Human Reproduction MCQ Quiz in मल्याळम - Objective Question with Answer for Human Reproduction - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Prostate

Concept:

• The male reproductive system in humans consists of several organs, some of which are paired and some that are singular.
• The primary reproductive organs are the testes, which are paired. Other structures include the vas deferens, seminal vesicles, prostate gland, bulbourethral glands, and the penis.
• Among these, the prostate gland is a singular organ, unlike the paired organs such as the seminal vesicles, bulbourethral glands, and epididymis.

Explanation:

• Seminal Vesicle: These are a pair of glands that secrete fluid that partly composes the semen. They are located behind the bladder and are paired organs.
• Prostate: The prostate gland is a singular gland that surrounds the urethra just below the bladder. It secretes a fluid that nourishes and protects sperm. During ejaculation, this fluid is expelled with sperm as semen.
• Bulbourethral Gland: Also known as Cowper's glands, these are a pair of small glands located below the prostate. They secrete a clear fluid that lubricates the urethra and neutralizes any acidity that may be present due to residual urine.
• Epididymis: This is a pair of coiled tubes that store and carry sperm from the testes to the vas deferens. They are located at the back of each testicle and are paired organs.

Key Points

• Prostate gland -
  • It is one of the male accessory gland that is located below the urinary bladder in front of the rectum.
  • It produces seminal fluid that forms a part of  semen. 
  • This fluid helps in nourishing the sperms.
• Leydig cells - 
  • Leydig cells or interstitial cells are found in between the seminiferous tubules of the testes.
  • These cells synthesize and secrete testicular hormones called androgens.
• Ejaculatory duct - 
  • It is one of the ducts of male reproductive system.
  • It is formed when the vas deferens ascends up into the abdomen and loops over the urinary bladder and is joined by a duct from seminal vesicle.
  • This ejaculatory duct may store and transport sperm into the urethra.
• Penis - 
  • It is the external genitalia in human males.
  • It consists of a special tissue that helps in erection to facilitate insemination.

Corrected Table:

Hence, the correct answer is option 1. 

Concept:

• Spermatogenesis is the process by which sperm are produced in the testis in males.
• In the testis, at puberty sperms are produced from the immature germ cells called spermatogonia.
• Spermatogenesis takes place under the influence of the hypothalamic hormone - Gonadotropin Releasing Hormone (GnRH).
• Sperms (spermatozoa) thus produced are the microscopic haploid male gametes. During the process of fertilization, the union of male and female gametes gives rise to a diploid zygote.
• A sperm is a slender, motile and flagellated structure that is about 60µ in length.
• A sperm comprises a head, a middle piece and a tail.​

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Important Points

• Head -
  • ​The haploid nucleus of sperm is present in the sperm head.
  • The nucleus comprises a vacuole.
  • The anterior portion of the nucleus is covered by a cap-like structure called the acrosome.
  • The acrosome covers the anterior two-thirds of the nucleus.
  • The acrosome is filled with an enzyme that helps in the fertilization of the ovum.
• Midpiece -
  • ​The middle region of the sperm comprises of compact helical mass of mitochondria.
  • The mitochondria provide energy for the movement of the tail.
  • This in turn facilitates sperm motility which is essential for fertilization.
  • Thus the middle piece of the sperm in Human Reproduction helps to produce energy for sperm motility.
• ​Tail - 
  • ​The sperm tail facilitates the movement of the sperm cell by moving in a whip-like manner.
• ​A plasma membrane envelops the whole body of the sperm.
• The plasma membrane helps protect the sperm against extracellular injuries.

Additional Information

• ​The Sertoli cells are present in the seminiferous tubules of the testis.
• They provide nourishment to the developing sperm and are hence also known as nurse cells.

So the correct answer is option 3 (to produce energy for sperm motility).

Concept:

• Fertilization is the process of fusion of the cytoplasm and pronuclei of the male (sperm) and female (ovum) gametes.
• Fertilization takes place in the ampulla region of the fallopian tube.
• During fertilization, once the sperm enters the secondary oocyte, the second meiotic division gets completed in the secondary oocyte.
• The secondary oocyte is now known as the matured ovum.
• The union of male and female gametes gives rise to a diploid zygote.

