Which one of the following is the most likely reason of not occurring regular menstruation cycle in females?
Fertilisation of the ovum
maintenance of the hypertrophical endometrial lining
Maintenance of high concentration of sex hormones in the blood stream
Maintenance of high concentration of sex hormones in the blood stream
A.
Fertilisation of the ovum
If fertilisation occurs and the foetus is implanted in the endometrium the trophoblast cells of the developing placenta secrete a hormone human chorionic Gonadotrophic (hCG). This hormone-like LH maintains the corpus luteum and the secretion of progesterone and estradiol by it. These two hormones check the breakdown of the endometrium of the uterus. The absence of menstrual bleeding is the earilest sign of pregnancy.
The correct sequence of spermatogenetic stages leading to the formation of sperms in mature human testis is
spermatocyte-spermatoogonia-spermatid-sperms
spermatogonia-spermatocyte-spermatid
spermatid-spermatocyte-spermatogonia-sperms,
spermatid-spermatocyte-spermatogonia-sperms,
Which one of the following correctly describes the location of some body parts in the earthworm Pheretima?
Two pairs of accessory glands in 16-18 segments
Four pairs of spermathecae in 4-7 segments
One pair of ovaries attached at intersegmental septum of 14th and 15th segments
One pair of ovaries attached at intersegmental septum of 14th and 15th segments
In humans, at the end of the first meiotic division, the male germ cells differentiate into the
Primary spermatocytes
Secondary spermatocytes
spermatids
spermatids
Seminal plasma in human is rich in
fructose, calcium and certain enzymes
fructose and calcium but has no enzymes
glucose and certain enzymes but has no calcium
glucose and certain enzymes but has no calcium
In the human female, menstruation can be deferred by the administration of
LH only
Combination of FSH and LH
Combination of estrogen and progesterone
Combination of estrogen and progesterone
Which part of ovary in mammals acts as an endocrine gland after ovulation?
Graaffian follicle
Stroma
Germinal epithelium
Germinal epithelium
In human adult females, oxytocin
is secreted by the anterior pituitary
stimulates the growth of mammary glands
stimulates pituitary to secrete vasopressin
stimulates pituitary to secrete vasopressin
Which extraembryonic membrane in humans prevents desiccation of the embryo inside the uterus?
Chorion
Allantois
Yolk sac
Yolk sac
Which one of the following pairs of organs includes only the endocrine glands?
Parathyroid and adrenal
Pancreas and parathyroid
Thymus and testes
Thymus and testes
