Female Reproductive System

Dr Asma Jabeen

Learning Objectives

By the end of lecture, the students will be able to:

• Describe the physiologic anatomy of the female female reproductive system

• Describe the female hormonal system• Discuss the functions of female reproductive

hormones• Discuss the steps of oogenesis.

PHYSIOLOGIC ANATOMY OF THE

FEMALE SEXUAL ORGANS

FEMALE HORMONAL SYSTEM

1. Gonadotropin- releasing hormone

(GnRH) released from hypothalamus

2. FSH and LH secreted in response to GnRH from anterior pituitary

3. Estrogens and Progesterone secreted from the ovaries

Gonadotropin releasing hormone (GnRH)

➢ decapeptide➢Release primarily in the mediobasal

hypothalamus, especially in arcuate nuclei. ➢ Some from preoptic nucleus of anterior

hypothalamus.➢ released in pulses lasting 5-25min every

1-2 hrs

ESTROGENS

Secretion:Non-pregnant female → Secreted mainlyfrom granulosa cells of ovaries, corpusluteum and minute amounts secreted by adrenal cortices

Pregnant female → Tremendous quantitiessecreted by placenta along with ovaries

• ß-estradiol• Estrone• Estriol

Types:

Synthesis:➢ Synthesized in ovaries mainly from

cholesterol but to a less extent from acetyl-Coenzyme A.➢ Synthesis depends upon enzyme

AROMATASE.

Production of estrogen by granulosa cellsUnder the effect of FSH & LH

Transport:➢ Both estrogens and progesterone are

transported mainly bound to plasma albumin and globulins.➢ 2% of estradiol and progesterone is free,

rest is bound to protein. ➢ Binding is loose so that hormones are

released to tissues over a period of 30 min .

Estrogen Degradation:▪ The liver conjugates the estrogen to form glucuronides and sulphates

• 1/5th of it excreted in bile• Remainder excreted in urine▪ Liver also converts potent estrogen to totally impotent estrogen, estriol.

Hyperestrinism occurs in liver failure

causing increase in activity of estrogens

in the body.

Functions of Estrogens

Primary function is to cause cellularproliferation and growth of the tissues of Sex organs

and tissues related to reproduction .

Effect on uterus and external sex organs:➢ level increases 20 folds at puberty (GnRH)➢ Ovaries, fallopian tubes ,uterus and vagina increase several times in size

➢ Vagina → Epithelium changes from cuboidal to stratified type → increasedresistance

Uterus → marked proliferation of endometrial stroma, greatly increased development of endometrial glands → to provide nutrition to implanted ovum ▪ Estrogen increase uterine muscle and its content of contractile proteins.▪ Muscle becomes more active and excitable → ↑ frequency of AP

Effect on Fallopian tubes:

➢ The glandular tissues of mucosal lining proliferate➢ The number of ciliated epithelial cells increase➢ The activity of cilia is enhanced

Effect on the Breasts:➢ Development of stromal tissues of breasts➢ Growth of an extensive ductile system➢ Deposition of fats

Effect on the Skeleton:➢ Stimulation of Osteoprotegerin –

osteoclastogenesis inhibitory factorInhibition of osteoclastic activity → stimulating bone growth → rapid increase in height for several years after puberty➢ Uniting of epiphyses with shafts of long

bones

Osteoporosis of bones caused by EstrogenDeficiency in old age:

▪ Increased osteoclastic activity in bones▪ Decreased bone matrix▪ Decreased deposition of calcium and

phosphate ↓

Osteoporosis with weakness and fractures of bones

Effect on Protein deposition:Estrogen causes▪ Increased protein deposition▪ Positive nitrogen balance▪ Growth promoting effects on sexual organs, bones and few other tissues

Effect on body metabolism :Estrogen increases the whole body

metabolic rate (1/3rd as much as male sexhormone)

Effect on Fat deposition:Causes increased fat deposition →Characteristic

female contour

Effect on hair distribution:No great effect on hair distribution

but hair growth occur in pubic and axillary regions after puberty.

Effect on Skin: ➢ Soft and smooth skin➢ ↑ vascular skin → ↑warmth,↑ bleeding

from cut surface

Effect on Electrolyte balance:

▪ Chemically similar to adrenocortical hormones▪ Cause sodium and water retention

specially in pregnancy

Effect on blood cholesterol:Estrogens have significant plasma

cholesterol lowering action.

Progesterone

❑ In normal non-pregnant female ,secreted in significant amounts only during the later half of ovarian cycle by corpus luteum

❑ Large amounts are secreted from Placenta in pregnancy, starting from 4th month.

Functions of Progesterone

Effect on the Uterus:❑ Promote secretory changes in the uterine

endometrium during the later half of the monthly female sexual cycle, preparing it for implantation.

❑ It decreases the frequency and intensityof uterine contractions.

Effect on the Fallopian tubes:

It increases the secretions by the mucosal lining of the fallopian tubes, necessary for nutrition of the fertilized, dividing ovum as it traverses the tubes before implantation.

Effect on Breasts:

❑ Progesterone promotes the developmentof the lobules and alveoli of the breast.alveoli become enlarged ,secretory .

❑ Cause increased fluid in subcutaneous tissue → swelling of breast

Relaxin:

It is a polypeptide hormone produced inthe corpus luteum, uterus, placenta and mammary glands in women and in prostate gland in men.

Functions:

▪ In non-pregnant woman, it is found in corpus luteum and endometrium in secretory phase. Function not known.

▪ In pregnant woman, it relaxes the pubic symphysis and other pelvic joints.▪ It softens and dilates the uterine cervix thus facilitates delivery.▪ It inhibits uterine contractions and play role in development of mammary glands.▪ In men, found in semen, helps maintain sperm motility and helps in penetration of ovum.

Oogenesis

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