Human Reproduction — Page 10 | NEET Biology

Q91

Which of these is not an important component of initiation of parturition in humans?

A Synthesis of prostaglandins

B Release of oxytocin

C Release of prolactin

D Increase in estrogen and progesterone ratio

Correct Answer

Option C

Solution

(c) Prolactin is for milk synthesis, not parturition initiation.

Q92

Hormones secreted by the placenta to maintain pregnancy are

A hCG, hPL, progestogens, prolactin

B hCG, hPL, estrogens, relaxin, oxytocin

C hCG, progestogens, estrogens, glucocorticoids

D hCG, hPL, progestogens, estrogens

Correct Answer

Option D

Solution

(d) Placenta secretes hCG, hPL, progestogens, and estrogens to maintain pregnancy.

Q93

Which of the following hormones is responsible for both the milk ejection reflex and the foetal ejection reflex?

A Relaxin

B Oestrogen

C Prolactin

D Oxytocin

Correct Answer

Option D

Solution

(d) Oxytocin causes uterine contractions (parturition) and milk ejection from mammary glands.

Q94

Freshly released human egg has

A one Y-chromosome

B one X-chromosome

C two X-chromosomes

D one X-chromosome and one Y-chromosome

Correct Answer

Option B

Solution

(b) Human females are XX; each egg carries 22 autosomes and one X chromosome.

Q95

Human eggs are

A Alecithal

B Microlecithal

C Mesolecithal

D Macrolecithal

Correct Answer

Option A

Solution

(a) Human eggs are alecithal — almost free of yolk, like most mammals.

Q96

In 28-day human ovarian cycle, ovulation occurs on

A Day 1

B Day 5

C Day 14

D Day 28

Correct Answer

Option C

Solution

(c) On day 14 a mature Graafian follicle ruptures and releases the ovum.

Q97

The growth of corpus luteum is initiated by

A Human chorionic gonadotropin

B Follicle stimulating hormone

C Luteinizing hormone

D Prolactin

Correct Answer

Option C

Solution

(c) LH causes ovulation and stimulates remaining follicular cells to develop into corpus luteum.

Q98

If mammalian ovum fails to get fertilized, which one of the following is unlikely?

A Corpus luteum will disintegrate

B Progesterone secretion rapidly declines

C Estrogen secretion further decreases

D Primary follicle starts developing

Correct Answer

Option C

Solution

(c) Estrogen does not decrease further; it maintains endometrium growth until corpus luteum degenerates.

Q99

In the human female, menstruation can be deferred by the administration of

A combination of FSH and LH

B combination of estrogen and progesterone

C FSH only

D LH only

Correct Answer

Option B

Solution

(b) Oral contraceptives (estrogen + progesterone) prevent FSH release and ovulation, deferring menstruation.

Q100

Which one of the following statements is incorrect about menstruation?

A During normal menstruation about 40 ml blood is lost

B The menstrual fluid can easily clot

C At menopause in the female, there is especially abrupt increase in gonadotropic hormones

D The beginning of the cycle of menstruation is called menarche

Correct Answer

Option B

Solution

(b) Menstrual fluid does not easily clot due to presence of fibrinolysin.