></ul><ul><ul><li>Voice </li></ul></ul><ul><ul><li>Larynx enlarges, vocal cords increase in length and thickness – voice becomes deeper </li></ul></ul><ul><ul><li>Hair Growth </li></ul></ul><ul><ul><li>Beard appears. Hairline to scalp recedes. </li></ul></ul><ul><ul><li>Pubic hair grows with male pattern </li></ul></ul><ul><ul><li>Hair in axilla, on chest and around anus </li></ul></ul><ul><li>Mental </li></ul><ul><li>More aggressive </li></ul><ul><li>Active attitude </li></ul><ul><li>Interested in oppossite sex </li></ul><ul><li>Body conformation </li></ul><ul><li>Broad shoulders </li></ul><ul><li>Enlarging muslces </li></ul><ul><li>Skin </li></ul><ul><li>Sebaceous gland secretion thickens and increases (predisposing to acne) </li></ul>
    33. 33. Pathophysiology <ul><li>Cryptochidism </li></ul><ul><li>Undescended testes from the abdomen </li></ul><ul><li>Testicular descent depends on MIS </li></ul><ul><li>Higher incidence of malignancy </li></ul><ul><li>Infertility eventually </li></ul><ul><li>Hypogonadism </li></ul><ul><li>Clinical picture depends on onset </li></ul><ul><li>Before puberty </li></ul><ul><li>Picture of eunuchoidism </li></ul><ul><li>Tall- epiphysis remains open </li></ul><ul><li>Narrow shoulders and small muscles </li></ul><ul><li>Female body configuration </li></ul><ul><li>Small genitalia, high pitched voice </li></ul><ul><li>Pubic hair female pattern </li></ul><ul><li>In adulthood </li></ul><ul><li>Secondary sexual characteristics regress slowly </li></ul><ul><li>Hot flashes </li></ul><ul><li>More irritable, passive and depressed. </li></ul>
    34. 34. Brain-Testicular Axis <ul><li>Hormonal regulation of spermatogenesis and testicular androgen production involving the hypothalamus, anterior pituitary gland, and the testes </li></ul>
    35. 35. Brain-Testicular Axis <ul><li>Testicular regulation involves three sets of hormones: </li></ul><ul><ul><li>GnRH, which indirectly stimulates the testes through: </li></ul></ul><ul><ul><ul><li>Follicle-stimulating hormone (FSH) </li></ul></ul></ul><ul><ul><ul><li>Luteinizing hormone (LH) </li></ul></ul></ul><ul><ul><li>Gonadotropins, which directly stimulate the testes </li></ul></ul><ul><ul><li>Testicular hormones, which exert negative feedback controls </li></ul></ul>
    36. 36. Hormonal Regulation of Testicular Function <ul><li>The hypothalamus releases (GnRH) </li></ul><ul><li>GnRH stimulates the anterior pituitary to secrete FSH and LH </li></ul><ul><ul><li>FSH causes Sertoli cells to release androgen-binding protein (ABP) and inhibin </li></ul></ul><ul><ul><li>LH tropic for Leydig cells stimulates interstitial cells to release testosterone </li></ul></ul><ul><li>ABP binding of testosterone enhances spermatogenesis </li></ul>
    37. 37. CONTROL OF TESTICULAR FUNCTION HYPOTHALAMUS ANTERIOR PITUITARY GnRH + TESTES SERTOLI CELL LEYDIG CELL TESTOSTERONE INHIBIN SPERMATOGENESIS FSH LH local - - - Rhythmic release of GnRH from the hypothalamus initiated at puberty
    38. 38. Hormonal Regulation of Testicular Function <ul><li>Feedback inhibition on the hypothalamus and pituitary results from: </li></ul><ul><ul><li>Rising levels of testosterone (suggested for the male pill) </li></ul></ul><ul><ul><li>Increased inhibin </li></ul></ul>Figure 26.10
    39. 39. ANATOMY OF THE FEMALE REPRODUCTIVE SYSTEM <ul><li>vagina </li></ul><ul><li>uterus </li></ul><ul><li>cervix </li></ul><ul><li>clitoris </li></ul><ul><li>labia </li></ul><ul><li>ovaries </li></ul><ul><li>oviducts </li></ul>
    40. 40. Vagina Figure 26.16
    41. 41. UTERUS <ul><li>maintains fetus during pregnancy </li></ul><ul><li>musculature contracts to expel fetus at birth </li></ul>
