During reproduction,the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring.What are the process through which these events take place?

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1.Meiosis occurs during gametogenesis;it leads to reduction in  the number of chromosomes and haploid (n) gametes are formed.
2.During fertilisation,when two haploid gametes fuse,a diploid (2n) zygote is formed.

Why is the middle piece of human sperm considered as 'powerhouse of the sperm'?

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Middle piece contains numerous mito-chondria,which produce energy for the movement of sperm for the movement of sperm for fertilisation;so it is called the power house.

Somatic chromosome number is 40. What shall be the chromosome number in the cells of seminiferous tubules?

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40 chromosomes

Name the stages when oogenesis and spermatogenesis initiate in human female and male, respectively?

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Oogenesis starts during embryonic developmental stages of the female foetus while, spermatogenesis starts at puberty.

Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

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In this phase, progesterone stimulates the endometrial glands of the uterus to secrete a nutrient fluid for the foetus hence also the secretory phase.

During fertilization hundreds of sperms are in the vicinity of an egg cell; but only one sperm enters the ovum. How is this achieved.

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During fertilization when a sperm comes in contact with the egg it induces changes in zona pellucida of ovum and this blocks the entry of any other sperm. This ensures the entry of only one sperm.

The act of procreation in mammals and humans involve some basic steps. Mention them in a sequence?

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Insemination, fertilization, embryogenesis, implantation, development, parturition.

Testis / Ovary are called as primary reproductive organs while all the associated ducts and glands come under secondary organs. Give justification for it?

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Reproduction involves sex cells, so the organs that generate the sex cells are called as primary organs while all others will be called as secondary.

Testis like ovary develop within the pelvic cavity, but in the later part of the development testis descend out of the abdominal cavity . What could be the reason for it?

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Spermatogenesis – Required temperature is app.35⁰ C, which can be maintained if they descend out

The generating tissue must be accompanied by nursing tissue also. Elaborate this statement with respect to human testis?

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Testis – generating tissue- Generative layer of seminiferous tubule. Nursing tissue – Sertoli cells.

Penis consists of soft tissue and this condition is of no use for insemination. How is this problem overcome during the reproductive physiology?

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Penis –soft tissue has spongy, vascular tissue which gets filled with blood and thereby generates hydrostatic pressure for .erection

The spermatozoas need to be activated for bringing out the act of fertilization. What role does accessory sex glands play in this process?

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Accessory glands release fructose, ions, and activation principles.

Ovaries are made of soft tissue and are not fixed in any bony socket but are placed in abdominal cavity. So there is a possibility that they may get displaced. But this generally does not happen. How is this attained?

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Ovaries do not normally get displaced due to attached on the mesenteries within the abdominal cavity.

There is no direct connection between ovary and fallopian tube, so there is possibility that the ovum may be released within the abdominal cavity, but it does not happen. How does a fallopian tube prevent this situation?

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Fallopian funnel have fimbriated margins that develop a funneling effect to entrap the released ovum.

Spermatogenesis and spermatogenesis are two different processes but both are essential for male reproductive system. How do they differ from each other?

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Spermatogenesis is spermatogonia to spermatid, but spermeiogenesis is from spermatid to spermatozoa.

A sperm after being released in the vagina must reach the end of the fallopian tube to participate in the act of fertilization. What machinery comes into play for the said purpose?

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Sperm has to move so tail is required, mitochondria for energy generation, source of energy comes from the secretions.

Do LH and FSH have the same function in the male and female reproductive physiology? Justify your answer.

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LH in male stimulate Leidig cells to release androgens, but in females result in ovulation. FSH in males stimulates sertoli cells to release factors for spermeiogenesis but in females it stimulates a new follicle.

For completing the act of fertilization the sperm must fuse with the ovum, but the latter is surrounded by lot of extra follicular cells. How the sperm does manage to fuse with the ovum?

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Sperm acrosome release sperm lysins which digest the additional layers around the ovum.

The milk produced by the mother for the first few days is important for the baby not only energetically but also for some other reason. Elaborate on this statement?

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Colostrum is rich in defence molecules (antibodies) for the baby whose defenses are not mature enough to fight infections.

What is the name of network formed by the fusion of open ends of seminiferous tubules? Where does this network lead to?

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Rete testis. It leads to vas deference.