NEET Biology Human Reproduction MCQs Set 15

Answer: (a) Progesterone

Explanation:
1. Corpus luteum acts as a temporary endocrine gland, It secretes progesterone and relaxin. Progesterone is essential for promoting secretory changes in uterine endometrium (prepares uterus for implantation of fertilized ovum) and inhibits ovulation and menstrual cycle during pregnancy.)

Answer: (a) Ectoderm

Explanation:
1. Adrenal glands are paired structures located on the top of the kidneys. Each adrenal gland has two parts external adrenal cortex and internal adrenal medulla. The adrenal cortex is derived from themesoderm of the embryo. The adrenal medulla develops from the neuroectoderm of the embryo.

Answer: (c) I

Explanation:
1. Sperm entry stimulates the secondary oocyte to complete the suspended second meiotic division. This produces a haploid mature ovum and a second polar body. The head of the sperm which contains the nucleus separates from the middle piece and tail and becomes male pronucleus. The second polar body and the sperm tail degenerates. The nucleus of the ovum is now called female pronucleus. The male and female pronucleus move towards each other. Their nuclear membrane disintegrates; mixing up of the chromosome of a sperm and an ovum is called karyogamy or amphimixis. The fertilized ovum (egg) is now called zygote

Answer: (b) Ovary

Explanation:
1. Relaxin is secreted by ovary. Relaxin increases the flexibility of the pubic symphysis and ligaments of the sacroiliac and sacrococcygeal joints that helps to dilate the uterine cervix during labour pain

Answer: (c) Capacitation

Explanation:
1. Maturation of sperm before penetration of egg is called capacitation.

Answer: (a) Prophase-I

Explanation:
1. Oogenesis starts in the foetal stage. Till the time of birth they remains in prophase-I. The oogenesis resumes at the time of puberty by \(\mathrm{GnRH}\) produced by hypothalamus

Answer: (c) Chick

Explanation:
1. In birds and other polylecithal egg containing animals, cleavage (division) are restricted to a small part of cytoplasm and nucleus in animal pole of egg. Such type of cleavage is termed as ‘meroblastic cleavage’.

Answer: (a) Fertilization of the ovum

Explanation:
1. If fertilization occurs and foetus is implanted in the endometrium, the trophoblast cells of the developing placenta secrete a hormone human Chorionic Gonadotrophic (hCG).This hormone, like LH, maintains the corpus luteum and the secretion of progesterone and estradiol by it. These two hormones check the breakdown of the endometrium of the uterus. The absence of menstrual bleeding is the earliest sign of pregnancy.

Answer: (c) 3rd month

Explanation:
1. 3rd month.
2. Summary of important development changes in the human embryo

Answer: (a) Corpus luteum

Explanation:
1. After releasing ovum the structure left is called corpus luteum. It secretes progesterone, which maintains the pregnancy

Answer: (a) B and C

Explanation:
1. B to C represents primary and tertiary follicles respectively.
2. Ovary is internally differentiated into four parts, i.e., outer germinal epithelium of cubical cells, a delicate sheath of connective tissue or tunica albuginea, a cortex of dense connective tissue with reticular fibres, spindle-shaped cells, ovarian follicles and a few blood vessels while the central part of medulla is made of less dense connective tissue with elastic fibres, smooth muscles, a number of blood vessels and a few nerves.
3. Maturation of secondary oocyte is completed in mother’s oviduct after the sperm entry into it for fertilization. \(2°\) oocyte stops advancing further after the completion of metaphase-II. Sperm entry restart the cell cycle by breaking down MPF (Maturation Promoting Factor) and truning on APF (Anaphase Promoting Factor)

Answer: (c) Both (a) and (b)

Explanation:
1. Ejaculatory DuctsThe ejaculatory ducts are the two short tubes each formed by the union of ducts from seminal vesicle and vas deferens. They pass through the prostate gland and join the prostatic part of the urethra. The ejaculatory ducts are composed of the fibrous, muscular and columnar epithelial tissue. Ejaculatory ducts carry sperms and secretion of seminal vesicles

Answer: (c) Uterus

Explanation:
1. The wall of uterus is composed of three layers of tissues-the perimetrium (outer covering), the myometrium (middle layer of smooth muscle fibre) and endometrium (the mucus membrane lining).

Answer: (c) 22 months

Explanation:
1. Gestation includes, fertilization, implantation and developmenty. It lasts from conception to hatching or birth.
2. Gestation period in rabbit – 28 to 30 days
3. In man - 280 days
4. In rat (minimum) - 15 days
5. In elephant (maximum) - 22 months

Answer: (b) Germ cell

Explanation:
1. Germ cell is immortal.

Answer: (c) FSH, LH, Oestrogen

Explanation:
1. Follicle Stimulating Hormone (FSH), Luteinzing Hormone (LH) and oestrogen, all play an important role in controlling the menstrual cycle in human females.

Answer: (b) Seminiferous tubule

Explanation:
1. Leydig’s cells or interstitial cells lie between the seminiferous tubules and secrete the male hormone, testosterone that controls spermatogenesis.

Answer: (b) Colostrum have antibody

Explanation:
1. Colostrum have antibody-A which work against the pathogenicity in newborn. So, it is recommended by doctors to feed new born from breast milk as for as possible

Answer: (a) Menstrual cycle

Explanation:
1. Menstrual Cycle
2. (i) The rhythmic series of changes that occurs in the reproductive organs of female primates (monkeys, apes and human beings) is called menstrual cycle.
3. (ii) It is repeated at an average interval of about 28/29 days.
4. The first appearance of menstruation at puberty is called menarche

Answer: (b) Hyaluronidase

Explanation:
1. The acrosome of sperm contains large quantities of proteolytic enzymes, particularly hyaluronidase, which digests the hyaluronic acid, a constituent of the extracellular matrix. It allows the sperm to digest a path through the zona pellucida to the oocyte.

Answer: (b) Mitosis of zygote into blastomeres

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

Answer: (c) Blastocyst – Uterine wall

Explanation:
1. Implantation is the attachment of the blastocyst to the uterine wall. It access after the seven days of fertilisation

Answer: (a) Ectoderm

Explanation:
1. Ectoderm.
2. Fate of three germ layers
3. Mesoderm Dermis of skin, circulatory system, muscles, bones (except facial)
4. Endoderm Lining of \(\mathrm{Gl}\) tract, lining of lungs, kidney ducts and bladder, thymus, thyroid tonsils
5. Ectoderm Epidermis of skin, tooth enamel, lens and cornea of the eye outer ear Brain and spinal cord, facial bones skeletal muscles in the head
6. All bones are derived from the mesoderm but only facial bones which are derived from the ectoderm

Answer: (a) Transfer of zygote into the fallopian tube

Explanation:
1. GIFT(Gamete Intra Fallopian Transfer) is the transfer of an ovum collected from a donor into the fallopian tube of another female who can not produce one but can provide suitable environment for fertilization and further development. In the same way ZIFT is used for zygote.

Answer: (a) Penis

Explanation:
1. Labium majora are two large thick folds of skin, which form the boundary of vulva. The labia majora are considered homologous to the scrotum of the male.