Which one of the following statements is false in respect of viability of mammalian sperm ?

Sperm is viable for only up to 24 hours.
Survival of sperm depends on the pH of the medium and is more active in alkaline medium.
Viability of sperm is determined by its motility.
Sperms must be concentrated in a thick suspension.

About which day in a normal human menstrual cycle does rapid secretion of LH (Popularly called LH-surge) normally occurs?

14^thday
20^thday
5^thday
11^thday

Solution

At 14^th day of normal human menstrual cycle rapid secretion of LH normally occurs.

The figure given below depicts a diagrammatic sectional view of the female reproductive system of humans. Which one set of three parts out of I-VI have been correctly identified ?

(II) Endometrium (III) Infundibulum, (IV) Fimbriae
(III) Infundibulum, (IV) Fimbriae, (V) Cervix
(IV) Oviducal funnel, (V) Uterus, (VI) Cervix
(I) Perimetrium, (II) Myometrium, (III) Fallopian tube

Solution

In the given figure

III - marked portion is Infundibulum

IV - marked portion is Fimbriae

V - marked portion is Cervix

The testes in humans are situated outside the abdominal cavity insides pouch called scrotum. The purpose served is for:

maintaining the scrotal temperature lower than the internal body temperature
escaping any possible compression by the visceral organs
providing more space for the growth of epididymis
providing a secondary sexual feature for exhibiting the male sex

Solution

The testes are present in the scrotum which maintains the scrotal temperature below 2°C of the internal body temperature.

The part of fallopian tube closest to the ovary is:

isthmus
infundibulum
cervix
ampulla

Solution

The part of fallopian tube closest to the ovary is infundibulum. Infundibulum possess finger-like projections called fimbriae that help in collection of ovum after ovulation. It leads to wider part of oviduct called ampulla. The last part of oviduct is isthmus that has an arrow lumen and joins the uterus.

Which one of the following statements about human sperm is correct?

Acrosome has a conical pointed structure used for piercing and penetrating the egg, resulting in fertilisation
The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilisation
Acrosome serves as a sensory structure leading the sperm towards the ovum
Acrosome serves no particular function

Solution

Acrosome is a small pointed structure at the tip of nucleus. It breaks down just before fertilization, releasing hydrolytic enzymes that assist penetration between follicle cells that surrounds the ovum, thus facilitating fertilization.

The second maturation division of the mammalian ovum occurs

shortly after ovulation before the ovum makes entry into the fallopian tube
until after the ovum has been penetrated by a sperm
until the nucleus of the sperm has fused with that of the ovum
in the graafian follicle following the first maturation division

Solution

In Oogenesis, the second maturation division occurs until after the ovum has been penetrated by a sperm. Oogenesis involves the formation of haploid female gametes, ova, from this diploid egg mother cells, oogonia of ovary of female organism.

The signals for parturition originate from:

placenta only
placenta as well as fully developed foetus
oxytocin released from maternal pituitary
fully developed foetus only

Solution

Parturition is the process of delivery of the foetus. The signals for parturition originate from the fully developed foetus and placenta that induce uterine contraction called foetal ejection reflex. This triggers the release of oxytocin hormone from pituitary. This in turn leads to expulsion of the baby out of uterus.

Seminal plasma in human males is rich in :

fructose and calcium
glucose and calcium
DNA and testosterone
ribose and potassium

Solution

Seminal plasma in human males are rich in fructose,calcium and certain enzymes. They provide a medium for transport of sperms, nourishes and activates sperms.

Vasa efferentia are the ductules leading from

testicular lobules to rete testis
rete testis to vas deferens
vas deferens to epididymis
epididymis to urethra

Solution

Vasa efferentia are ductules leading from rete testis to vas deferens. The rete testis is ananastomosing network of tubules located in the hilum of the testicles that carries sperm from the seminiferous tubules to the vasa efferentia.

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