NEET Biology Human Reproduction MCQs Set 18

Answer: (a) Testis does not descend into scrotal sac

Explanation:
1. The male humans, if testes fail to descend into the scrotal sac, it is called cryptorchidism.

Answer: (a) Manchette

Explanation:
1. In the middle piece of sperm, cytoplasm is found in the form of a thin sheet calledManchette.

Answer: (a) A-follicle, B-corona radiata, C-zona pellucida

Explanation:
1. A-Follicle, B-Corona radiata, C-Zona pellucida

Answer: (a) Cowper’s gland

Explanation:
1. Cowper’s gland
2. Greater vestibular glands (Bartholin’s gland) are packed glands situated on each side of vaginal orifice. These glands are homologous to male bulbourethral (Cowper’s) gland and secretes viscus fluid that supplements the lubrication during sexual intercourse.
3. The lesser vestibular glands (paraurethral glands or glands of Skene) are numerous minute glands that are present on either side of the urethral orifice (opening). These glands are homologous to the male prostate glands and secrete mucus

Answer: (d) Scrotum

Explanation:
1. Scrotum is homologous to labia majora in females. It is pouch of deeply pigmented skin divided into two separate sacs. Each sac contains one testis

Answer: (b) Vas deferens

Explanation:
1. Vas deferens is large duct that arises from cauda epididymis and reach up to seminal vesicles.

Answer: (b) Drawing food for the developing cell

Explanation:
1. In mammalian embryo, trophoectoderm draws food for the developing cell.

Answer: (d) During prenatal development

Explanation:
1. Oogenesis or primordial follicles starts their development at the foetal stage but after birth this development stops and again resumes at the puberty stage

Answer: (b) Oestrogen secretion further decreases

Explanation:
1. If mammalian ovum fails to get fertilized, the oestrogen secretion does not decrease further.

Answer: (b) Be sterile

Explanation:
1. Secondary sexual characters and functioning of testicular interstitial cells depends upon the LH but spermatogenesis depends upon FSH

Answer: (c) Blastocoel

Explanation:
1. Pseudocoelom is a persisted blastocoel. It lacks definite mesoderm lining.

Answer: (b) Either zygote or early embryo upto 8 celled stage

Explanation:
1. In in vitro fertilization, the zygote or early embryos upto 8 blastomeres are transferred into the fallopian tube. If the embryo is more then 8 blastomeres then it is transferred into uterus called as IUD.

Answer: (d) On either sides of vagina in human

Explanation:
1. Greater vestibular glands (Bartholin’s gland) are packed glands situated on each side of vaginal orifice. These glands are homologous to male bulbourethral (Cowper’s) gland and secretes viscus fluid that supplements the lubrication during sexual intercourse.
2. The lesser vestibular glands (paraurethral glands or glands of Skene) are numerous minute glands that are present on either side of the urethral orifice (opening). These glands are homologous to the male prostate glands and secrete mucus

Answer: (b) Size and volume

Explanation:
1. Undifferentiated primordial germ cells undergo mitotic division to produce spermatogonia. Each spermatogonium grows to a large primary spermatocyte by obtaining nutrients from the nursing cells. The DNA content remains same (2\(n\)) in both spermatogonia and primary spermatocyte.