Important Points

EMBRYONIC DEVELOPMENT:

• The zygote formed during fertilization undergoes rapid mitotic division.
• These divisions are referred to as cleavage divisions.
• The cleavage divisions take place during the passage of the zygote from the fallopian tube to the uterus.
• The daughter cells arising out of cleavage are known as blastomeres.
• Successive cleavage divisions give rise to a ball of blastomeres.
• The blastomeres are enclosed by zona pellucida. This structure is referred to as morula.
• Morula is differentiated into an inner mass of cells that is surrounded by an outer layer of cells.
• The next embryonic stage is called a blastula.
• The blastula is formed by the dynamic rearrangement of blastomeres. This rearrangement of blastomeres gives rise to the formation of a central cavity called the blastocoel.
• Blastocoel is filled with fluid. 
• Once the zona pellucida (outer envelope) disintegrates, it facilitates rapid growth of the blastula.
• The blastocoel expands due to an increase in fluid content. This stage is referred to as a blastocyst.
• The blastocyst comprises an inner cell mass and a thin outer wall called a trophoblast that is separated from each other by the blastocoel.
• The inner cell mass (embryoblast or blastodermic vesicle) forms the body of the embryo. The trophoblast forms the fetal portion of the placenta.
• At this stage, the embryo gets implanted in the endometrium. Implantation takes place with the help of the placenta.
• Blastula later gets converted to the next embryonic stage called gastrula by gastrulation.
• Gastrula is the two-layered stage comprising ectoderm and endoderm.
• At the end of embryonic development, a fetus with three germinal layers - ectoderm, mesoderm and endoderm - is formed.

  ​

• Thus, the correct sequence of embryonic development is as follows:

Fertilization → Second meiotic division → Zygote → Cleavage → Morula → Blastula → Blastocyst (comprises of inner cell mass and trophoblast) → Gastrula

Hence, the correct answer is option 1 (Cleavage → Morula → Blastocyst → Trophoblast and inner cell mass).

The correct answer is Labium minora, labium majora, clitoris

Explanation:

• The external genitalia of the human female are collectively known as the vulva. These structures play key roles in protection, sensory reception, and sexual function.
• The main components of the vulva include the labia minora, labia majora, clitoris, and the vestibular structures.
• The female external genitalia include mons pubis, labia majora, labia minora, hymen and clitoris.
• Mons pubis is a cushion of fatty tissue covered by skin and pubic hair.
• The labia majora are fleshy folds of tissue, which extend down from the mons pubis and surround the vaginal opening.
• The labia minora are paired folds of tissue under the labia majora.
• The opening of the vagina is often covered partially by a membrane called hymen.
• The clitoris is a tiny finger-like structure which lies at the upper junction of the two labia minora above the urethral opening.

Concept:-

• Sperm: it is a male reproductive cell. Each day about 300 million sperm complete spermatogenesis. The human sperm cell is about 70 µm long.
• The nucleus in the head – contains the 23 chromosomes.
• It is the head that blinds to the egg at fertilization.

Ovum: it is a maternal haploid gamete and is primarily concerned with receiving the sperm and is determined to develop into a fully developed multicellular organism after fertilization or without fertilization.

Explanation:

• Hyaluronidase: it is a family of enzymes that degrade hyaluronic acid. It is found in human testes, in bacterial cultures as a by-product, or in the heads of leeches and snake venoms.
• Hyaluronidase enzyme break down the outer membrane of the ovum called zona pellucida.

Additional Information

• Glucocerebrosidase: is a normal component of cell membranes. As senescent cells are degraded, macrophages engulf the cellular debris as a part of routine cell turnover.
• Protease: enzymes involved in the degradation of proteins are called proteases or proteolytic enzymes.
• Amylase: amylases are starch degrading enzymes.

Concept-

After fertilization, the fertilized egg undergoes rapid mitotic divisions are called cleavage.

