Sertoli cells are found in

Solution

Sertoli cells are found in the walls of seminiferous tubules of the testes. They anchor and provide nutrition to the developing germ cells especially the spermatids.

In vitro fertilisation is a technique that involves transfer of which one of the following into the fallopian tube?

Solution

In vitro fertilization is a process where fertilization of egg occurs outside the mother’s womb. This method is used as a major treatment for infertility. This method involves the removal of eggs from the female ovaries. This egg is then allowed to fertilize with sperm in a fluid medium in a test tube. The zygote is allowed to develop for a week. Either zygote or early embryo up to 8 blastomeres is then transferred into the fallopian tube to complete its further development. If the embryo is with more than 8 blastomeres, it is transferred into uterus for successful pregnancy. A baby conceived by fertilization that occurs outside mother body is called test-tube baby.

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

Solution

Fertilization of ovum is the most likely root cause why menstruation is not taking place in regularly cycling human female. In order for fertilization to occur, one of these sperm must attach itself to the ovum and penetrate its outer surface. The fertilized ovum will then continue travelling down the fallopian tube, taking several days until it reaches the uterus. When it arrives, it attaches itself to the lining of the uterus and continues to grow. If the ovum is not fertilized it will die and the progesterone and oestrogen hormone levels will drop. Without these hormones the prepared uterus lining breaks up and is released through the vagina. This is known as a ‘period’.

The correct sequence of spermatogenetic stages leading to the formation of sperms in a mature human testes is:

Solution

The formation of sperms in mature human testes completed in three important phases in gametogenesis-multiplication, growth and maturation phase. During these phases primarily germ cells change into spermatogonia then spermatocyte during growth phase which change into spermatoids and spermatids into sperms.

Seminal plasma in humans is rich in:

Solution

Human seminal plasma is a complex mixture of proteins,glycoproteins, peptides, glycopeptides, and prostaglandins secreted by organs of the male reproductive tract. The components of this fluid have been implicated in the suppression of immune response,agonistic effects on sperm-egg binding, and promotion of successful implantation of the human embryo. Seminal plasma in humans is rich in fructose and certain enzymes but poor in calcium.

Which one of the following is the correct matching of the events occurring during menstrual cycle?

Proliferative phase: Rapid regeneration of myometrium and maturation of Graafian follicle.
Development of corpus luteum :Secretory phase and increased secretion of progesterone.
Menstruation: Breakdown of myometrium and ovum not fertilised.
Ovulation: LH and FSH attain peak level and sharp fall in the secretion of progesterone.

Solution

The corpus luteum is essential for establishing and maintaining pregnancy in females. In the ovary, the corpus luteum secretes estrogens and progesterone, which are steroid hormones responsible for the thickening of the endometrium and its development and maintenance,respectively.

Which one of the following statements is incorrect about menstruation?

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

Solution

In human female, the periodic discharge of blood, mucus and cellular debris from uterine wall from non-pregnant women of sexual maturity is known as menstrual cycle. Few hours before the start of mensuration, the spiral arterioles constrict one by one resulting into the blanch mucosa. The mucosa shrinks and the death of the blood deprived tissues takes place.

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

Solution

In human, at the end of the first meiotic division, the male germ cells differentrate into the secondary spermatocytes.

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

Solution

The progesterone and estradiol continue the hypertrophy of endometrial lining in the uterus and fallopian tubes and maintain it throughout pregnancy. Progesterone is also necessary for the proper implantation of the foetus in the uterine wall. It stimulates the endometrial glands to secrete a nutrient fluid for the foetus, hence the term secetory phase. The progesterone inhibits the release of FSH so that it may not develop additional follicles and eggs.

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

Solution

Progesterone hormone which is secreted by the corpus luteum in the ovaries is responsible to stop ovulation(during pregnancy) and fixes the foetus to the uterine wall, facilitates placenta formation and controls the foetus development in uterus. If this hormone is withdrawn then fixation of foetus to uterine wall will not take place,formation of placenta will also not take place, ovulation starts from the ovaries and hence in human female menstruation starts.

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