Question

Draw a neat and well labeled diagram of T.S of ovary and describe the menstrual cycle in human females.

Answer 1

Hint: The ovary is a primary organ found in the female reproductive system that gives out or produces an ovum.
When released it travels down to the fallopian tube into the uterus, where it may get fertilized by a sperm.
Ovary is mainly present on each side of the body.

Complete answer:
Ovaries are the primary female sex organs that produce the female gamete known as ovum or egg and several steroid hormones.
There are two ovaries present on each side of the lower abdomen.
Each ovary is covered by a thin layer of epithelium which includes the ovarian stroma.
The stroma is divided into two zones:
1. A peripheral cortex
2. An inner medulla
Female accessory duct consists of fallopian tubes, uterus, vagina.
Menstrual cycle: The reproductive cycle in the female primates is known as menstrual cycle.
In human females, menstruation is repeated at an average interval of about 28/29 days.
Menarche: It is the starting of the menstrual cycle.
Menopause: It is the ceases of the menstrual cycle usually occurs at the age of 50 years.

Various events during a menstrual cycle are:
(i) Menstrual phase: It expands from 1st to 4th day of the cycle.
It usually occurs in the absence of fertilization.
During this phase bleeding occurs as the endometrium of the uterus is descended.
 After the 4th day, once again the FSH secretion is resumed and the new follicle starts developing.
(ii) Follicular phase: In this phase, the uterus enters in a proliferative phase.
This phase occurs from 5th to 13th day of the cycle.
During this phase a new primordial follicle in the ovary develops due to the action of FSH.
It changes into graafian follicle and as a result production of estrogen starts.
Also the uterus undergoes proliferation.
 (iii) Ovulatory phase: During this phase, the process of ovulation starts.
It occurs on the 14th day.
Mature, graafian follicle ruptures and bursts out to release the ovum.
This ovum along with the follicular fluid is picked up by the fimbriae of the infundibulum which is a part of the fallopian tube.
Due to the absence of any sperm, ovum will not get fertilized and degenerates.
(iv) Luteal phase: It takes place between 15th to 28th days of the cycle.
Ovarian changes : In the ovary, corpus luteum is formed from empty graafian follicle.
Progesterone is secreted here
If ovum is not fertilized, corpus luteum degenerates.
Uterine changes: Under the impact of progesterone, there is an increase in the thickness of endometrium lining.
Progesterone is responsible for the maintenance of pregnancy.
But when the progesterone source is cut off, endometrium scraps off and thus leads to menstruation.

Note: Sexually transmitted disease: They are the diseases which are transmitted through sexual contact with the infected individual.
For example: Gonorrhea, Syphilis, Hepatitis B, Genital herpes, AIDS etc.
Infertility: It means not able to conceive even after the two years of marriage without use of any contraceptive devices.