    42. 42. CERVIX <ul><li>lowest portion of the uterus </li></ul><ul><li>projects into vagina </li></ul><ul><li>cervical canal serves as pathway for sperm during sexual intercourse </li></ul><ul><li>passagway for delivery of baby from uterus </li></ul>
    43. 43. CLITORIS <ul><li>erectile tissue analogous to penis in male </li></ul><ul><li>sensitive and erotic </li></ul><ul><li>at fold of labia minora </li></ul>
    44. 44. LABIA <ul><li>skin folds </li></ul><ul><li>majora- outer </li></ul><ul><li>minora-inner </li></ul><ul><li>around vaginal and urethral openings </li></ul>
    45. 45. External Genitalia <ul><li>Lies external to the vagina and includes the mons pubis, labia, clitoris, and vestibular structures </li></ul><ul><li>Mons pubis – round, fatty area overlying the pubic symphysis </li></ul><ul><li>Labia majora – elongated, hair-covered, fatty skin folds homologous to the male scrotum </li></ul><ul><li>Labia minora – hair-free skin folds lying within the labia majora; homologous to the ventral penis </li></ul>
    46. 46. OVARIES <ul><li>female gonads </li></ul><ul><li>in abdomen </li></ul><ul><li>produce ova </li></ul><ul><li>secrete estrogen and progesterone </li></ul>
    47. 47. The Ovaries Figure 26.14a
    48. 48. OVIDUCTS <ul><li>link ovaries to uterus </li></ul><ul><li>fallopian or uterine tubes </li></ul><ul><li>pick up ova at ovulation </li></ul><ul><li>site for fertilization </li></ul>
    49. 49. Female reproductive system <ul><li>Oogenesis During embryonic development oogonia divide by mitosis and form primary oocytes. By birth, oogonia are no longer present and the ovary contains its full complement of primary oocytes (about 2 million in humans of which only about 400-500 will be released). </li></ul><ul><li>Primary oocytes are in an arrested stage of prophase I of meiosis. </li></ul><ul><li>Beginning at puberty a small number of primary oocytes begin development each month (ovarian cycle). </li></ul><ul><li>. </li></ul>In humans normally only one oocyte from one of two ovaries will continue meiosis. Meiosis II is only completed after sperm penetration! Mechanism for choosing one to development is not understood. Oocytes in the ovary exist as follicles
    50. 50. Follicle growth <ul><li>Begins as primordial follicles – one primary oocyte + single layer of granulosa cells </li></ul><ul><li>Proliferation of granulosa cells, separation of oocyte – zona pellucida </li></ul><ul><li>Granulosa cells – oestrogen & little progesterone </li></ul><ul><li>Connective tissue cells around granulosa cells differentiate – forming layers theca </li></ul><ul><li>Antrum fluid-filled space forms: mature follicle </li></ul><ul><li>Beginning of cycle 10-25 follicles into antral follicles </li></ul><ul><li>Only one follicle – dominant follicle </li></ul>
    51. 51. Ovarian Cycle <ul><li>Female reproductive system shows regular cyclic changes. </li></ul><ul><li>Length variable between women average 28 days from the start of one cycle to the start of the next. </li></ul><ul><li>Follicular phase – period of follicle growth (days 1–14) </li></ul><ul><li>Luteal phase – period of corpus luteum activity (days 14–28) </li></ul><ul><li>Ovulation occurs midcycle </li></ul>
