Tag: biology

The rhythmic reproductive cycle in the female primates is called as the menstrual cycle. The first menstruation begins at puberty and is called as menarche and is repeated at an average interval of about 28 / 29 days.

The reproductive cycle in the female primates is called menstrual cycle. The first menstruation begins at puberty and is called as menarche. In human females, menstruation is repeated at an interval of about 28/29 days, and the cycle of events starting from one menstruation till the next one is called as the menstrual cycle. In human beings, menstrual cycle ceases around 50 years of age; that is termed as menopause. 

The reproductive cycle in the female primates (e.g., monkeys, apes and human beings) is called as menstrual cycle. The first menstruation begins at puberty and is called as menarche. In human females, menstruation is repeated at an average interval of about 28/29 days, and the cycle of events starting from one menstruation till the next one is called as the menstrual cycle. One ovum is released (ovulation) during the middle of each menstrual cycle.

All the statements above are correct except the last one. Menstrual blood normally does not clots and flows through cervix and vagina along with inner lining of uterus. But it may clot also especially if there is blockage in cervix and free flow is obstructed. The menstrual blood contains not only blood but also tissue from the lining of the uterus. Clots are a natural way of controlling bleeding. Scientifically, it is a complicated and involved process that leads to fibrin being formed into a matrix. 
On the exposed parts of body like scraped knee, this mechanism leads to scab formation. But inside the uterus, the process results in a clot. Because blood in the uterus is mixed with many other cells and endometrial tissue, there is a difference between this clot and those seen on the skin. Whenever blood pools or is retained inside the uterus it is likely to clot. When menstrual blood and cells pass immediately outside the body, clots are less likely. As a general rule, the redder the blood is, the faster it has reached the outside. The blacker it is, the longer it took to exit the body. If the blood is accumulating faster than the body's ability to transfer it out of the uterus, clots are the result. Many women routinely have some clotting during menses. Factors that determine whether clots will occur include: the size of the uterus, the ability of the uterine myometrium (muscle) to contract, fibroids, adenomyosis, the diameter of the cervical canal through which the blood must flow, any obstruction to the outflow of menstrual products such as polyps, adhesions, etc.

Menopause is the cessation of the monthly cycle wherein ovaries do not respond to gonadotropic hormones produced by the anterior pituitary and do not secrete oestrogens and progesterone. It marks the end of a reproductive phase of the human female. Deposition of subcutaneous fat, the presence of pubic hair and development of mammary glands are secondary sexual characters in human females. The correct answer is A.

• Menstruation is a woman's monthly bleeding. It occurs so as to shed the lining of the uterus or womb. 
• In the menstrual cycle, the uterus gets prepared for implantation and the endometrium builds up. 
• After ovulation, if the egg released after fertilization, does not get implanted in the uterus, it leads to shedding off this endometrium and its lining and mucus and this is called menstruation. 

The level of progesterone hormone decreases after the regression of corpus luteum, causes the uterus to shed its lining and egg in a process termed as menstruation. 

• Menstruation is a woman's monthly bleeding. It occurs so as to shed the lining of the uterus or womb. In the menstrual cycle, the uterus gets prepared for implantation and the endometrium builds up.
•  After ovulation, if the released egg does not get implanted in the uterus, it leads to shedding off the endometrium and its lining and this is called menstruation and it generally lasts for 3-4 days.

• Menstruation is a woman's monthly bleeding. When the egg is released by the ovary, the body prepares for fertilization but building up the uterine layer and other hormonal changes. 
• However, if the egg is not fertilized, the body sheds this lining of the uterus and mucus and this is called menstrual blood and it passes from the uterus through the cervix and passes out the body through the vagina.

The mature egg is released from the ovary and pushed down the fallopian tube for it to fertilize. If no fertilization takes place, the egg degenerates and is shed from the body along with the uterine lining as well as the blood, which happens during the menstruation.
Thus, the correct answer is option B.