Female reproductive system

1. FEMALE REPRODUCTIVE SYSTEM

2. PRINCIPAL ORGANS
• Ovaries
• Fallopian tubes (also called uterine tubes),
• Uterus
• Cervix
• Vagina

3. OVARIES
• Gonad or primary sex organs in females
• A pair of ovaries- normally present
• Two functions of ovary
Gametogenic
Endocrine functions
• Gametogenic function-
Production and release of ovum or egg
• Endocrine function-
Secretion of female sex hormones

4. OVARIAN FOLLICLE

5. OVARIAN HORMONES
• Ovary secretes the female sex hormones
Estrogen
Progesterone
• Ovary also secretes few more hormones
Inhibin
Relaxin
Small quantities of androgens.

6. ESTROGEN
Source of Secretion
• Normal non-pregnant woman
Large quantity- theca interna cells of ovarian follicles
Small quantity- corpus luteum of the ovaries
• Predominant in later stage of follicular phase before ovulation
• Derived from androgens- androstenedione
• Secreted in theca interna cells

7. • Androstenedione migrates from theca cells to granulosa cells, where it is converted into
estrogen by the activity of the enzyme aromatase.

8. • A small quantity of estrogen is also secreted by adrenal cortex.

9. • In pregnant woman, a large amount of estrogen is secreted by the placenta.

10. CHEMISTRY
• Estrogen is a C18 steroid
• Estrogen is present in three forms in plasma:
β-estradiol
Estrone
Estriol
• The quantity and potency of β-estradiol are more than those of estrone and estriol.
• Plasma Level- varies during different phases of menstrual cycle.
Follicular phase- 30 to 200 pg/mL
• Half-life of estrogen- 30 to 60 minutes.

11. SYNTHESIS
• Estrogen are synthesized from- cholesterol or acetate
• Acetate - converted into cholesterol
• Pathway for synthesis of estrogen

12. TRANSPORT IN PLASMA
• Estrogen is transported mainly by albumin
• Small quantity by globulin
• The binding of estrogen with the plasma protein is loose, so that the
hormones are released into the tissues easily

13. METABOLISM
• Estrogen is degraded mainly in the liver.
• Conjugated with glucuronides and sulfates.
• One fifth of the conjugated products
are excreted in the bile.
• Remaining part is excreted in the urine.

14. FUNCTIONS OF ESTROGEN
• Major function:-
To promote cellular proliferation and tissue growth in the sexual organs
• Childhood- secretion in small quantity.
• Puberty- secretion increases sharply

15. Effects of estrogen are:
1. Effect on Ovarian Follicles
Promotes the growth of ovarian follicles
By increasing the proliferation of the follicular cells
It also increases the secretoryactivity of theca cells

16. EFFECT ON UTERUS
• Proliferation of endometrial cells - Enlargement of uterus
• Increase blood supply to endometrium
• Deposition of glycogen and fats in endometrium
• Proliferation and dilatation of the endometrial glands- more tortuous
• Increase in the spontaneous activity and contractility of uterine muscles
All these changes prepare uterus for pregnancy.

17. EFFECT ON FALLOPIAN TUBES
i. Mucosal lining
Increases the number and size of the epithelial cells (ciliated epithelial cells)
ii. Cilia
Increases the activity
Movement of ovum is facilitated
iii. Glands
Enhances the proliferation
• Necessary for the fertilization of ovum.

19. EFFECT ON VAGINA
• Changes the vaginal epithelium:-
i. Cuboidal into stratified type
Stratified epithelium is more resistant to trauma and infection
ii. Proliferation of layers of vaginal epithelium
iii. Reduces the pH of vagina, making it more acidic
Necessary for the prevention of infection

20. EFFECT ON SECONDARY SEXUAL CHARACTERS
• Development of secondary sexual characters- estrogen necessary
• Secondary sexual characters in female
i. Hair distribution:
Pubic region and axilla
Female pubic hair- base of the triangle upwards
Body hair growth- less
Scalp hair grows profusely
ii. Skin:
Skin becomes soft and smooth.
Vascularity of skin also increases

21. iii. Body shape:
Shoulders become narrow
Hip broadens
Thighs converge
Arms diverge.
Fat deposition increases in breasts and buttocks

22. iv. Pelvis:
Broadening of pelvis with increased transverse diameter
Round or oval shape of pelvis
Round or oval shaped pelvic outlet.
v. Voice:
Larynx remains in prepubertal stage
Produces high-pitch voice.