    52. 52. Follicular Phase <ul><li>10-12 primary follicles develop into antral folllicles </li></ul><ul><li>Day 6 one follicle becomes dominant follicle </li></ul><ul><li>Selection of dominant follicle not clear (oestrogen receptors) </li></ul><ul><li>Rest – atretic follicles </li></ul><ul><li>Primary follicle becomes a secondary follicle </li></ul><ul><ul><li>The theca folliculi and granulosa cells cooperate to produce estrogens </li></ul></ul><ul><ul><li>Theca interna primary source of circulating oestrogens </li></ul></ul><ul><ul><li>Folllicular fluid oestrogen from granulosa cells </li></ul></ul><ul><li>Day 14 distended follicle ruptures – ovum extruded into abdominal cavity – ovulation </li></ul><ul><li>Ruptured follicle fills with blood – corpus haemorrhagicum </li></ul><ul><li>Minor bleeding into abdomen – peritoneal irritation – lower abdominal pain “mittelschmerz” </li></ul><ul><li>1-2% of ovulations release more than one secondary oocyte, which if fertilized, results in fraternal twins </li></ul>
    53. 53. Follicular Phase Figure 26.20
    54. 54. Luteal Phase <ul><li>After ovulation, the ruptured follicle collapses, granulosa cells enlarge, and along with internal thecal cells, form the corpus luteum </li></ul><ul><li>The corpus luteum secretes progesterone and estrogen </li></ul><ul><li>If pregnancy does not occur, the corpus luteum degenerates in 10 days (4 days before menses), forming scar tissue (corpus albicans) </li></ul><ul><li>If pregnancy does occur, the corpus luteum produces hormones until the placenta takes over that role (at about 3 months) </li></ul>
    55. 55. Establishing the Ovarian Cycle <ul><li>During childhood, ovaries grow and secrete small amounts of estrogens that inhibit the hypothalamic release of GnRH </li></ul><ul><li>As puberty nears, GnRH is released; FSH and LH are released by the pituitary, which act on the ovaries </li></ul><ul><li>These events continue until an adult cyclic pattern is achieved and menarche occurs </li></ul>
    56. 56. Uterine (Menstrual) Cycle <ul><li>Series of cyclic changes that the uterine endometrium goes through each month in response to ovarian hormones in the blood </li></ul><ul><li>Days 1-5: Menstrual phase – uterus sheds all but the deepest part of the endometrium </li></ul><ul><li>Days 6-14: Proliferative phase – endometrium rebuilds itself. Uerine glands lenthen, are non secretory. </li></ul><ul><li>Days 15-28: Secretory phase – Endometrium becomes highly vascularised, slighty oedematous. Glands are coiled, tortuos, secreting a clear fluid. prepares for implantation of the embryo </li></ul><ul><li>Corpus luteum regression, hormonal support for endometrium is withdrawn. Endometrium becomes thinner </li></ul><ul><li>Foci of necrosis coalesce – haemorhage menstrual cycle </li></ul><ul><li>Length of secretory phase – very constant 14 days </li></ul>
    57. 57. Menses <ul><li>Normal menstruation 3-5 days. </li></ul><ul><li>Average blood flow 30ml </li></ul><ul><li>Flow affected by number of factors: endometrial thickness, medication, clotting diseases </li></ul>
    58. 58. Gonadotropins, Hormones, and the Ovarian and Uterine Cycles Figure 26.22a, b
    59. 59. Hormonal control of the mensrual cycle <ul><li>Control of Ovarian function </li></ul><ul><ul><li>Regulated by GnRH, FSH, LH, gonadal sex hormones estrogen, progesterone </li></ul></ul><ul><ul><li>FSH slight rise in follicular phase: stimulates granulosa cells to multiply and produce oestrogen </li></ul></ul><ul><ul><li>Oestrogen autocrine and hormonal effect </li></ul></ul><ul><ul><li>Autocrine further stimulates granulosa cell prolliferatiion </li></ul></ul><ul><ul><li>Androgens precursor to oestrogen production in granulosa cells. Theca cells synthesize androgens </li></ul></ul><ul><ul><li>LH acts on theca cells to proliferate and syntesize oestrogens] </li></ul></ul><ul><ul><li>Plasma concentrations of oestrogen increase with dominant follicle </li></ul></ul><ul><li>FSH levels begin to fall as a result of the steady rise of oestrogen in the later stage of the