NEET Biology Human Reproduction MCQs Set 10

Answer: (b) Penis

Explanation:
1. External genitalia of male is called penis, which is the passage for both urine and sperm

Answer: (d) spermiogenesis

Explanation:
1. The process of formation of spermatozoa from spermatids is called spermiogenesis.

Answer: (a) Outer layer of trophoblast

Explanation:
1. Chorionic villi is the modification of outer trophoblast layer of blastocyst, which get attached to the endometrium of uterus. This is called implantation

Answer: (d) Sertoli cell

Explanation:
1. Sertoli cells present in the mammalian testis, nourishes the sperms. That’s why Sertoli cells are also called nurse cells. These cells also produces the inhibin hormone which halts spermatogenesis

Answer: (d) Gastrula will be larger, while zygote and blastula will be of same size

Explanation:
1. Gastrula will be larger, while zygote and blastula will be of same size.

Answer: (a) Blastocyst

Explanation:
1. Blastocyst Formation At the next stage of development (morula), which produces an embryo with about 64 cells, a cavity is formed with in the cell mass. This cavity is called blastocyst cavity (blastocoel) and the embryo is termed as blastocyst.
2. Blastocyst composed of an outer envelops of cells the trophoblast or trophoectoderm and inner mass cell (embryoblast). The side of the blastocyst to which inner mass cell is attached is called embryonic pole (animal pole), while opposite side is the abembryonic pole

Answer: (d) Diaphragm

Explanation:
1. Condoms, cervical caps, diaphragms and intrauterine contraceptive devices (IUCDs) are all mechamical irth control devices.

Answer: (b) From animal pole in unfertilized egg

Explanation:
1. During fertilization, sperm enters from animal pole in unfertilized egg.

Answer: (b) Oxytocin

Explanation:
1. Doctors inject oxytocin hormone for the strong contraction of uterine wall.
2. Parturition
3. (i) The average duration of human pregnancy is about 9 months which is called the gestation period
4. (ii) The act of expelling the full term foetus from the mother’s uterus at the end of gestation period is called parturition
5. (iii) It is induced by a complex neuroendocrine mechanism
6. (iv) Parturition signals originates from the fully developed foetus and the palcenta, which induce mild uterine contractions called foetus ejection reflex
7. (v) This triggers the release of oxytocin from the maternal pituitary
8. (vi) Oxytocin induces stronger uterine muscle contractions
9. (vii) Relaxin increases the flexibility of the pubic symphysis and ligaments that helps to dilate the uterine cervix during labour pain
10. (viii) This leads to the expulsion of baby

Answer: (a) Gametes

Explanation:
1. Gametes. The major reproductive events in human beings are as follows
2. (i)Gametogenesis It is the formation of gametes. It includes spermatogenesis (formation of sperms) and oogenesis (formation of ova/eggs)
3. (ii)InseminationIt is the transfer of sperms by the male into the genital tract of the female
4. (iii)Fertilization Fusion of male and female gametes to form zygote is called fertilization
5. (iv)CleavageIt is rapid mitotic divisions of the zygote which convert the single celled zygote into a multicellular structure called blastocyst (blastula)
6. (v)ImplantationIt is the attachment of blastocyst to the uterine wall
7. (vi)PlacentationIt involves the formation of placenta which is the intimate connection between the foetus and uterine wall of the mother to exchange the materials
8. (vii)GastrulationIt is the process by which blastocyst is changed into gastrula with three primary germ layers
9. (viii)OrganogenesisIt is the formation of specific tissue, organs and organ systems from three primary germ layers
10. (ix)Parturition (child birth) it involves expelling of the baby from the mother’s womb (uterus)

Answer: (a) Cervical canal

Explanation:
1. The cervix is the part which joins the anterior wall of the vagina and opens into it. The cavity of the cervix is called cervix canal. The cervix communicates above with the body of the uterus by an aperture called internal os and with the vagina below by an opening the external os

Answer: (c) Semen

Explanation:
1. Seminal plasma is the combined secretion of three glands named (a) seminal vesicles (b) prostate gland (c) Cowper’s gland, together with sperm they collectively form semen

Answer: (a) Epimorphosis

Explanation:
1. Regeneration of tail in lizards is an example of epimorphosis. Epimorphosis takes place by the proliferation of the new tissue cell from the surface of wound.

Answer: (d) Retention of larval or embryonic trait in the adult body

Explanation:
1. Neoteny is the retention of larval or embryonic characters even after sexual maturity. It is shown by Axolotl larva or Ambystoma (tiger salamander) found in USA and Mexico.

Answer: (c) Graafian follicle

Explanation:
1. Corpus luteum (yellow body) is fromed from ruptured Graafian follicle.

Answer: (c) Statement I is false, but II is true

Explanation:
1. Statement I is false. Sperm live for some time in petridish but when they don’t get appropriate environment, they will die. At \(-196℃\) they can be stored for years. This is the temperature which is maintained at sperm bank
2. Statement II is true. Because sperm contain prostaglandins which causes uterine wall to contract

Answer: (c) Ovulation

Explanation:
1. Oral contraceptive is a preparation consisting of one or more synthetic female sex hormones taken by woman to prevent conception. Most oral contraceptives are combined pills consisting of an oestrogen, which blocks the normal process of ovulation and progesterone, which acts on the pituitary gland to block the normal control of menstrual cycle.

Answer: (a) Alecithal

Explanation:
1. The egg of human is almost free of yolk hence, called alecithal.

Answer: (a) I, III and IV only

Explanation:
1. Epidermis, including glands, hair, nails, etc is ectodermal in origin. Notochord and muscles are mesodermal in origin. Dermis of skin is also mesodermal. Enamel of teeth is ectodermal in origin.

Answer: (c) LH

Explanation:
1. In human female, the large plasma surge of luteinizing hormone (LH) causes induction of ovulation (release of ovum).

Answer: (b) Penis

Explanation:
1. The penis contains three cylindrical masses of erectile tissues – two dorsal corpora cavernosa (which run parallel on the dorsal part) and a central corpus spongiosum (which contain urethra).

Answer: (b) Spermatogonia - Spermatocyte-spermatid-sperm

Explanation:
1. In spermatogenesis, during growth phase some spermatogonia either due to growth or due to food storage become 2 or 3 times large of their original size and are known as primary spermatocytes, which undergo meiosis-I and as a result 2 haploid secondary spermatocytes are formed.
2. Futher, meiosis-II takes place that results in the foramtion of 4-spermatids. Then, these round, non-motile and haploid spermatids are transformed into thread-like motile, haploid (four) sperms.

Answer: (c) Mesoderm

Explanation:
1. All systems (except nervous system, gills and lungs), muscles, bone, heart, blood, kidney, reproductive system, coelom, lymph node, spleen, eustachian tube, adrenal cortex develop from mesoderm.

Answer: (a) Nurse cells

Explanation:
1. Sertoli’s cells are located in the seminiferous tubules, the structural and functional units of testes. These cells are also called nurse cells as these provide nourishment for differentiating spermatozoa (developing sperm).

Answer: (b) Secondary spermatocytes

Explanation:
1. During spermatogenesis, at the end of first meiotic division, the male germ cells differentiate into the secondary spermatocytes.