• Cleavage produces a solid ball of small blastomeres and the embryo now looks like a mulberry is known as a morula.
• The morula, later on, changes into a blastula. The blastula of mammals is called a blastocyst.
• An embryo with about 64 cells is formed within the cell mass. This cavity is called blastocoel and an embryo is called a blastocyst which is composed of an outer envelope of cells, the trophoblast, and inner cell mass.

Explanation-

• As a result of cleavage activities, the zygote moves towards the uterus and forms 2,4,8,16 daughter cells called blastomeres.
• The embryo with 8 to 16 blastomeres is called a morula.

The correct answer is Only A is correct

Concept:

• The uterus is a vital organ in the female reproductive system. It is responsible for housing and nourishing the developing fetus during pregnancy.
• It is supported by various ligaments, and has multiple layers, including the myometrium and endometrium.
• The uterus is connected to the fallopian tubes and the cervix, which leads to the vagina.

Explanation:

• Statement A: The uterus is supported by ligaments attached to the pelvic wall.
  • This is correct. The uterus is supported by several ligaments, including the broad ligament, round ligament, and uterosacral ligament, which help to anchor it to the pelvic wall.
• Statement B: The myometrium is the thin membranous layer of the uterus.
  • This is incorrect. The myometrium is the middle muscular layer of the uterus. The outermost layer is the perimetrium. The
    external thin membranous perimetrium, middle thick layer of smooth muscle, myometrium and inner glandular layer called endometrium that lines the uterine cavity.
• Statement C: The uterus opens into the fallopian tube through the cervix.
  • This is incorrect. The uterus opens into the vagina through the cervix. The fallopian tubes connect to the uterus at the upper part, known as the uterine horns.

The correct option is: (2) Mild uterine contractions stimulating further hormone release

Explanation:

During parturition, the process begins with signals from the fully developed foetus and placenta, which trigger mild uterine contractions called the foetal ejection reflex. These contractions stimulate the release of oxytocin from the maternal pituitary gland.

Oxytocin, in turn, causes stronger uterine contractions, which further stimulate the release of more oxytocin. This creates a positive feedback mechanism, where uterine contractions and oxytocin release reinforce each other until the baby is delivered.

• Option (a): Incorrect. Uterine relaxation does not occur during the process; instead, contractions increase.
• Option (b): Correct. Mild uterine contractions initiate the positive feedback mechanism by stimulating oxytocin release.
• Option (c): Incorrect. Placental hormones do not inhibit uterine contractions during parturition; rather, they support the process.
• Option (d): Incorrect. The placenta is delivered after the infant, not before.

The positive feedback loop between uterine contractions and oxytocin secretion is central to the process of parturition.

The correct answer is 2.0-2.5°C lower than the normal body temperature

Concept:

• The testes are situated outside the abdominal cavity within a pouch called scrotum. The scrotum helps in maintaining the low temperature of the testes (2–2.5°C lower than the normal internal body temperature) necessary for spermatogenesis. In adults, each testis is oval in shape, with a length of about 4 to 5 cm and a width of about 2 to 3 cm. The testis is covered by a dense covering. Each testis has about 250 compartments called testicular lobules

Explanation:

• 2.0-2.5°C lower than the normal body temperature: The primary reason for the extra-abdominal position of the testes is to maintain a temperature that is 2.0-2.5°C lower than the normal body temperature. This cooler environment is necessary for the production of viable sperm. High temperatures can impair spermatogenesis and lead to infertility.

Other Options:

• Narrow pelvis in males: This is not a relevant reason for the position of the testes. The pelvis structure does not determine the positioning of the testes.
• Special protection for testis: While protection is important, it is not the primary reason for the testes being outside the abdominal cavity. The scrotum provides some protection, but the main reason is temperature regulation.
• Prostate gland and seminal vesicles occupy maximum space: This is incorrect as the positioning of the testes is not influenced by the space occupied by other reproductive organs. The prostate gland and seminal vesicles are located inside the pelvic cavity and do not affect the scrotal position of the testes.