follicular phase </li></ul><ul><li>Inhibin from granulosa also has negative feedback effect on FSH secretion on the anterior pituitary </li></ul><ul><li>Negative feedback effect occurs in relatively low plasma concentrations </li></ul><ul><li>High oestrogen concentrations in late follicular phase enhnce sensitivity of LH release mechanisms. Positive feedback </li></ul><ul><li>Stimulates LH surge </li></ul><ul><li>LH surge stimulates ovulation </li></ul><ul><li>LH receptors on granulosa cells increase due to FSH and oestrogen on the granulosa cells. </li></ul><ul><li>LH surge stimulates transformation of theca cells and granulosa cells into corpus luteum </li></ul>
    60. 60. Effects of LH surge <ul><li>Oocyte is induced to complete its first meiotic division </li></ul><ul><li>Antrum size and blood flow increase </li></ul><ul><li>Granulosa cells begin producing progesterone </li></ul><ul><li>Enzymes and prostaglandins breakdown the follicular-ovarian membranes </li></ul><ul><li>Granulosa and theca cells transformed into corpus luteum </li></ul>
    61. 61. Corpus luteum Hormonal Activity <ul><li>Secretes large quantities of progesterone and oestrogen </li></ul><ul><li>In presence of oestrogen, progesterone acts on the hypothalamus to suppress GnRH secretion </li></ul><ul><li>Inhibin further inhibits FSH secretion </li></ul><ul><li>Degeneration of corpus luteum plasma oestrogen and progesteron decrease </li></ul>
    62. 62. Hormonal control of uterine changes <ul><li>Proliferative phase: rising oesrogen stimulates growth of endometrium and myometrium </li></ul><ul><li>Induces synthesis of progesterone receptors on endometrial cells </li></ul><ul><li>Secretory phase: progesterone converts endometrium to seccreting tissue </li></ul><ul><li>Progesterone inhibits myometrial contraction </li></ul>
    63. 63. Cyclic changes in Uterine cervix <ul><li>Oestrogen makes cervical mucus thinner, more alkaline – promote survival and transport of sperm </li></ul><ul><li>Mucus thinnest at ovulation, more elastic </li></ul><ul><li>After ovulation & during pregnancy thick, does not form fern pattern </li></ul>
    64. 64. Vaginal cycle <ul><li>Oestrogen – vaginal epithelium cornified, </li></ul><ul><li>Progesterone – thick mucus secreted, epithelium infiltrated by leucocytes </li></ul>
    65. 65. Gonadotropins, Hormones, and the Ovarian and Uterine Cycles Figure 26.22c ,d
    66. 66. <ul><li>Estrogen levels rise during puberty </li></ul><ul><ul><li>Promote oogenesis and follicle growth in the ovary </li></ul></ul><ul><ul><li>Exert anabolic effects on the female reproductive tract </li></ul></ul><ul><ul><ul><li>Uterine tubes, uterus, and vagina grow larger and become functional </li></ul></ul></ul><ul><ul><ul><li>Uterine tubes and uterus exhibit enhanced motility </li></ul></ul></ul><ul><ul><ul><li>Vaginal mucosa thickens and external genitalia mature </li></ul></ul></ul>Extrauterine Effects of Estrogens and Progesterone
    67. 67. <ul><li>Growth of the breasts </li></ul><ul><li>Increased deposition of subcutaneous fat, especially in the hips and breasts </li></ul><ul><li>Widening and lightening of the pelvis </li></ul><ul><li>Growth of axillary and pubic hair </li></ul>Estrogen-Induced Secondary Sex Characteristics
    68. 68. Cyclic changes in Breast <ul><li>Oestrogens : proliferation of mammary ducts </li></ul><ul><li>Progesterone : growth of lobules and alveoli </li></ul>
    69. 69. Indicators of ovulation <ul><li>Secretory pattern indicative of functional corpus luteum </li></ul><ul><li>Rise in basal temperature due to increase in progesterone (thermogenic) </li></ul>
