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Home , Endometrium, Follicular phase, Oogenesis

THE PHYSIOLOGY OF GENITAL SYSTEM

1 Susy Purnawati Learning Objectives

 Summarize the physiological, and hormonal aspects of the male and female reproductive cycles  Discuss the physiology of Two major phases of female reproductive functions:

1. Preparation of the female body to conception and 2. The period of pregnancy itself. The female hormonal system consists of three hierarchies of :

1. GnRH (Gonadotropin-Releasing , from hypothalamus) 2. FSH and LH (from ) 3. and (from the gonads- ovarium) The Pituitary-Gonad Axis Feedback Pathways  Trophic hormones: Follow the general pattern When circulating levels of gonadal are low, the pituitary secretes FSH and LH. Once streroid secretion reaches a certain level, negative feedback usually inhibits gonadotropin release. Feedback Pathways … (cont.)

 In contrast, estrogen alternates between positive and negative feedback.

 Lower concentrations of estrogen have a negative feedback effect. However, if estrogen rises rapidly to a threshold level or above for at least 36 hours, feedback changes from negative to positive, and gonadotropin release (particularly LH) is stimulated. Ovarian and endometrial cycle

The female reproductive (monthly) cycles: 1) Ovarian cycle

Three phases of ovarian cycle: 1. 2. 3. Lutheal phase

2) Uterine (endometrial) cycle: 1. Proliferative phase 2. Secretory phase 3. & Ovarian cycle

 Reproduction begins with the development of ova in the  About 7 million oogonia in embryonic develop into half a million primary  During fetal life, the outer surface of the ovary is covered by a germinal , primordial ova (a primary ), with a layer of granulosa cells = primordial follicle  During childhood, when almost no pituitary gonadotropic hormones are secreted, the ovaries remain inactive

 At the age of 9 to 12 years, the pituitary does begin to secrete progressively more FSH and LH =

 Which then leads to onset of monthly sexual cycles beginning (= ) between the ages of 11 and 15 years  Oöcytes ( cells) develop within follicles 1.Stages of follicular development  Primordial follicle  Single layer of squamous cells around the oöcyte  Primary follicle  Layers of cuboidal granulosa cells around the oöcyte  Granulosa cells secrete 1. The follicular phase (or the phase of follicular maturation)

 Rapid proliferation of the  Several layers outside the granulosa cells develop the theca  During the follicular phase, the follicle secrete hormones: estrogens (prepare the to receive the ). 2. The ovulation phase

 Ovulation occurs 14 days after the onset of menstruation

 The protruding outer wall of the follicle swells rapidly, than the stigma rupture

 During ovulation, the ovum is extruded from the follicle, whose wall breaks, and is aspirated into the  Secondary follicle  Antral cavity forms  Graafian follicle  Follicle mature ready to ovulate oöcyte  Ovulation  Follicle ruptures releasing oöcyte The ovulation phase

15 The ovulation phase

16 3. The lutheal phase (or preparation of the uterus for the potential implantation of an embryo)

 The follicle (the remaining granulosa and cells) is transformed into a corpus lutheum (lipid inclusion)

17  After ovulation, empty follicle becomes a corpus luteum  Corpus Luteum secretes:-  Progesterone – completes the preparation of uterine lining  Estrogens – work with progesterone  – relaxes uterine muscles and pubic symphysis  Inhibin – decreases secretion of FSH and LH  is a white tissue left after the corpus luteum dies.  2. Oogenesis: while in men happens in about a month, in oogenesis takes several years. During fetal development oocytes undergo I but do not completel it; at this point they are called primary oocytes. At ovulation the primary oocyte completes meiosis I and begins meiosis II which is completed only if fertilization occurs. At the completion of meiosis II the oocyte is called an ovum. The monthly endometrial cycle

1. Proliferative phase (estrogen phase)

 Occurring before ovulation  The stromal cells and the epithelial cells proliferated rapidly (the endometrial glands and new blood vessels) under influence of estrogen  The is 3 to 5 mm thick (at the time of ovulation)  Mucus secretion 20 2. Secretory phase (progestational phase)

 Occuring after ovulation  Progesteron and estrogen together are secreted in large quantity by the corpus lutheum  Swelling and secretory development of the endometrium  Endometrium is 5 to 6 mm thick (at the peak of the secretory phase)

21 3. Menstruation

 Estrogens and progesterons decrease to low levels of secretion  vasoplastic release vasoconstrictors materials () … necrotic of the endometrium  The menstrual fluid is normally noncloting … fibrinolysin

22 Summary of Ovarian and Menstrual Cycles Female Reproductive Physiology All together Secretory proliferasi

25 Functions of estrogens

Their effects on the primary and secondary female characteristics:

1. Uterus and external female  Change (ovaries, fallop. tube, uterus and ) from those a child to those of an adult  The ext. genitalia enlarge, with deposition of fat in the and majora and with enlargement of the .

