Ovarian and Menstrual Cycle

Dr. Sadaf Mumtaz4/2/11

Physiological Anatomy

Female Reproductive Organs

Female Hormones

• GnRH

• LH

• FSH

• Estrogen

• Progesterone

Female monthly sexual cycle

• Duration

• Significance

• Difference in production of hormones between the two sexes

Oogenesis and spermatogeneis• Oogonia divide mitotically to give rise to

6-7 million oogonia by the fifth month of gestation when mitotic proliferation ceases.

• During the last part of fetal life, the oogonia begin the early steps of the first meiotic division but do not complete it. The primary oocytes stay in meiotic arrest for years until they are prepared for ovulation. Just before ovulation, the primary oocyte completes its first meiotic division.

• Recently it has been discovered that at least in mice, new oocytes and follicles are produced after birth from unknown ovarian stem cells

• Limited gamete potential in females (of the total pool of follicles only 400-500 will mature and release ova)

• In addition to providing half the genes, provides all the cytoplasmic components needed to support early development of the fertilized ovum

• Spermatogonia undergo mitotic and meiotic divisions after puberty.

• There is no recent discovery for spermatogonia producing cells.

• Continual process of spermatogenesis in males, who have potential to produce several million sperms in a single day

• Motile spermatozoa is unencumbered with unessential cytoplasm and orgenelles

Plasma concentration of gonadotropins and ovarian hormones

Luteinization depends on

1. Extrusion of Ovum

2. Luteinization inhibiting factor

Menstruation

• Decreased stimulation

• Vasospasm – PGF2α

• 40ml of blood and 35ml of serous fluid

• Fibrinolysin

• Leukorrhea during menstruation

Synthesis of steroid hormones

Thankyou