Multiple Choice Questions (MCQs): Human Reproduction - NEET MCQ

The glandular tissue of each breast is divided into 15-20 mammary lobes which contain cluster of alveoli. Cells of alveoli secretes milk.

Infundibulum and fimbriae are the parts of fallopian tube (oviduct) through which ovum released from ovary passes towards uterus. Fertilisation of ovum occurs in fallopian tube.

Mons pubis is the anterior most portion of the external genitalia of human females which is fatty area covered with the skin and pubic hair.

• Placenta connects the maternal system to the fetal system.
• It provides nutrients for the fetus.
• It also removes the excretory products that would be harmful to it.
• It also provides a gaseous exchange by providing oxygen and removing carbon dioxide.

The placenta also secretes estrogen, however, not oxytocin. Oxytocin is a hormone secreted by the posterior pituitary gland during parturition.

The middle layer of uterus is thick and muscular structure called myometrium that help in exhibiting strong contraction during delivery of the baby.

Development of fetus start from zygote divisions to form embryo. The embryo undergoes multiple divisions to form blastocysts that arrange into layers. The primary layers are ectoderm, mesoderm and endoderm.

• To use hormone as a detector for pregnancy, the hormone should be released only during pregnancy.
• Such hormones are hPL, hCG, and relaxin.
• Progesterone is not specific to pregnancy and hence cannot serve the purpose.

In female baby, oogenesis starts before the birth of baby after forming primary oocyte. Further development to ovum occurs after attaining puberty.

Each primary spermatocyte undergoes first meiotic division to produce 2 secondary spermatocytes, which further proceeds to second meiotic division to form 2 spermatids. So, each primary spermatocyte produces 4 sperms.

Seminiferous tubules contain Spermatogonia and Sertoli cells. Spermatogonium undergoes meiotic division to produce sperms and Sertoli cells provide nourishment to them.

FSH (follicle stimulating hormone) stimulates Sertoli cells to secrete spermatogenic substance. Sertoli cells function as nurse cells for differentiating spermatozoa.

Girls are born with 200-300 millions of primary oocytes but all of these oocytes do not get chance to mature and change into ovum because one ovary produce only one ovum each month in the middle of menstrual cycle. So, some 500 eggs are released by female during her reproductive life.

Testosterone hormone help in release of sperm from testis. This hormone is released by leydig cells present in between seminiferous tubules of testis.

Millions of sperms are released during insemination that reaches to ovum for fertilisation. Only one sperm enter the ovum by penetrating the zona pellucida layer of ovum using the enzyme present in its acrosome.

The stoppage of menstrual cycle in human female is called menopause. This indicates the end of reproductive phase of female at the age of about 50 years.

Menstrual cycles get stopped during pregnancy. Sometimes it becomes irregular due to stress and other hormonal activities of the body.

Menstrual cycle is divided into several phase starting from menses during which endometrium breaks and comes out through vagina for 4 to 5 days. Ovulatory phase occurs in the middle of menstrual cycle (14/15th day) during which egg is released.

After implantation of blastocysts, finger-like projections appear on the trophoblast called chronic villi which is surrounded by the uterine tissue and maternal blood.

The heart is formed first in foetus after one month of pregnancy. Limbs and digits after second months, limbs and external genital organs after three months and eye lids and hair after six months.

2. Scrotum helps in maintaining the low temperature of the testes necessary for spermatogenesis

Explanation:

• Spermatogenesis (the production of sperm) requires a temperature that is slightly lower than the normal body temperature. The scrotum, by keeping the testes outside the abdominal cavity, helps maintain this lower temperature necessary for optimal sperm production.

The other options are not accurate in this context:

1. The scrotum can contain lengthy ducts for the transfer of sperms: The scrotum does not primarily function to contain ducts; it houses the testes and helps regulate temperature.

2. Scrotum reduces the pressure around testes necessary for spermatogenesis: While the scrotum helps in temperature regulation, it does not specifically reduce pressure.

3. Scrotum can store huge amounts of sperms: The scrotum does not store sperm; rather, sperm is stored in the epididymis after production in the testes.