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Description: This test will help the students to revise their topics thoroughly .
Number of Questions: 15
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Tags: zygote Onset of Puberty in Females Ovaries, Fallopian Tubes /Oviducts, Uterus, Vagina, Fertilization Mechanical, Chemical and Surgical Method Sex Glands in Human- Male Onset of Puberty in Males:
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The LH surge is mainly accountable for which of the following menstrual cycle events in females?

  1. Apoptosis of nondominant follicles

  2. Endometrial sloughing

  3. A increase in PGF2α

  4. Ovulation

  5. Lactation


Correct Option: D
Explanation:

The LH surge is primarily responsible for ovulation.

Which among the following is the main function of Leydig cells present in testis?

  1. Regulate pituitary secretion of prolactin

  2. Testosterone synthesis

  3. Nitric oxide release

  4. Inhibin secretion

  5. Synthesis of androgen binding protein


Correct Option: B
Explanation:

The primary function of Leydig cells is to synthesize and secrete testosterone. Leydig cells do this in a dose-dependent manner in response to LH.

In mammals, the prevention of polyspermy ensures that the diploid zygote is protected. Which of the following mechanisms is involved in the process of polyspermy?

  1. Resumption of the second meiotic division of the egg

  2. Activation of the polar body to begin mRNA synthesis

  3. Depolarization of the egg membrane by a rise in intracellular calcium

  4. Initiation of the acrosome reaction in the sperm

  5. The zona pellucida is modified by serine proteases that are released from the cortical granules


Correct Option: C
Explanation:

During fertilization, a sperm cell penetrates an oocyte (egg); fusion of sperm and oocyte membranes drives an increase in intracellular calcium in the oocyte. This fusion and rise in calcium causes depolarization of the egg membrane which prevents other sperm cells from fusing with the egg cell (this is the primary block to polyspermy).

Branches of the internal iliac (hypogastric) arteries supply blood to all of the following, except ________________.

  1. vulva

  2. cervix

  3. uterus

  4. ovaries

  5. clitoris


Correct Option: D
Explanation:

The ovaries are supplied by the ovarian arteries which branch directly off of the aorta just below the renal arteries.

Regarding the menstrual cycle in females, which of the following statements is false?

  1. Deviation from the typical 28-day menstrual cycle typically occurs because of different lengths in the follicular phases.  

  2. During menstruation, thromboxane and prostaglandin homeostasis control myometrial and vascular contractions in the uterus.

  3. Prolonged elevations in progesterone levels triggers the LH surge.

  4. Although one oocyte is typically ovulated per cycle, several will begin their development.

  5. The menstrual cycle can be described by the ovarian or uterine cycle.


Correct Option: C
Explanation:

Prolonged elevations in estrogen, not progesterone, triggers the LH surge. Prolonged elevations of progesterone suppress FSH and thus the next menstrual cycle (consider that pregnancy results in elevated progesterone levels, maintaining the endometrium and suppressing ovulation).

A 29 year old European lady underwent bilateral tubal ligation after her last pregnancy. During her procedure, the middle portions of both fallopian tubes were removed. Which function of the fallopian tube is not disrupted by this procedure?

  1. Egg transport

  2. Sperm transport

  3. Embryo transport

  4. Intratubal ciliary motion

  5. Fallopian Tube Sperm Perfusion


Correct Option: D
Explanation:

Removal of the middle portions of both fallopian tubes does not affect the function of the cilia which lines the inside of the fallopian tubes.

A 22 year old lady undergoing laparoscopy is noted to have a cyst on her ovary. The cyst is described as a “blister” on the surface of the ovary. Which of the following is this most consistent with?

  1. Corpus luteum  

  2. Cancer

  3. Impending ovulation

  4. Ectopic pregnancy

  5. Endometriosis


Correct Option: C
Explanation:

During initial follicular growth, the oocyte grows larger, granulosa cells increase in number, and a zona pellucida, or protein matrix, forms around the oocyte. The fluid filling the follicler continues to accumulate and the cellular surface of the follicle thins in preparation for ovulation. This process can be seen grossly and has been described as a blister on the ovarian surface.

