Human Reproductive System: Menstrual Cycle, Fertilisation, Implantation & Placenta: 17 MCQs with answers

Menarche

Menarche is the beginning of menstruation at puberty, around age 13. Menopause is its cessation.

The first day of menstrual flow

The period is counted from the day of the onset of menstrual flow to the next onset after 28 days.

Luteinizing hormone

The pituitary releases an LH surge that ruptures the mature Graafian follicle, releasing the egg.

Fallopian tube

The site of fertilisation is the oviduct or fallopian tube, not the uterus.

True

Ovulation occurs on the 13th or 14th day of the menstrual cycle when the mature Graafian follicle ruptures under the influence of **LH**.

Menstruation is also absent before puberty and after menopause

Menstruation is absent before puberty, during pregnancy, and after menopause, so a missed period is not proof of pregnancy alone.

Thickens and rebuilds the uterine wall

Estrogen secreted by the growing follicle reactivates and thickens the uterine wall.

Progesterone falls and the endometrium is shed

Without fertilisation, the corpus luteum degenerates, progesterone drops, and the endometrium is shed as menstruation.

Lysosomal enzymes from the acrosome

The acrosome releases lysosomal enzymes that digest the egg's limiting membranes, clearing a path for the sperm.

Amphimixis

Amphimixis is the fusion of the haploid pronuclei, restoring the diploid number of chromosomes in the zygote.

The zygote's reserve food lasts only about 7 days

The zygote's reserve food is sufficient for only about 7 days, so implantation is needed for nourishment and oxygen from the mother.

They never mix; a membrane separates them

A membrane always separates foetal and maternal blood, and exchange of materials occurs by diffusion.

The Graafian follicle is rupturing and releasing the egg

Ovulation occurs on day 13 or 14 when the mature Graafian follicle ruptures under the influence of LH.

Both A and R are true, and R correctly explains A

The placenta produces progesterone and estrogen, which is exactly why it functions as an endocrine organ.

Zygote → morula → blastocyst → implantation

The zygote divides to form the morula, which becomes the blastocyst, which then implants in the uterine wall.

Ovulation will not occur

The LH surge ruptures the Graafian follicle and releases the egg; blocking it prevents ovulation.

Estrogen → LH Surge → Ovulation → Corpus Luteum → Progesterone → Implantation

The correct sequence is: after the peak in estrogen, the LH surge triggers ovulation, which is followed by the formation of the corpus luteum that secretes progesterone. Progesterone is essential for preparing the uterine lining for implantation.