. Luteal or secretory phase During luteal phase, the remaining part of the Graafian follicle is transformed into a transitory endocrine gland called corpus luteum. The corpus luteum secretes large amount of progesterone which is essential for the maintenance of the endometrium. If Fertilization takes place, it paves way for XII Std Biology-Zoology Chapter- XII Std Biology-Zoology Chapter- Human Reproduction Days (b) Events in the ovary (c) Ovarian hormones (c) Events in the endometrium of the uterus Highly proliferated and vascularized endometrium Thickness of the endometrium Bleeding and sloughing (menstruation) Several follicles start developing Single mature follicle Ovulation Corpus luteum Corpus albicans Lutenizing hormone(LH) th day LH Surge triggers ovulation Follicle stimulating hormone(FSH) Luteal phase Follicular phase Oestrogen Several follicles start developing Progesterone (a) FSH and LH secreted by the anterior pituitary Menstrual phase Follicular phase Luteal phase Fig.
. Different phases of the menstrual cycle POLY CYSTIC OVARY SYNDROME (PCOS) PCOS is a complex endocrine system disorder that affects women in their reproductive years. Polycystic means ‘many cysts’. It refers to many partially formed follicles on the ovaries, which contain an egg each.
But they do not grow to maturity or produce eggs that can be fertilized. Women with PCOS may experience irregular menstrual cycles, increased androgen levels, excessive facial or body hair growth ( hirsutism ), acne, obesity, reduced fertility and increased risk of diabetes. Treatment for PCOS includes a healthy lifestyle, weight loss and targeted hormone therapy. the implantation of the fertilized ovum.
The uterine wall secretes nutritious fluid in the uterus for the foetus. So, this phase is also called as secretory phase. During pregnancy all events of menstrual cycle stop and there is no menstruation. In the absence of Fertilization, the corpus luteum degenerates completely and leaves a scar tissue called corpus albicans .
It also initiates the disintegration of the endometrium leading to menstruation, marking the next cycle. XII Std Biology-Zoology Chapter- XII Std Biology-Zoology Chapter-