    70. 70. CONTROL OF FSH AND LH SECRETION DURING FOLLICULAR PHASE HYPOTHALAMUS ANTERIOR PITUITARY GRH + OVARY LOW LEVELS OF ESTROGEN INHIBIN FSH LH
    71. 71. CONTROL OF LH SURGE AT OVULATION HYPOTHALAMUS ANTERIOR PITUITARY GNRH + OVARY HIGH LEVELS OF ESTROGEN OVULATION FSH LH MATURE FOLLICLE
    72. 72. FEEDBACK CONTROL DURING LUTEAL PHASE HYPOTHALAMUS ANTERIOR PITUITARY GNRH + OVARY HIGH LEVELS OF PROGESTERONE LH CORPUS LUTEUM MODERATE LEVELS OF ESTROGEN
    73. 73. Oestrogen functions <ul><li>Stimulates growth of ovary and follicles </li></ul><ul><li>Stimulates growth of smooth muscle and proliferation of epithelial lining of genital tract </li></ul><ul><li>Uterine tubes: increases contractions and ciliary activity </li></ul><ul><li>Uterus: increases myometrial contractions and responsiveness to oxytocin. Induces progesterone receptors </li></ul><ul><li>Stimulates external genitalia growth </li></ul><ul><li>Stimulates female body configuration </li></ul><ul><li>“ antiacne” effect </li></ul><ul><li>Female secondary sexual characteristics </li></ul><ul><li>Fluid retention </li></ul><ul><li>Stimulates prolactin secretion but inhibits prolactin’s milk – inducing effect on the breasts </li></ul>
    74. 74. Progesterone effects <ul><li>Stimulates endometrial glands to secrete </li></ul><ul><li>Induces thick, sticky cervical mucus </li></ul><ul><li>Decreases contractions of uterine tubes and myometrium </li></ul><ul><li>Stimulates breast growth </li></ul><ul><li>Feedback effect on the hypothalamus and pituitary </li></ul>
    75. 75. FERTILIZATION <ul><li>in oviduct </li></ul><ul><li>sperm deposited in vagina at ejaculation </li></ul><ul><li>travel to oviduct takes a little over 1/2 hour </li></ul><ul><li>cervical canal is open due to estrogen being high and remains open two to three days </li></ul><ul><li>sperm enter uterus and are churned around </li></ul><ul><li>when reach oviduct, smooth muscle contractions propel them onward </li></ul><ul><li>mature egg releases a chemotactic agent attracts sperm </li></ul><ul><li>out of several hundred million only a few thousand make it </li></ul><ul><li>tail of sperm maneuvers it for final penetration </li></ul>
    76. 76. HORMONES OF PREGNANCY <ul><li>placenta is organ of exchange </li></ul><ul><li>placenta secretes human chorionic gonadotropin (hcg)-prolongs life of corpus luteum </li></ul><ul><li>estrogen and progesterone levels even higher now </li></ul><ul><li>Relaxin – inhibits uterine contractions </li></ul><ul><li>after 6 weeks placenta takes over from the corpus luteum I producing oestrogen and progesterone </li></ul><ul><li>hCG α and β units. α unit is identical to α units of LH, FSH and TSH. </li></ul><ul><li>hCG is primarily lutenising with little FSH activity </li></ul><ul><li>Detected in blood 6 days after conception </li></ul><ul><li>Detected in urine 14 days after conception </li></ul><ul><li>Feto-placental unit: fetus and placenta interact to formsteroid hormones </li></ul>
    77. 77. PARTURITION <ul><li>Pregnacy duration averages 40 weeks from last menstrual period </li></ul><ul><li>Oxytocin receptors on uterus proliferate </li></ul><ul><li>positive feedback </li></ul><ul><li>cervical dilation </li></ul><ul><li>delivery </li></ul><ul><li>delivery of placenta </li></ul>
    78. 78. LACTATION <ul><li>mammary glands or breasts </li></ul><ul><li>milk producing glands and fat </li></ul><ul><li>action of estrogen and progesterone is to prepare glands during pregnancy </li></ul><ul><li>also block prolactin’s stimulation </li></ul><ul><li>oxytocin-milk ejection </li></ul><ul><li>suckling triggers oxytocin release </li></ul>