23. EFFECT ON BREAST
Development of stromal tissues of breasts
Growth of an extensive ductile system
Deposition of fat in the ductile system
Development of lobules and alveoli of the breasts
Prepare the breasts for lactation

24. EFFECT ON BONES
Puberty
• Increases osteoblasticactivity.
• Growth rate increases enormously at puberty
• Early fusion of epiphysis with the shaft.
Old age
• Estrogen is not secreted or it becomes scanty.
• Leads to osteoporosis-bones become extremely weak and fragile.
• Highly susceptible for fractures

25. 8. Effect on Metabolism
On protein metabolism
Induces anabolism of proteins- increases the total body protein
On fat metabolism
Deposition of fat in the subcutaneoustissues, breasts, buttocks and thighs.
Overall specific gravity of the female body is considerably less
9. Effect on Electrolyte Balance
Sodium and water retention from the renal tubules.
Significant in pregnancy

26. MODE OF ACTION OF ESTROGEN
• Estrogen receptors situated on nuclear membrane of target cells
• Two types- α and β receptors.
α receptors- uterus, liver, heart and kidneys.
β receptors- ovaries
• Estrogen acts by activation of genes

27. REGULATION OF ESTROGEN
SECRETION-
HPO AXIS
• FSH is stimulated by the gonadotropin-releasing
hormone (GnRH)
• Follicle-stimulating hormone (FSH) from
pituitary
• Theca cells and granulosa cells have many FSH
receptors.
• FSH acts via cAMP and stimulates cells

28. • Estrogen inhibits secretion of FSH and GnRH by
negative feedback.
• Inhibin secreted by granulosa cells also decreases
estrogen secretion, by inhibiting the secretion
of FSH and GnRH

29. PROGESTERONE
Source of Secretion
• Non-pregnant woman
Small quantity secreted by theca interna
(follicular stage)
Large quantity secreted by the corpus luteum
(secretoryphase)
Small amount secreted from adrenal cortex too

30. • Pregnant woman
First trimester- large amount of progesterone is secreted by the corpus luteum
Second trimester- Corpus luteum degenerates.
- Placenta secretesprogesterone in second and third trimesters.

31. SYNTHESIS
• Synthesized in ovaries from:
Acetate
Cholesterol
• Plasma Level
Females (reproductive age)- varies during different phases of menstrual cycle
Follicular phase- 0.9 ng/mL
• Transport in Blood
Progesterone is transported by the plasma proteins – albumin and globulin.

32. METABOLISM
• Progesterone is degraded into another steroid- pregnanediol
• Do not have progesterone effect
• Degraded in liver
• Conjugated with glucuronic acid
• Excreted in the urine

33. FUNCTIONS OF PROGESTERONE
• Final preparation of:
Uterus for pregnancy
Breasts for lactation
• The effects are:
Fallopian Tubes
Increases secretory activities of mucosal lining
Necessary for nutrition of the fertilized ovum

34. 2. EFFECT ON THE UTERUS
• Promotes the secretory activities of endometrium during secretoryphase
• Prepares uterus for implantation
• Progesterone:
Increases the thicknessof endometrium
Thickness of endometrium
Increases from 1 mm thickness- beginning of secretory phase
5 to 6 mm - end of secretoryphase
Increases the size of uterine glands
Glands become more tortuous

35. • Secretory activities of uterine glands
• Increases the blood supply to endometrium
• Increase in size of the vessels and vasodilatation
• Decreases the frequency of uterine contractions
Prevention of expulsion of implanted ovum

36. 3. Effect on Cervix
Increases the thickness of cervical mucosa
Inhibits the transport of sperm into uterus
Physiological basis of contraceptive actions of minipills
4. Effect on the Mammary Glands
Promotes development of lobules and alveoli
Makes the breasts secretory

37. 5. Effect on Hypothalamus
Inhibits the release of LH from hypothalamus- feedback effect
Contraceptive action- physiological basis
6. Thermogenic Effect
Increases the body temperature after ovulation
Acts on hypothalamic temperature regulation centre
Physiological basis of increase in basal body temperature-
indication of ovulation

38. 7. Effect on Respiration
Luteal phase- progesterone increases the ventilation
Decreases the partial pressure of carbon dioxide in the alveoli
8. Effect on Electrolyte Balance
Increases the reabsorption of sodium and water

39. MODE OF ACTION OF PROGESTERONE
• Receptors situated on the nuclear membrane
• 2types:
A-progesterone receptors
B-progesterone receptors.
• Acts through genes

40. REGULATION OF PROGESTERONE SECRETION
GnRH- released from hypothalamus
LH from anterior pituitary
Corpus luteum to secrete progesterone
Progesterone inhibits the release of LH-
Negative feedback
HPO Axis