2. Fallopian tubes

26 Functions of estrogens

2. Fallopian tubes Estrogen cause the glandular tissues in this lining to proliferate, cause the number and activity of ciliated epithelial cells to increase

27 Functions of estrogens

3. (1) Development of the stromal tissues of the breasts (2) Growth of an extensive ductile system, and (3) Deposition of fat in the breasts Do not complete the job of converting the breasts into milk producing organs

28 Functions of estrogens

4. Skin Cause the skin to develop a texture that is soft and usually smooth , become more vascular (increased warmth, greater bleeding)

5. Skeleton Increase osteoblastic activity in the bones (growth in height becomes rapid for several years Cause uniting of the epiphyses with the shafts of the long bones

29 Functions of estrogens

6. Protein deposition Cause a slight increase in total body protein

7. Body metabolism and fat deposition Cause deposition of increased quantities of fat in the subcutaneous tissues (buttocks and thighs, feminine figure)

30 Functions of estrogens

8. Hair distribution Estrogen do not greatly affect hair distribution (pubic region and in the axillae after puberty). are mainly responsible for this.

9. Electrolyte balance Cause sodium and water retention by the kidney tubules

31 Functions of progesterone  Their effect on: 1. Uterus  Promote endometrium to increase secretion  Decreases frequency and intensity of

2. Fallopian tubes 3. Breasts  Promotes development of the lobulus and alveoli of the  Promote breast to swell  But does not cause to secrete milk 4. Electrolyte balance

32 Adrenal androgens influence female secondary sex characteristics

Pubic and axillary (armpit) hair growth, and

(sex drive) Female sexual act

 Female sexual desire Is affected by estrogen levels and adrenal

 Similar with male sexual act.  Stimulation (psychic and local ) of the female sexual act  Erogenous zone

34 Female sexual act

 Stages are comparable to those of male sexual function  Arousal causes clitoral  Vaginal surfaces are moistened  Parasympathetic stimulation causes engorgement of blood vessels in the nipples Female sexual act

Female erection

Erectile tissue Parasimpathetic nerve (that pass through the nervi erigentes from sacral plexus to the external genitalia)

36

Female sexual act

Lubrication (by Bartholin) Parasympathetic signal also pass to the bilateral Bartholin’s glands located beneath the labia minora and cause them to secrete mucus immediately inside the introitus Is responsible for much of lubrication during sexual intercourse, to avoid irritation sensation 38 Female

When local sexual stimulation reaches maximum intensity, and supported by appropriate psychic conditioning (cerebrum reflex) During the orgasm, the perineal muscles contract rhytmicaly, which results from spinal cord reflexes.

39 Female orgasm  The walls of vagina and uterus contract  Seems to cause dilatation of (30’), allowing easy transport of the  The intense sexual sensations also pass to the cerebrum and cause intense muscle tension throughout the body, than resolution

40 One case

 Ni Nyoman Wartini, 25 y.o., unmarried, came to emergency room a private hospital at Ubud with her family with complain of nausea and vomiting. The doctor diagnose her with “observasi vomiting and moderate dehydration”. She was hospitalized with some medication for her vomiting symptom.

 Thinking, raise your opinion!  What is her problem???????

Fertilization Pregnancy: occurs once an egg is successfully fertilized and successfully implants. Fertilization

 Fertilization of an egg by sperm is the result of a chance encounter, possibly added by chemical attractants produced by the egg  An egg can be fertilize for only about 12-24 hours after ovulation. Sperm in the female reproductive tract remain viable for four to six days Fertilization

 If fertilization occurs:-  Embryo implants in endometrium  Must maintain levels of progesterone to maintain the endometrium and pregnancy  Since corpus luteum secretes progesterone, it must be maintained  LH normally maintains the corpus luteum, but LH is inhibited by high progesterone levels Implantation

Implantation of the into the uterine wall normally takes place about 7 days after fertilization As the blastocyst implants in the uterine wall and the begins to form Implantation

 The outer part of blastocyst (the ) secretes the hormone human chorionic gonadotropin (hCG)  hCG takes the place of LH and maintains the corpus luteum  After about 3-4 months of pregnancy, corpus luteum degenerates  Placenta now produces its estrogen and progesterone and maintains endometrium Estrogen and progesterone during pregnancy  Estrogen and progesterone are produced continuously during pregnancy, first by corpus luteum under influence of hCG (human chorionic gonadotropin) and then by the placenta  With high circulating level of these hormones, feedback suppression of the pituitary continuous through pregnancy, preventing another set of follicles from beginning development  Estrogent contributes to development of the milk-secreting ducts of the breasts  Progesterone is essential for maintaining the endometrium and suppress uterine contractions Signs of Pregnancy Signs of Pregnancy Signs of Pregnancy Signs of Pregnancy

Aging and the

Menopause

 The time that ovulation and menstruation cease  Typically around age 45-55  Accompanied by a decline in circulating estrogen and progesterone  Rise in GnRH, FSH, LH