Answer: (c) Proliferative phase

Explanation:
1. Follicular phase is also called the proliferative phase.
2. Generally, menstrual cycle have four phases
3. (i) Menstrual phase (a) The soft tissue of endometrial lining of the uterus disintegrates causing bleeding.
4. (b) The unfertilized egg and soft tissue are discharged.
5. (c) It lasts 3-5 days.
6. (ii) Follicular Phase/Proliferative Phase (a) The primary follicles in the ovary grow and become a fully mature Graafian follicle.
7. (b) The endometrium of the uterus is regenerated due to the secretion of LH and FSH from anterior pituitary and ovarian hormone, estrogen.
8. (c) It least for about 10-14 days.
9. (iii) Ovulatory Phase (a) Rapid secretion of LH (LH surge) induces rupture of Graafian follicle, thereby leading to ovulation (release of ovum).
10. (b) It lasts for only about 48 hr.
11. (iv) Luteal Phase/Secretor Phase (a) In this phase the ruptured follicle changes into corpus luteum in the ovary and it begins to secrete the hormone progesterone.
12. (b) The endometrium thickens further and their glands secrete a fluid into the uterus.
13. c) If ovum is not fertilized, the corpus luteum undergoes degeneration and this causes disintegration of the endometrium leading to menstruation

Answer: (b) 300 million

Explanation:
1. Ejaculation or seminal emission is the foreceful expulsion of semen during sexual intercourse. At an average ejaculation, 3mL of semen contain about 300 million spermatozoa.

Answer: (b) FSH

Explanation:
1. FSH (follicle Stimulating Hormone) is secreted from the anterior lobe of pituitary. It stimulates growth of ovarian follicles and secretion of oestrogen in female and spermatogenesis in male.

Answer: (b) Fallopian tube

Explanation:
1. Fallopian tube or oviduct is the site of fertilization in mammals. The embryo develops upto blastocyst stage in fallopian tube.

Answer: (a) A-Allantois; B-blood vessel

Explanation:
1. Extraembryonic or Foetal Membranes
2. The growing embryo/foetus develops four membranes called the extraembryoic or foetal membranes. These include chorion, aminion, allantois and yolk sac
3. (i) Chorion It is made up of trophoblast outside and somatopleuric extraembryonic mesoderm inside. It completely surrounds the embryo and protects it. It also takes part in the formation of placenta
4. (ii) Amnion It is composed of trophoblast inside and somatopleuric extraembryonic mesoderm outside. The space between the embryo and the amnion is called the amniotic cavity, which is filled with a clear, watery fluid secreted by both the embryo and the membrane. The amniotic fluid prevents dessication of the embryo and acts as a protective cushion that absorbs shocks
5. (iii) Allantois The allantois is composed of endoderm inside and splanchnopleuric extraembryoic mesoderm outside. It is a sac like structure, which arises from the gut of the embryo near the yolk sac. In human the allantois is small and non-functional except for furnishing blood vessels to the placenta
6. (iv) Yolk Sac The primary yolk sac consists of endoderm inside and splanchnopleuric extraembryoic mesoderm outside. The yolk sac is non-functional in human beings except that it functions as the site of early blood cell formation

Answer: (c) Lack of progesterone

Explanation:
1. Due to lack of progesterone, uterine endmetrium, epithelial glands and connective tissue are broken in menstrual cycle.

Answer: (d) Maintaining the scrotal temperature lower than the internal body temperature

Explanation:
1. The testes in humans are situated outside the abdominal cavity in scrotal sacs. This is because the temperature of scrotal sac is \(25℃\) lesss than internal body temperature.

Answer: (a) Formation of sperms from small clumps of cells

Explanation:
1. Epimorphosis is a process that replaces a lost organ of the body by proliferating new cells from the surface of the wound or injured part, e.g., regeneration of tail in lizard, replacement of arm in starfish and limb in salamander.

Answer: (c) The weight of the child

Explanation:
1. Whether a child died after normal birth or died before birth can be confirmed by measuring the weight of the child.

Answer: (a) Changing of spermatid to spermatozoa

Explanation:
1. The transformation of spermatids into spermatozoa is called spermiogenesis or spermateliosis. The spermatids are later on known as sperms. After spermiogenesis head becomes embedded in the Sertoli cells and are finally released from the seminiferous tubules by process called spermiation

Answer: (c) Produce spermatozoa

Explanation:
1. The main function of seminiferous tubules is to produce spermatozoa. Inflammation of seminiferous tubules could interfere with the ability to produce spermatozoa