MIS or Müllerian inhibiting substance, is a peptide secreted under the direction of SRY (the sex-determining region of the Y chromosome). It is secreted by which cells?

  1. Sertoli cells

  2. Leydig cells

  3. Metanephric kidneys

  4. Mullerian duct epithelium

  5. Germ cells


Correct Option: A
Explanation:

Those testicular cells destined to become Sertoli cells will secrete MIS under the direction of SRY and cause the Müllerian ducst to degenerate.

The human mammary gland is derived from _________________.

  1. protoderm

  2. ectoderm

  3. endoderm

  4. mesoderm

  5. pyoderma


Correct Option: B
Explanation:

Ectoderm is the outermost of the three primary germ layers of an embryo, from which the epidermis, nervous tissue and sense organs develops. The human mammary gland is derived from ectoderm.

Which of the following develops into the placenta?

  1. Umbilical cord

  2. Inner cell mass of the blastocyst

  3. Decidua

  4. Myoblast cells

  5. Trophectoderm


Correct Option: E
Explanation:

The developing embryo has two main populations of cells: an inner cell mass and a trophectoderm. The trophectoderm cells lie at the outer surface of the developing embryo and will become the placenta.

During the follicular phase, which among the following triggers the maturation of early-stage ovarian follicles and dominant follicle?

  1. Matrix-degrading proteases

  2. FSH

  3. hCG

  4. Androgens

  5. Hemopexin degradation


Correct Option: B
Explanation:

Follicle-stimulating hormone (FSH) causes maturation of a cohort of early-stage ovarian follicles; one of these will ultimately become the dominant or graafian follicle.

The mesenchyme arising beneath the germinal epithelium is the origin of which analogous cell types?

  1. Leydig and thecal cells

  2. Spermatogonia and oogonia

  3. Sertoli cells

  4. Sex cords

  5. Granulosa cells


Correct Option: A
Explanation:

Mesenchyme arising beneath the germinal epithelium in the testes is the precursor to testicular interstitial cells, or Leydig cells, while in the ovaries it is the precursor to ovarian stroma or thecal cells.

In mammals, the maternal changes in the kidney during pregnancy includes _____________.

  1. decrease in urine flow through the collecting system

  2. decrease in glomerular filtration rate

  3. decrease in creatinine clearance

  4. decrease in size

  5. decrease in water sodium absorption


Correct Option: A
Explanation:

Urine flows more slowly through the maternal renal collecting system due to dilatation of the ducts. This dilatation is the result of mechanical obstruction by the enlarging uterus along with the relaxing effects of progesterone on smooth muscle.

The hormone human chorionic gonadotropin (hCG) is produced during pregnancy. What is the source of this hormone?

  1. Zona pellucida

  2. Developing trophoblast

  3. Fetal pituitary gland

  4. Maternal pituitary gland

  5. Ovarian corpus luteum


Correct Option: E
Explanation:

A fall in maternal progesterone levels results in sloughing of the endometrial wall and allows the next ovulation cycle to begin. Therefore, in order for an embryo to implant and remain in the uterus, local and systemic maternal progesterone levels must remain elevated. For the first 14 days after ovulation, the corpus luteum secretes progesterone. Without additional support, the corpus luteum spontaneously regresses at the end of a typical menstrual cycle.

The primordial germ cells in a prepubertal male are found in which stage of the cell cycle?

  1. Anaphase

  2. Telophase

  3. Prophase

  4. Interphase

  5. Metaphase


Correct Option: D
Explanation:

Interphase occurs just prior to cell division. Prepubertal male primordial germ cells are reactivated from interphase at puberty and enter rounds of mitoses followed by meiosis 1 and 2 to produce unique haploid sperm.

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