    79. 79. Mammary Glands <ul><li>Modified sweat glands consisting of 15-25 lobes that radiate around and open at the nipple </li></ul><ul><li>Areola – pigmented skin surrounding the nipple </li></ul><ul><li>Lobes contain glandular alveoli that produce milk in lactating women </li></ul><ul><li>Compound alveolar glands pass milk to lactiferous ducts, which open to the outside </li></ul>
    80. 80. Breast Cancer <ul><li>Usually arises from the epithelial cells of the ducts </li></ul><ul><li>Risk factors include: </li></ul><ul><ul><li>Early onset of menses or late menopause </li></ul></ul><ul><ul><li>No pregnancies or the first pregnancy late in life </li></ul></ul><ul><ul><li>Previous history of breast cancer or family history of breast cancer </li></ul></ul><ul><ul><li>Hereditary factors such as mutations to a pair of genes BRCA1 and BRCA2 </li></ul></ul><ul><li>70% of women with breast cancer had no known risk factors </li></ul>
    81. 81. Breast Cancer: Detection and Treatment <ul><li>Early detection is by self-examination and mammography </li></ul><ul><li>Treatment depends upon the characteristics of the lesion </li></ul><ul><li>Radiation, chemotherapy, and surgery followed by irradiation and chemotherapy </li></ul><ul><li>Today, lumpectomy is the surgery used rather than radical mastectomy </li></ul>
    82. 82. contraception <ul><li>Hormonal </li></ul><ul><li>Steriliztion and abortion </li></ul><ul><li>Barrier methods </li></ul><ul><li>Natural family planning </li></ul>
    83. 83. hormonal <ul><li>Progesterone Only Method </li></ul><ul><li>Mini Pills …prevents ovulation/hampers sperm motility and also prevents the necessary monthly enrichment of the uterine lining </li></ul><ul><li>Oral Contraceptive Pills </li></ul><ul><li>Hormonal Patches (Erva) (a favorite of teenagers!) </li></ul><ul><li>Injection (Lunelle) </li></ul><ul><li>Vaginal ring </li></ul>
    84. 84. hormonal <ul><li>Depo-Provera, a progesterone available in many countries, is administered by injection once every three months. </li></ul><ul><li>Depomedroxyprogesterone Acetate </li></ul>
    85. 85. <ul><li>Norplant consists of a set of small, soft tubes that are surgically implanted under the skin of a woman's arm, where they release the synthetic hormone progestin, which can prevent conception for up to five years </li></ul>
    86. 86. hormonal <ul><li>The &quot;morning-after pill&quot;--a series of pills containing either high dosages of both estrogen and progestogen (any progestational steroid, such as progesterone) or only progestogen--is one of the few methods for preventing pregnancy after intercourse </li></ul>
    87. 87. <ul><li>combination of synthetic estrogen and synthetic progesterone, which inhibit ovulation by simulating the biochemical action by which ovulation is arrested during pregnancy </li></ul>
    88. 88. Abortion/Sterilization <ul><li>vasectomy--the blocking or severing of the ductus deferentes (or vasa deferentia </li></ul><ul><li>in females sterilization results from tubal ligation--the blocking or severing of the fallopian tubes </li></ul>
    89. 89. Barrier methods <ul><li>Diaphrams </li></ul><ul><li>Condoms </li></ul><ul><li>Spermacidals </li></ul><ul><li>Cervical Cap </li></ul>
    90. 90. BARRIER METHODS CONT. <ul><li>Intrauterine Devices: plastic or metal objects in a variety of shapes that are implanted inside the uterus </li></ul>
    91. 91. Natural family planning <ul><li>Abstinence (100% effective!!!!!!) </li></ul><ul><li>Withdrawal </li></ul><ul><li>Fertility Awareness Methods </li></ul><ul><li>Lactation Amenorrhea Method </li></ul><ul><li>Outercourse </li></ul>
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