Biology · Human Reproduction · NEET
The menstrual cycle is found in primates only. This means humans, apes and monkeys. Other mammals do not have a menstrual cycle. They have an oestrus cycle instead. So the menstrual cycle is a special primate feature. NEET asks this directly, so remember: menstrual = primates.
No. Humans do NOT have an oestrus cycle. Humans are primates, so humans have a menstrual cycle. The oestrus cycle is only in non-primate mammals like cows, sheep, rats, deer, dogs and tigers. This is a common trap in NEET, so do not mix them up.
The main difference is the group of animals. Menstrual cycle is in primates (humans, apes, monkeys). Oestrus cycle is in non-primate mammals (cows, sheep, rats, dogs, tigers). Another difference: in the menstrual cycle the built-up uterus lining (endometrium) breaks down and comes out as bleeding if there is no pregnancy. In the oestrus cycle there is no such bleeding; the lining is reabsorbed.
NCERT lists these non-primate mammals as examples of the oestrus cycle: cows, sheep, rats, deer, dogs and tigers. These are exactly the examples NEET can ask, so learn this short list by heart. All of them are non-primates.
In primates, if the released ovum is not fertilised, the thick uterus lining (endometrium) breaks down and flows out as menstruation. In non-primate mammals, the lining is not shed as bleeding; the body reabsorbs it. For NEET, you mainly need the fact that only primates show menstruation, not the deep reason.
No, they are not the same. Menstruation is only ONE phase — the bleeding when the endometrium breaks down. The menstrual cycle is the whole repeating series of events (about 28/29 days) that includes menstruation, the follicular phase, ovulation and the luteal phase. So menstruation is a part inside the menstrual cycle.
Which of the following statements are correct regarding female reproductive cycle? A. In non-primate mammals cyclical changes during reproduction are called oestrus cycle. B. First menstrual cycle begins at puberty and is called menopause. C. Lack of menstruation may be indicative of pregnancy. D. Cyclic menstruation extends between menarche and menopause.
Match Column I with Column II: Column I: a. Proliferative Phase b. Secretory Phase c. Menstruation Column II: i. Breakdown of endometrial lining ii. Follicular Phase iii. Luteal Phase
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Only primates — humans, apes and monkeys. All other mammals have the oestrus cycle.
Cow, dog and tiger are three NCERT examples. Others are sheep, rat and deer. All are non-primate mammals.
No. There is no menstrual bleeding in the oestrus cycle. Menstrual bleeding (endometrium breakdown) happens only in the menstrual cycle of primates.
Both are controlled by ovarian and pituitary hormones such as FSH, LH, oestrogen and progesterone. The hormone control is similar; the visible difference is the shedding of the endometrium in primates.
About 28 to 29 days, as stated in NCERT. It repeats between menarche and menopause.
