Human Reproduction

Which one of the following is the most likely root cause why menstruation is not taking place in regularly cycling human female?

1. Retention of well-developed corpus luteum
2. Maintenance of high concentration of sex hormones in the blood stream
3. Maintenance of the hypertrophical endometrial lining
4. Fertilisation of the ovum

A change in the amount of yolk and its distribution in the egg will affect:

1. Fertilisation
2. Pattern of cleavage
3. Formation of zygote
4. Number of blastomeres produced

In humans, at the end of the first meiotic division, the male germ cells differentiate into the:

1. secondary spermatocytes
2. spermatogonia
3. primary spermatocytes
4. spermatids

Which one of the following statements is incorrect about menstruation?

1. The beginning of the cycle of menstruation is called menarche
2. At menopause in the female, there is especially abrupt increase in gonadotropic hormones
3. The menstrual fluid can easily clot
4. During normal menstruation about 40 ml blood is lost

Which extraembryonic membrane in humans prevents desiccation of the embryo inside the uterus?

1. Yolk sac
2. Amnion
3. Chorion
4. Allantois

Which part of ovary in mammals acts as an endocrine gland after ovulation?

1. Stroma
2. Vitelline membrane
3. Germinal epithelium
4. Graafian follicle

Sertoli cells are regulated by the pituitary hormone known as-

1. LH
2. FSH
3. GH
4. Prolactin

Withdrawal of which of the following hormones is the immediate cause of menstruation?

1. Progesterone
2. FSH
3. FSH-RH
4. Estrogen

Grey crescent is the area -

1. Just opposite to the site of entry of sperm into ovum
2. At the point of entry of sperm into ovum
3. At the vegetal pole
4. At the animal pole

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

1. Corpus luteum will disintegrate
2. Estrogen secretion further decreases
3. Primary follicle starts developing
4. Progesterone secretion rapidly declines