Human Reproduction MCQs for NEET — Zoology Questions with Answers

The text states: 'Placenta also acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogens, progestogens, etc. In the later phase of pregnancy, a hormone called relaxin is also secreted by the ovary.' It specifically mentions relaxin from the ovary, not the placenta.

The NCERT text states, 'hCG, hPL and relaxin are produced in women only during pregnancy.' It also mentions that 'estrogens, progestogens, cortisol, prolactin, thyroxine, etc., are increased several-folds in the maternal blood' during pregnancy, implying progestogens are present even when not pregnant, albeit at lower levels.

According to the NCERT text, 'In human beings, after one month of pregnancy, the embryo’s heart is formed. The first sign of growing foetus may be noticed by listening to the heart sound carefully through the stethoscope.'

The NCERT states, 'After implantation, finger-like projections appear on the trophoblast called chorionic villi which are surrounded by the uterine tissue and maternal blood.'

The NCERT text specifies, 'The placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and from the embryo.' This implies both supply of nutrients/oxygen and removal of waste.

The NCERT states that the placenta 'facilitate the supply of oxygen and nutrients to the embryo and also removal of carbon dioxide and excretory/waste materials'. It also 'acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogens, progestogens, etc.'. Oxytocin release is triggered by the foetal ejection reflex and comes from the maternal pituitary, not the placenta.

The NCERT text says, 'The signals for parturition originate from the fully developed foetus and the placenta which induce mild uterine contractions called foetal ejection reflex. This triggers release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscles and causes stronger uterine contractions.'

The NCERT states, 'By the end of about 24 weeks (end of second trimester), the body is covered with fine hair, eye-lids separate, and eyelashes are formed.' Other options correspond to different stages.

The NCERT states, 'As a result, the blastocyst becomes embedded in the endometrium of the uterus (Figure 2.11 step H). This is called implantation and it leads to pregnancy.'

The NCERT states, 'The morula continues to divide and transforms into blastocyst...'